Patent Publication Number: US-2023135019-A1

Title: Orthodontic Aligner with Bulges

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to PCT patent application PCT/CA2022050135 filed on Jan. 31, 2022, U.S. application Ser. No. 17/808,545 filed on Jun. 24, 2022, and U.S. application Ser. No. 17/812,446 filed on Jul. 14, 2022, and PCT patent application PCT/IB2022/060418 filed on Oct. 28, 2022. 
    
    
     FIELD OF INVENTION 
     This invention relates to orthodontic appliances and, in particular, to an orthodontic aligner or retainer which employs bulges at the aligners to maintain a wedge-shaped space between the occluding surfaces of the upper dental arch and the lower dental arch when the aligners are fully installed to achieve a good orthodontic result. 
     DESCRIPTION OF RELATED ART 
     Interocclusal rest space refers to a space between the occluding surfaces of the upper dental arch and the lower dental arch when the mandible is in the rest position. The Interocclusal rest space usually is 2-4 mm. The Interocclusal rest space is a wedge-shaped space, and it is greater at the anterior teeth than the posterior teeth. When a person having normal occlusion open his mouth, a space between the occluding surfaces of the upper dental arch and the lower dental arch is always wedge-shaped. When an upper and a lower aligner are fully installed in a patient&#39;s mouth for a first time, a space between the occluding surfaces of the upper dental arch and the lower dental arch is formed; this space should be wedge-shaped and should be greater at the anterior teeth than the posterior teeth. If this patient accepts aligner treatment, an aligner usually has a consistent thickness at each portion of the biting wall of the aligner, such that the upper aligner and the lower aligner of this patient would have premature contact over the last molars in an early stage of the orthodontic treatment; and this premature contact may cause molar intrusion. This contact relationship between the upper and lower aligners is not stable, more contact points between the aligners over the premolars and anterior teeth may be permitted while the molar intrusion gradually become severe. When the aligners are permitted to have contacts over the premolars and anterior teeth, the space between the occluding surfaces of the upper and lower dental arches become more stable. After a few weeks of aligner wearing, an open bite problem at the molar region becomes apparent gradually in the patient, and the space between the occluding surfaces of the upper dental arch and the lower dental arch is not a wedge-shaped space; these two occluding surfaces become relatively parallel, and the space has similar width at the anterior teeth and the posterior teeth. The back teeth open bite generated by wearing the aligner gives great trouble to orthodontic treatment and has big influence on patient daily life, such as eating. Some improvement needs to be done to solve this problem. 
     SUMMARY OF THE INVENTION 
     To maintain a wedge-shaped space between the occluding surfaces of the upper dental arch and the lower dental arch when the aligners are fully installed is a precondition to realize a good occlusion of a patient who wears aligners. The present invention provides an orthodontic appliance for repositioning teeth, the teeth form an upper dental arch and a lower dental arch of a patient. The orthodontic appliance comprises an upper aligner conforming to the upper dental arch at the patient&#39;s maxilla and a lower aligner conforming to the lower dental arch at the patient&#39;s mandible; a biting wall of the aligners conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth. Part of the biting wall of one of the aligners is spaced away from a tooth surface of the teeth when the aligners are fully installed, such that at least one bulge is applied at the biting wall; the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the aligners are fully installed and contact each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
     Implementations may include one or more of the following features. A bulge space formed between the bulge and the tooth surface of the teeth may be occupied with a filling material when the aligners are fully installed. A bulge space formed between the bulge and the tooth surface of the teeth may be occupied with another layer of aligner material when the aligners are fully installed. At least one said bulge may be applied over right premolars of the teeth and at least one said bulge may be applied over left premolars of the teeth when the aligners are fully installed. At least one said bulge may be applied over anterior teeth of the teeth when the aligners are fully installed. The bulges may have a shape similar to a natural tooth cusp. Each one of the bulges may cover part of an occlusal surface of one tooth of the teeth. The bulges may cover part of an occlusal surface of both of two adjacent teeth. The bulges may cover part of a side surface of the teeth. The wedged-shape space may be equal to or wider than the Interocclusal rest space. The at least one bulge may comprise two said bulges applied at one of right side and left side of the aligners, and wherein the anterior one of said two bulges is higher than the posterior one of said two bulges. 
     The present invention also provides an orthodontic appliance for repositioning teeth, the teeth forming an upper dental arch and a lower dental arch of a patient. The orthodontic appliance comprises an upper aligner conforming to the upper dental arch and a lower aligner conforming to the lower dental arch. Part of the aligners is spaced away from an incisal edge of anterior teeth of the teeth when the aligners are fully installed, such that one or more bulge of the aligners is applied over the incisal edge of the anterior teeth. 
     Implementations may include one or more of the following features. A bulge space formed between said bulge and the incisal edge may be occupied with a filing material. The filling material may be attached with the aligner. The orthodontic appliance may comprise at least one bite ramp applied at a lingual surface of upper anterior teeth of the teeth, and at least one said bulge is formed over an incisal edge of lower anterior teeth of the teeth; and wherein the at least one bulge and the at least one bite ramp may be dimensioned to have contact with each other when the fully installed aligners make contact. The at least one bite ramp may comprise a guiding surface facing down and forward, and wherein the at least one bulge and the at least one bite ramp are dimensioned to guide the mandible forward by urging a distal end of the at least one bulge to slide forward and upward on the guiding surface when the fully installed aligners make contact. The bulge may be dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of upper posterior teeth of the teeth and lower posterior teeth of the teeth when the fully installed aligners make contact, and wherein the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. The wedge-shaped space may be equal to or greater than an interocclusal rest space. 
     The present invention also provides an orthodontic appliance for repositioning teeth, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprise an upper aligner conforming to the upper dental arch and a lower aligner conforming to the lower dental arch; a biting wall of the aligners conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; part of the biting wall is thicker than other parts of the biting wall, such that at least one bulge is formed in the biting wall; the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the aligners are fully installed and have contact with each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
     Implementations may include one or more of the following features. At least one said bulge may be applied over the anterior teeth when the aligners are fully installed. At least one said bulge may be applied over right first premolars of the teeth and at least one said bulge may be applied over left first premolars of the teeth when the aligners are fully installed. At least one said bulge may be applied over right premolars of the teeth and at least one said bulge may be applied over left premolars of the teeth when the aligners are fully installed. 
     The present invention also provides an orthodontic appliance for holding teeth in place, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprise an upper retainer conforming to the upper dental arch and a lower retainer conforming to the lower dental arch; a biting wall of the retainers conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; part of the biting wall is thicker than other parts of the biting wall, such that at least one bulge is formed in the biting wall; the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the retainers are fully installed and have contact with each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
     Implementations may include one or more of the following features. At least one said bulge may be applied over the anterior teeth when the retainers are fully installed. At least one said bulge may be applied over right first premolars of the teeth and at least one said bulge may be applied over left first premolars of the teeth when the retainers are fully installed. At least one said bulge may be applied over right premolars of the teeth and at least one said bulge may be applied over left premolars of the teeth when the retainers are fully installed. 
     The present invention also provides an orthodontic appliance for repositioning teeth, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprises an upper aligner conforming to the upper dental arch and a lower aligner conforming to the lower dental arch; the aligners define a receiving space for accommodating a crown of the teeth and the receiving space is occupied by the crown of the teeth when the aligners are fully installed; a biting wall of the aligners conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; part of the biting wall is spaced outwardly away from the receiving space, such that at least one bulge is formed at the biting wall; and the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the aligners are fully installed and contact each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
     Implementations may include one or more of the following features. A bulge space formed between the bulge and the tooth surface of the teeth may be occupied with a filling material when the aligners are fully installed. A bulge space formed between the bulge and the tooth surface of the teeth may be occupied with another layer of aligner material when the aligners are fully installed. At least one said bulge may be applied over right first premolars of the teeth and at least one said bulge may be applied over left first premolars of the teeth. At least one said bulge may be applied over right premolars of the teeth and at least one said bulge may be applied over left premolars of the teeth. At least one said bulge may be applied over anterior teeth of the teeth. The bulges may have a shape similar to a natural tooth cusp. Each one of the bulges may cover part of an occlusal surface of one tooth of the teeth. The bulges may cover only a cusp of one tooth of the teeth. The bulges may cover part of an occlusal surface of both of two adjacent teeth. The bulges may cover part of a side surface of the teeth. The wedged-shape space may be equal to or wider than the Interocclusal rest space. The at least one bulge may comprise two said bulges applied at one of right side and left side of the aligners, and wherein the anterior one of said two bulges is higher than the posterior one of said two bulges. 
     The present invention also provides an orthodontic appliance for repositioning teeth, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprises an upper aligner conforming to the upper dental arch and a lower aligner conforming to the lower dental arch; the aligners define a receiving space for accommodating a crown of the teeth and the receiving space is occupied by the crown of the teeth when the aligners are fully installed; at least part of the aligners conforming to an incisal edge of anterior teeth of the teeth is spaced outwardly away from the receiving space, such that at least one bulge is formed at the aligners. 
     The present invention also provides an orthodontic appliance for holding teeth in place, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprises an upper retainer conforming to the upper dental arch and a lower retainer conforming to the lower dental arch; the retainers define a receiving space for accommodating a crown of the teeth and the receiving space is occupied by the crown of the teeth when the retainers are fully installed; a biting wall of the retainers conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; part of the biting wall is spaced outwardly away from the receiving space, such that at least one bulge is formed at the biting wall; and the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the retainers are fully installed and contact each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
     Implementations may include one or more of the following features. A bulge space formed between the bulge and the tooth surface of the teeth may be occupied with a filling material when the retainers are fully installed. A bulge space formed between the bulge and the tooth surface of the teeth may be occupied with another layer of retainer material when the retainers are fully installed. At least one said bulge may be applied over right first premolars of the teeth and at least one said bulge may be applied over left first premolars of the teeth when the retainers are fully installed. At least one said bulge may be applied over right premolars of the teeth and at least one said bulge may be applied over left premolars of the teeth when the retainers are fully installed. At least one said bulge may be applied over anterior teeth of the teeth. The bulges may have a shape similar to a natural tooth cusp. Each one of the bulges may cover part of an occlusal surface of one tooth of the teeth. The bulges may cover only a cusp of one tooth of the teeth. The bulges may cover part of an occlusal surface of both of two adjacent teeth. The bulges may cover part of a buccal surface of the teeth. 
     The present invention also provides an orthodontic appliance for repositioning teeth, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprise an upper aligner conforming to the upper dental arch and a lower aligner conforming to the lower dental arch; and the aligners define a receiving space for accommodating a crown of the teeth and the receiving space is occupied by the crown of the teeth when the aligners are fully installed. Part of the aligners is spaced outwardly away from the receiving space, such that at least one bulge is formed at the aligners, and the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the aligners are fully installed and contact each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
     Implementations may include one or more of the following features. The at least one bulge may be applied over a buccal surface of the teeth when the aligners are fully installed. The at least one bulge may be applied over a lingual surface of the teeth when the aligners are fully installed. The at least one bulge may be applied over an occlusal surface of posterior teeth of the teeth when the aligners are fully installed. The at least one bulge may be applied over an incisal edge of anterior teeth of the teeth when the aligners are fully installed. The at least one bulge may be applied over a buccal surface of anterior teeth of the teeth when the aligners are fully installed. The at least one bulge may be applied over a buccal surface of canines of the teeth when the aligners are fully installed. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of embodiments of the invention in conjunction with the accompanying figures and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various objects, features and advantages of the invention will be apparent from the following description of embodiments of the invention, as illustrated in the accompanying drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments of the invention. 
         FIG.  1    is a vertical sectional view of part of a dentition, showing a wedge-shaped space between the occluding surfaces of the upper and lower dental arches; 
         FIG.  2    is a vertical sectional view of part of a dentition according to a first embodiment, showing a bulge applied over a lower first premolar; 
         FIG.  3    is a vertical sectional view of part of a dentition, showing a variation of the first embodiment and a bulge applied over an upper first premolar; 
         FIG.  4    is a vertical sectional view of part of a dentition, showing a first cross-section A-A and a second cross-section B-B of a bulge applied over an upper canine; 
         FIG.  5    is a vertical sectional view of part of a dentition, showing a height of a bulge; 
         FIG.  6    is a vertical sectional view of part of a dentition, showing a variation of the first embodiment; 
         FIG.  7    is a vertical sectional view of part of a dentition according to a second embodiment, showing two bulges applied over right side of the aligners; 
         FIG.  8    is a vertical sectional view of part of a dentition, showing a variation of the second embodiment. 
         FIG.  9    is a vertical sectional view of part of a dentition, showing a variation of the second embodiment. 
         FIG.  10    is a vertical sectional view of part of a dentition according to a third embodiment, showing six bulges applied at right side of the aligners. 
         FIG.  11    is a vertical sectional view of part of a dentition according to a fourth embodiment, showing eleven bulges applied at right side of the aligners. 
         FIG.  12    is a vertical sectional view of part of a dentition according to a fifth embodiment, showing one bulge applied around the incisal edge of four incisors. 
         FIG.  13    is a vertical sectional view of part of a dentition according to a sixth embodiment, showing two bulges applied around the incisal edge of four incisors. 
         FIG.  14    is a vertical sectional view of part of a dentition according to a seventh embodiment, showing four bulges applied around the incisal edge of four incisors. 
         FIG.  15    is a side sectional view along line C-C of the part of the dentition shown in  FIG.  14   . 
         FIG.  16    is a vertical sectional view of part of a dentition, showing a variation of the seventh embodiment. 
         FIG.  17    is a side sectional view along line D-D of the part of the dentition shown in  FIG.  16   . 
         FIG.  18    is a vertical sectional view of the incisors of a dentition according to an eighth embodiment, showing a bite ramp applied at a lingual surface of an upper incisor and a bulge applied around a lower incisal edge. 
         FIG.  19    is a vertical sectional view of the incisors of a dentition, showing a variation of the eighth embodiment. 
         FIG.  20    is a vertical sectional view of the incisors of a dentition according to a ninth embodiment, showing a bulge applied around an upper incisal edge and a bulge applied around a lower incisal edge. 
         FIG.  21    is a vertical sectional view of the incisors of a dentition, showing a variation of the ninth embodiment. 
         FIG.  22    is a vertical sectional view of the incisors of a dentition according to a variation of the eighth embodiment, showing the bite ramp comprising a guiding surface. 
         FIG.  23    is a vertical sectional view of the incisors of a dentition, showing a variation of the ninth embodiment. 
         FIG.  24   . is a vertical sectional view of the incisors of a dentition according to a tenth embodiment, showing a bulge applied around a lower incisal edge at the lower retainer. 
         FIG.  25   . is a vertical sectional view of the canines of a dentition according to a eleventh embodiment, showing a bulge of the aligner applied over the buccal surface of the lower canine. 
         FIG.  26    is a vertical sectional view of the canines of a dentition according to a variation of the eleventh embodiment, showing a bulge of the aligner applied over the buccal surface of the lower canine. 
         FIG.  27    is a vertical sectional view of the premolars of a dentition according to a twelfth embodiment, showing a bulge of the aligner applied over the occlusal surface of the upper premolar. 
     
    
    
     The dotted lines represent teeth and the solid line represent aligner. Part of the dotted lines next to the solid line represents a crown of the teeth, this part of the dotted lines also represents a receiving space of the aligner. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     To maintain a wedge-shaped space between occluding surfaces of the upper dental arch and the lower dental arch when aligners are fully installed is a precondition for a patient to have a good occlusion. The present invention provides an orthodontic appliance for repositioning teeth, the teeth form an upper dental arch and a lower dental arch of a patient, the orthodontic appliance comprises an upper aligner conforming to the upper dental arch located at this patient&#39;s maxilla and a lower aligner conforming to the lower dental arch located at this patient&#39;s mandible; an aligner biting wall of the aligners conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; and part of the aligner biting wall is spaced away from a surface of the teeth when the aligners are fully installed, such that at least one bulge is applied at the biting wall of the aligners, and a bulge space is formed between the bulge and the tooth surface; the bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the aligners are fully installed and contact each other, and this wedge-shaped space is greater at premolars than molars. The shape of the space between upper and lower occlusal surfaces is determined by the thickness of the aligners and by the shape and the position of the bulges, the thickness of the aligners usually is 0.5-0.7 mm; by employing the bulges with different height at different sites or by employing the bulge only at certain location, this wedge-shaped space can be maintained by the bulges. A dental arch includes posterior teeth and anterior teeth. 
     We can use another way to define the bulge of the aligner. The aligners define a receiving space which is designed for accommodate a crown of the teeth and is occupied by the crown of the teeth when the aligners are fully installed; a biting wall of the aligners conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; part of the biting wall is spaced outwardly away from the receiving space, such that at least one bulge is formed at the biting wall. We can define a bulge of a retainer in the same way. 
     When a patient with normal occlusion makes a small opening movement of his mandible, the mandible makes circular motions with the head of condyloid process of the mandible as the center. When the patient opens his mouth a little, a width of the wedge-shaped space between the upper and lower occluding surfaces at a site (for example right lower first molar) is proportional to a distance from this site (right lower first molar) to the head of condyloid process. For a patient with upper and lower aligners fully installed, if the aligners have contact at second molars and the thickness of the aligners is 0.7 mm, the width of the wedge-shaped space at the second molars is at least 1.4 mm; the distance from the lower incisors to the head of condyloid process is approximate double the distance from the lower second molar to the head of condyloid process, such that the width of the wedge-shaped space should be at least 2.8 mm at the lower incisors. To maintain the width of the wedge-shaped space at the lower incisors, at least one bulge which has a height of 2.1 mm needs to be applied to occupy the wedge-shaped space and to maintain the stability of the wedge-shaped space. Usually, a height of an aligner bulge may vary from 1.2 mm to 3 mm according to the treatment requirement. A width of the wedge-shaped space at one of the lower teeth refers to the distance from the middle point of an occluding surface of that tooth to the occluding surface of the upper dentition. A distance from that tooth to the head of the condyloid process refers to the distance from the middle point of the occluding surface of that tooth to the head of condyloid process. If an aligner case having good occlusion while taking off the aligners, the configuration of the wedge-shaped space with the aligners being fully installed and contacting each other is determined by the thickness of the aligners, the formation of the dental arches, the shape of the mandible and TMJ; the bulge is dimensioned and positioned to maintain the specific configuration of the wedge-shaped space between occluding surfaces of the upper dental arch and the lower dental arch when the aligners are fully installed and contact each other. 
     In a 3-dimensional virtual representation of a treatment plan, a wedge-shaped space with specific configuration should be arranged between the occluding surfaces of upper dental arch and lower dental arch, such that the aligner bulges at the biting wall of the aligners can be arranged easily to maintain the wedge-shaped space when the aligners are fully installed and contact each other. This virtual representation of the treatment plan may be 2D or 3D. A width of the posterior part of the wedge-shaped space between the occlusal surfaces of the upper second molar and the lower second molar should be about twice of the thickness of the aligner, and a width of the anterior part of the wedge-shaped space between the occluding surfaces of the upper incisor and the lower incisor should be about twice of the width of the posterior part. The dimension and position of the bulge may vary according to different treatment requirement. 
       FIG.  1    is a vertical cross section view of part of a dentition, showing part of the right side of the dentition. This figure shows that a wedge-shaped space  120  exists between occlusal surfaces  108  of the upper posterior teeth and the lower posterior teeth when an upper aligner  16  and a lower aligner  16  are in fully installed position  34 . The biting wall  124  of the lower aligner  16  only has contact  36  with the biting wall  124  of the upper aligner  16  over the second molars. At least one repositionable tooth which is arranged to be repositioned is among the teeth of the dental arches. An aligner  16  usually has a consistent thickness at each portion of the biting wall  124  of the aligner  16 , such that a part of the biting wall  124  of the upper aligner  16  over the last upper molar  206  and a part of the biting wall  124  of the lower aligner  16  over the last lower molar  201  usually have premature contact  36  in an early stage of the orthodontic treatment, and this figure shows the premature contact  36 . After a few weeks of aligner wearing, this premature contact  36  may cause the upper and lower last molars to intrude and an open bite problem at molars region to appear gradually in the patient; the space  120  between the occluding surfaces of the upper and lower dental arches would not be a wedge-shaped space, and the two occluding surfaces of the upper dental arch and the lower dental arch become relatively parallel, with the space  120  having similar width at the anterior teeth and the posterior teeth. The occlusal plane  103  refers to an imaginary surface that theoretically touches the incisal edges of the anterior teeth and the tips of the occlusal surfaces of the posterior teeth. A receiving space  101  defined by the aligners is occupied by the crowns of the teeth when the aligners are in fully installed position  34 . 
     In the embodiments of this application tooth  210  is upper canine, tooth  209  is upper first premolar, tooth  208  is upper second premolar, tooth  207  is upper first molar, and tooth  206  is upper second molar; tooth  205  is lower canine, tooth  204  is lower first premolar, tooth  203  is lower second premolar, tooth  202  is lower first molar, and tooth  201  is lower second molar. Canines and incisors are anterior teeth, premolars and molars are posterior teeth.  FIGS.  1  to  11    show part of the right side of the dentition, and in these cases the left side of the dentition may have the same arrangements and design at the aligners. 
       FIG.  2    is a vertical cross section view of part of a dentition, showing part of the right side of the dentition. This figure shows that a wedge-shaped space  120  exists between occlusal surfaces  108  of upper posterior teeth and lower posterior teeth when an upper aligner  16  and a lower aligner  16  are in fully installed position  34 . Part of a biting wall  124  of the lower aligner  16  spaces up from the occlusal surface  108  of lower first premolar  204 , such that a bulge  105  is formed at the biting wall  124  of the lower aligner  16  and located over the lower first premolar  204 . A receiving space  101  defined by the aligners  16  is completely occupied by the crowns of the teeth. Part of a biting wall  124  of the lower aligner  16  spaces away from the receiving space  101 , such that a bulge  105  is formed at the biting wall  124  located over tooth  204 . A bulge space  100  is formed between the bulge  105  and the occlusal surface  108  of the tooth  204 ; the bulge space  100  communicates with the receiving space  101  and is beyond the receiving space  101 . A bulge  105  may be applied over an occlusal surface of upper premolars to get a similar result. The bulge has a shape similar to a natural tooth cusp in this embodiment, but the bulge may have other shapes. In this case, at least one bulge  105  of the aligners is applied over right premolars and at least one bulge  105  of the aligners is applied over left premolars; bulges applied over incisors are not shown in this figure. In this case at least one bulge may be applied over an incisal edge of the incisors. The bulge  105  has a contact point  36  with the upper aligner  16 . The aligners  16  also have contact  36  over the last molars. The aligners  16  and the bulges  105  are dimensioned to maintain a wedged-shaped space  120  between the occlusal surfaces  108  of the upper posterior teeth and the lower posterior teeth, and this space  120  is occupied by the aligners  16 , which has contact with each other. The space  120  is greater at premolars than molars. The bulge  105  may be applied over a functional cusp of the teeth or over a non-functional cusp of the teeth. The bulge  105  may also be applied over a fossa of an occlusal surface of one or more tooth. A bulge may only cover part of an occlusal surface of a tooth; a bulge may cover a whole occlusal surface of a tooth. The bulge may cover a tooth cusp of one or more tooth. The bulge may cover part of a tooth cusp of a tooth. The bulge may have any shape. The bulge may cover the occlusal surfaces of more than one tooth. The bulge may cover an incisal edge of one or more tooth. 
       FIG.  3    is a vertical cross section view of part of a dentition, showing part of the right side of the dentition. Upper and lower aligners are fully installed. A bulge  105  is applied over an occlusal surface  108  of upper first premolar  209 . Here a space between the bulge  105  and the occlusal surface  108  is filled with a filling material  110 . The filling material  110  is attached with the aligner  16 . The upper bulge  105  has a contact point  36  with the lower aligner  16 . The aligners  16  also have contact over the last molars. 
       FIG.  4    is a vertical cross section view of part of a dentition and a magnified view of a bulge  105 , showing two cross-sections of the bulge  105 . Upper and lower aligners  16  are fully installed. The bulge  105  is applied over an incisal edge of upper right canine  210 . In some cases, a bulge may be applied over lower canines. The cross-section A-A is made at the base  121  of the bulge  105 . The cross-section B-B is made at the distal end  123  of the bulge  105 . The cross-section A-A has greater area than the cross-section B-B. The bulge  105  has a shape similar to a natural tooth cusp, the bulge  105  may have a size similar to a natural tooth cusp or may have a greater size than a natural tooth cusp. An area of a cross section of the bulge  105  become smaller gradually from a base  121  of the bulge  105  to a distal end  123  of the bulge  105 . The distal end  123  of the bulge  105  has contact with the lower aligner  16  when the fully installed aligners make contact. A cusp-shaped bulge  105  has better contact with the biting wall  124  of the opposite aligner  16 . The bulge  105  in this application may be applied with other shapes, and a cusp-shaped bulge is one of the preferred embodiments. The bulge may have any shape according to the treatment requirement, for example a shape like an incisal edge. 
       FIG.  5    is a vertical cross section view of part of a dentition and a magnified view of a bulge  105  over tooth  210 , showing a height h of the bulge  105 . Upper and lower aligners  16  are fully installed. The height of the bulge  105  is the distance from a distal end  123  of the bulge  105  to the occlusal plane  103 . 
       FIG.  6    is a vertical cross section view of part of a dentition, showing part of the right side of the dentition. Upper and lower aligners  16  are fully installed. In this embodiment, the bulge  105  is formed extending over tooth  210  and tooth  209 . A bulge space  100  is formed between the bulge  105  and the tooth surface of tooth  210  and tooth  209 . The bulge  105  has a shape similar to a natural tooth cusp. The bulge  105  covers part of the occlusal surface  108  of tooth  209  and the tooth cusp of tooth  210 . The bulge  105  has a contact point  36  with the lower aligner  16 . 
       FIGS.  7 ,  8  and  9    are vertical cross section views of part of a dentition, showing part of the right side of the dentition. An upper aligner  16  and a lower aligner  16  are in fully installed position  34 .  FIG.  7    shows that two bulges  105  are applied at the right side of the upper aligner  16 , one bulge  105  is applied over upper canine  210  and one bulge  105  is applied over upper first premolar  209 . In this case, two bulges  105  are applied at both right side and left side of the upper aligner  16 . In some cases, two bulges  105  may be applied at both right side and left side of the lower aligner  16 , one at anterior teeth and one at premolars.  FIG.  8    shows that one bulge  105  is applied over upper canine  210  and one bulge  105  is applied lower first premolar  204 , but these two bulges have no occlusal contact with each other.  FIG.  9    shows one bulge  105  applied over the upper canine  210  and one bulge  105  applied over the lower canine  205 , and these two bulges have occlusal contact  36  with each other. In  FIG.  7   , the bulge  105  over the canine  210  is higher than the bulge  105  over the first premolar  209 , and the distal end of these two bulges  105  contact the lower aligner  16 . In  FIG.  8   , the bulge  105  over the canine  210  is higher than the bulge  105  over the first premolar  204 , the distal end of each one of the bulges  105  has contact with the opposite aligner  16 . In all these figures, a wedge-shaped space  120  is maintained between the occlusal surfaces  108  of the upper posterior teeth and the lower posterior teeth when the upper aligner  16  has contact with the lower aligner  16 . The bulge  105  over the canine may cover the incisal edge and the buccal surface of the canine. 
       FIG.  10    is a vertical cross section view of part of a dentition, showing part of the right side of the dentition. An upper aligner  16  and a lower aligner  16  are in fully installed position  34 . One bulge  105  is applied over the tooth  210 , and one bulge  105  is applied over the tooth  209 , one bulge  105  is applied over the tooth  208 , and one bulge is applied over the tooth  205 , one bulge  105  is applied over the tooth  204 , and one bulge  105  is applied over the tooth  203 . These bulges  105  are applied over functional cusps of the teeth. The bulge  105  over the canine  205  is higher than the bulges  105  over the premolar  204  and premolar  203 . The bulges  105  over functional cusps are gradually become higher from posterior teeth to anterior teeth. Spaces  100  are formed between the bulges  105  and the tooth surfaces. The bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the fully installed aligners make contact, and this wedge-shaped space is greater at premolars than molars. 
       FIG.  11    is a vertical cross section view of part of a dentition, showing part of the right side of the dentition. An upper aligner  16  and a lower aligner  16  are in fully installed position  34 . One bulge  105  is applied over the tooth  210 , one bulge  105  is applied over the tooth  209 , one bulge  105  is applied over the tooth  208 , and two bulges  105  are applied over the tooth  207 , and one bulge is applied over the tooth  205 , and one bulge  105  is applied over the tooth  204 , and one bulge  105  is applied over the tooth  203 , and two bulges are applied over the tooth  202 , and one bulge  105  is applied over the mesial cusp of the tooth  201 . These bulges  105  are applied over functional cusps of the teeth. The bulges  105  over the premolar  208  and premolar  209  are higher than the bulges  105  over the molar  207 . The bulges  105  over the premolar  204  and the premolar  203  are higher than the bulges  105  over the molar  202  and molar  201 . 
     The bulges  105  are dimensioned and positioned to maintain a wedge-shaped space  120  between an occlusal surface of the upper posterior teeth and an occlusal surface of the lower posterior teeth when the lower aligner  16  has contact with the upper aligner  16 , and this wedge-shaped space  120  is greater at premolars than molars. The bulge  105  is dimensioned to have contact with the opposite aligner when the fully installed aligners make contact. No limitation on quantity of bulges, we can apply as many bulges on an aligner as a treatment need. 
     In dentistry, centric relation is a relationship of the mandible to the maxilla irrespective of vertical dimension or tooth position. Centric relation is the mandible jaw position in which the head of the condyle is situated as far anterior and superior as it possibly can within the mandibular fossa. Eccentric relation is the relation of the mandible to the maxilla other than centric relation. All the embodiments in this application may be applied when the mandible is in centric relation; all the embodiments may also be applied when the mandible is in eccentric relation. 
     To maintain the wedge-shaped space  120 , bulges  105  at the biting wall of the aligners should be applied. A distal end  123  of each one of the bulges  105  at one of the aligners is dimensioned to have contact with the other aligner when the fully installed aligners make contact; In some cases at least one bulge over first premolars and canines of the teeth is applied at the right side of the aligners and at least one bulge over first premolars and canines is applied at the left side of the aligners; in some case at least two bulges are applied at the left side of the aligners and at least two bulges are applied at the right side of the aligners, and the anterior bulge is higher than the posterior bulge. 
     A bulge  105  of an aligner  16  applied over lower canines should be taller than a bulge  105  of that aligner applied over lower premolars, and a bulge  105  of that aligner  16  applied over premolars should be taller than a bulge  105  of that aligner applied over molars; in some cases, a bulge  105  over an incisal edge of lower incisors may be applied and this bulge  105  may be the tallest bulge in this aligner. If the wedge-shaped space  120  between the occlusal surfaces of the upper posterior teeth and the lower posterior teeth is maintained by the upper and lower aligners  16  which have the bulges  105  with different heights at different location, premature contact between the aligners over the last molar can be prevented, such that undesirable molar intrusion and open bite at molar region could be prevented. While taking off the aligners the upper dental arch and lower dental arch may also have good occlusal contact at most of the back teeth, and one of the orthodontic treatment aims is to reach maximal intercuspation in harmony with centric relation. Another advantage of this arrangement is that the occlusal force is much more evenly distributed to different parts of the aligners and keep the whole aligners in a fully installed position. A functional cusp refers to a tooth cusp that occlude with the opposing teeth in centric occlusion. In normal occlusion, the lingual cusps of the upper posterior teeth and the buccal cusps of the lower posterior teeth are functional cusps. A non-functional cusp refers to a tooth cusp that do not occlude with the opposing teeth in centric occlusion. In normal occlusion, the lingual cusps of the lower posterior teeth and the buccal cusps of the upper posterior teeth are non-functional cusps. In a deep overbite case, a bulge  105  may be applied over anterior teeth. In an anterior open bite case, bulges  105  may be applied at posterior teeth only. 
     When the space  120  occupied by the aligners  16  is equal to or a little greater than the Interocclusal rest space when the aligners  16  is fully installed, a relatively continuous contact between the two aligners may be maintained; in this situation if only the anterior parts of the aligners have contact with each other the anterior teeth may receive continuous intrusive force and deep overbite may be relieved; if only the posterior parts of the aligners have contact with each other the back teeth may receive continuous intrusive force and anterior teeth open bite may be relieved. 
     All the bulges  105  are dimensioned to have contact  36  with the opposite aligner  16  when the aligners have contact with each other. 
       FIG.  12    is a vertical sectional view of part of a lower dentition  118  according to a fifth embodiment, showing one bulge  105  is applied around the incisal edges  130  of four lower incisors  128  when an aligner  16  is in fully installed position  34 . A bulge space  100  is formed between the bulge  105  and the incisal edge  130 . 
       FIG.  13    is a vertical sectional view of part of a lower dentition  118  according to a sixth embodiment, showing two bulges  105  are applied around the incisal edges  130  of four lower incisors  128  when an aligner  16  is in fully installed position  34 , each bulge  105  covers the incisal edges of two lower incisors. A bulge space  100  is formed between the bulge  105  and the incisal edge  130 . 
       FIG.  14    is a vertical sectional view of part of a lower dentition  118  according to a seventh embodiment, showing four bulges  105  are applied around the incisal edges  130  of four lower incisors  128  when an aligner  16  is in fully installed position  34 , each bulge  105  covers the incisal edge of one lower incisor. A bulge space  100  is formed between the bulge  105  and the incisal edge  130 . The bulge  105  has a shape like an incisal edge  130 . 
       FIG.  15    is a side sectional view C-C of the part of the lower dentition  118  shown in the  FIG.  14   , showing a bulge space  100  is between the bulge  105  and the incisal edge  130 . A height of the bulge  105  refers to the distance from the distal end  123  of the bulge  105  to the occlusal plane of the lower dental arch  118 , in this figure the height of the bulge  105  is the same as the distance from the distal end  123  to the incisal edge  130  of the tooth  128 . The bulge  105  formed over the incisal edge  130  also covers part of a buccal surface  106  of the tooth  128 . A receiving space  101  defined by the aligner  16  is completely occupied by the crown of tooth  128  when the aligner  16  is in fully installed position  34 , and the bulge space  100  is left between the bulge  105  and the tooth  128  when the aligner  16  is in fully installed position  34 . The bulge space  100  is also between the bulge  105  and the receiving space  101 . 
       FIG.  16    is a vertical sectional view of part of a lower dentition  118 , showing a variation of the seventh embodiment. Four bulges  105  are applied around the incisal edges  130  of four lower incisors  128  when an aligner  16  is in fully installed position  34 , each bulge  105  covers an incisal edge  130  of one lower incisor  128 . A space formed between the bulge  105  and the incisal edge  130  is filled with a filling material  110 , this filling material  110  may be composite or impression material, or any material which is permitted to be filled into the bulge space  100 , this material  110  may be attached with the aligner  16 . This filling material  110  may also be another layer of aligner material. 
       FIG.  17    is a side sectional view D-D of the part of the lower dentition  118  shown in the  FIG.  16   , showing the bulge space between the bulge  105  and the incisal edge  130  is occupied by a filling material  110  when the aligner  16  is in fully installed position  34 . The space between the bulge  105  and the receiving space  101  is filled with a filling material  110 . 
     In some cases, a bulge may cover part of an incisal edge of one anterior tooth; in some cases, a bulge may cover any part of an incisor edge of the anterior teeth of one dental arch; in some cases, a bulge may cover an incisal edge of all the upper or lower anterior teeth. 
     In some cases, one or more bulge is applied over an incisal edge of lower anterior teeth of the teeth; in some cases, one or more bulge is applied over an incisal edge of upper anterior teeth of the teeth; In some cases, the bulges are applied over an incisal edge of upper anterior teeth and lower anterior teeth. The bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the fully installed aligners make contact, and this wedge-shaped space is greater at premolars than molars. 
     A bulge  105  over an incisal edge may have a shape like an incisal edge or a tooth cusp. The bulge  105  may have any shape according to the orthodontic treatment requirement. 
       FIG.  18    is a vertical sectional view of part of a dentition according to an eighth embodiment, showing that a bite ramp  104  of an upper aligner is applied at a lingual surface of the upper incisor  126  in the upper dental arch  116  and a bulge  105  of a lower aligner is applied around an incisal edge  130  of the lower incisor  128  in the lower dental arch  118  when the upper and lower aligners  16  are in fully installed position  34 . The receiving space  101  is fully occupied by the crown of the tooth  128 . The lower bulge  105  has good contact  36  with the upper aligner bite ramp  104 . In this situation, this contact  36  between the upper and lower aligners  16  generates force, this force is an intrusion force working on the upper and lower anterior teeth, and this arrangement can help to correct the deep overbite at anterior teeth. This arrangement is also helpful to maintain the normal occlusal relationship of upper and lower dentitions and inhibit aligners displacement. The bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the fully installed aligners make contact, and this wedge-shaped space is greater at premolars than molars. When a bulger of a lower aligner is applied together with a bite ramp of an upper aligner in a deep bite patient, the height of the bulge may be shorter than a bulge applied over premolars. 
       FIG.  19    is a vertical sectional view of part of a dentition, showing a variation of the eighth embodiment, showing that an aligner bite ramp  104  over a space is applied at a lingual surface of the upper incisor  126  in the upper dental arch  116 ; a part of the lower aligner  16  over an incisal edge  130  of the lower incisor  128  has greater thickness  112  than other part of the biting wall of the lower aligner  16 , such that a bulge  105  is applied over the incisal edge  130  of the lower incisor  128  in the lower dental arch  118  when the upper and lower aligners are in fully installed position  34 . The lower bulge  105  has good contact  36  with the upper aligner bite ramp  104 . In some cases, the aligner bite ramp  104  may also be formed by employing aligner material with greater thickness  112  than other part of the upper aligner  16 . In all the embodiments in this application, the bulge of an aligner may be formed by the aligner material which is thicker than other part of the aligner, and the bite ramp of an aligner may also be formed with the aligner material which is thicker than other part of the aligner. The aligner bulge  105  with greater thickness  112  may be applied in the other part of the biting wall  124  of the aligner; usually the aligner bulge  105  may be applied over the premolars and the anterior teeth when the aligners are fully installed, especially the first premolars. The bulge  105  with great thickness  112  may also be applied at the biting wall  124  of the retainers  18 ; usually the retainer bulge  105  may be applied over the premolars and the anterior teeth when the retainers  18  are fully installed, especially the first premolars. 
     All the bulge at the bite wall of the aligners in the embodiments of this application may be formed with greater thickness of aligner material. Part of the biting wall of the aligners is thicker than other parts of the biting wall, such that at least one bulge is formed at the biting wall; the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the aligners are fully installed and have contact with each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. 
       FIG.  20    is a vertical sectional view of part of a dentition according to a ninth embodiment, showing a bulge  105  applied over an incisal edge  130  of the upper incisor  126  in the upper dental arch  116  and a bulge  105  applied over an incisal edge  130  of the lower incisor  128  in the lower dental arch  118  when the upper and lower aligners  16  are in fully installed position  34  and make contact  36 . The distal end  123  of the lower bulge  105  has contact  36  with the lingual surface of the upper aligner  16 . The bulge  105  is dimensioned to maintain a wedge-shaped space  120  between an occlusal surface of the upper posterior teeth and an occlusal surface of the lower posterior teeth when the lower aligner  16  has contact with the upper aligner  16 , and this wedge-shaped space  120  is greater at premolars than molars. 
       FIG.  21    is a vertical sectional view of part of a dentition, showing a bulge  105  applied over an incisal edge  130  of the lower incisor  128  in the lower dental arch  118  when the upper and lower aligners  16  are in fully installed position  34 . The distal end  123  of the lower bulge  105  has contact  36  with the lingual surface of the upper aligner  16 . 
       FIG.  22    is a vertical sectional view of part of a dentition, showing an aligner bite ramp  104  of the upper aligner applied at a lingual surface  107  of the upper incisor  126  and a bulge  105  of the lower aligner applied over an incisal edge  130  of the lower incisor  128  when the upper and lower aligners  16  are in fully installed position  34  and make contact  36 . The bite ramp  104  comprises a guiding surface  109  facing down and forward, and a distal end of the bulge  105  is permitted to slide forward and upward on the guiding surface  109  of the aligner bite ramp  104 . The distal end  123  of the bulge  105  has contact  36  with the guiding surface  109  of the aligner bite ramp  104 . The bulge  105  and the bite ramp  104  are dimensioned to guide the mandible forward by urging the distal end of the bulge  105  to slide forward and upward on the guiding surface  109  when the patient close his mouth. This arrangement is very helpful to correct AP position in class II cases of young children. 
       FIG.  23    is a vertical sectional view of part of a dentition, showing a bulge  105  of upper aligner applied over an incisal edge  130  of the upper incisor  126  in the upper dental arch  116  when the upper and lower aligners  16  are in fully installed position  34 . The bulge  105  also covers part of a buccal surface  106  of the tooth  126 . A bulge space  100  is formed between the bulge  105  and the incisal edge  130 . The lower aligner  16  has contact  36  with a lingual surface of the upper bulge  105 . A wedge-shaped space is maintained between the occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the fully installed aligners  16  make contact. This embodiment may be applied in class III malocclusion patient. In some cases, a bulge  105  may also be added over the incisal edge  130  of lower incisors  128 . 
     An aligner bulge may be extended to cover part of at least one of a buccal surface and a lingual surface of the teeth. 
       FIG.  24    is a vertical sectional view of part of a dentition, showing a bulge  105  of a lower retainer  18  applied over a lower incisal edge  130  of a lower incisor  128  when the upper and lower retainer  18  are in fully installed position  34 . The receiving space  101  is fully occupied by the crowns of the teeth. A bulge space  100  is formed between the bulge  105  and the incisal edge  130 . The distal end  123  of the bulge  105  of the lower retainer  18  has contact  36  with a lingual surface of the upper retainer  18 . The bulge  105  is dimensioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the fully installed retainers  18  make contact and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. The retainer bulge may be applied over the anterior teeth when the retainers are fully installed. The retainer bulges may be applied over right first premolars of the teeth and left first premolars of the teeth when the retainers are fully installed. The retainer bulges may be applied over right premolars of the teeth and left premolars of the teeth when the retainers are fully installed. 
       FIG.  24    shows an orthodontic appliance for holding teeth in place. The teeth form an upper dental arch and a lower dental arch of a patient. The orthodontic appliance comprises an upper retainer  18  conforming to the upper dental arch and a lower retainer  18  conforming to the lower dental arch. The retainers  18  define a receiving space  101  for accommodating a crown of the teeth and the receiving space is occupied by the crown of the teeth when the retainers are fully installed; a biting wall of the retainers conforms to an occlusal surface of posterior teeth of the teeth and an incisal edge of anterior teeth of the teeth; part of the biting wall is spaced outwardly away from the receiving space, such that at least one bulge  105  is formed at the biting wall; and the at least one bulge is dimensioned and positioned to maintain a wedge-shaped space between occlusal surfaces of the upper posterior teeth of the teeth and the lower posterior teeth of the teeth when the retainers are fully installed and have contact with each other, and the wedge-shaped space is greater at premolars of the teeth than molars of the teeth. The retainer is very similar to the aligner; all the embodiments of the aligners in this application can be applied in the retainer also. 
       FIG.  25    is a vertical sectional view of part of a dentition, showing a bulge  105  of the lower aligner  16  applied over a buccal surface  106  of the lower canine  205  in the lower dental arch  118  when the upper and lower aligners  16  are in fully installed position  34 . The bulge  105  has contact  36  with an upper aligner bite ramp  104  over the lingual surface  107  of the upper canine  210  of the upper dental arch  116 . The bulge  105  is dimensioned and positioned to maintain a wedge-shaped space  120  between the occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the aligners  16  are fully installed and have contact, and this wedge-shaped space  120  is greater at premolars than molars. The bulge of aligner over the canine may be applied on other anterior teeth when the aligner are fully installed. 
       FIG.  26    is a vertical sectional view of part of a dentition, showing a bulge  105  of lower aligner  16  applied over a buccal surface  106  of the lower canine  205  in the lower dental arch  118  when the upper and lower aligners  16  are in fully installed position  34 . The bulge  105  has contact  36  with the upper aligner  16 . The bulge  105  is dimensioned and positioned to maintain a wedge-shaped space  120  between the occlusal surfaces of the upper posterior teeth and the lower posterior teeth when the aligners  16  are fully installed and have contact, and this wedge-shaped space  120  is greater at premolars than molars. 
       FIG.  27    is a vertical sectional view of part of a dentition, showing a bulge  105  of upper aligner  16  applied over an occlusal surface  108  of the upper first premolar  209  in the upper dental arch  116  when the upper and lower aligners  16  are in fully installed position  34  and have contact with each other. The bulge  105  has contact  36  with the lower aligner  16 . The bulge  105  is dimensioned and positioned to maintain a wedge-shaped space  120  between the occlusal surfaces  108  of the upper posterior teeth and the lower posterior teeth when the aligners  16  are fully installed and have contact with each other and this wedge-shaped space  120  is greater at premolars than molars. The bulge may be applied over the lower first premolar also. In this embodiment at least one aligner bulge is applied over the right first premolars and at least one aligner bulge is applied over the left first premolars when the aligners are fully installed. Similar arrangements may also be applied at retainers mentioned in this application, in this case at least one retainer bulge is applied over the right first premolars and at least one retainer bulge is applied over the left first premolars when the retainers are fully installed 
       FIGS.  1  to  11    show the bulges applied over canines, premolars and molars;  FIGS.  12  to  23    show the bulges applied over anterior teeth.  FIGS.  25  and  26    show the bulges applied over buccal surface of the anterior teeth.  FIG.  27    shows the bulge applied over first premolar. The bulges over incisors and the bulges over canines, premolars and molars may be applied together in one embodiment. Different embodiments in this application may be applied together in one case to maintain a wedge-shaped space  120  between the occluding surfaces of the maxillary and mandibular teeth when the aligners are fully installed and have contact with each other, and in most cases the aligners should be permitted to have bilateral, steady contact with each other. In some cases, the upper aligner and lower aligner with bulges only have contact at some specific areas in a period of a treatment and gradually develop to better contact with each other; for a deep overbite case, only anterior parts of the aligners have contact in a period of the treatment and gradually develop to better contact between the aligners when the deep overbite is relieved; for an anterior open bite case, only posterior parts of the aligners have contact in a period of the treatment and gradually develop to better contact between the aligners when the open bite is relieved. 
     The bulge  105  mentioned in this application can be manufactured by using general known methods and technique. The method may comprise the following steps: 
     (a) providing a positive model of a dentition; 
     (b) providing an added structure on an occlusal surface or an incisal edge of the positive model; 
     (c) forming the aligner over the positive model and over the added structure such that the aligner includes a bulge which is applied at the added structure&#39;s location. 
     The added structure is a non-dental structure, i.e. it does not form part of the patient&#39;s initial or final tooth arrangement in the dentition model. Instead, the added structure is designed to provide a sacrificial protrusion for the subsequent bulge. 
     Dentition modelling may use common knowledge in the field of orthodontics to obtain a digital model of a dentition of a patient using a digital scanner, such as iTero. After the repositioning treatment has been design, a plurality of modified digital dentition models can be defined having a plurality of tooth arrangements. One of the modified digital dentition models and a digital model of an added structure can be merged into a combined digital model. A positive model of the combined digital model can be printed out by a 3D printing machine using existing techniques and materials. Similarly, method to program the aligner tooth arrangements by computer are well known. Retainer can be made in the same way with the aligner. 
     REFERENCE LIST 
     
         
         Teeth  12   
         Tooth surface  13   
         Aligner  16   
         Retainer  18   
         Fully installed position  34   
         Contact point  36   
         Bulge space  100   
         Receiving space  101   
         Tooth cusp  102   
         Occlusal plane  103   
         Bite ramp  104   
         Bulge  105   
         Buccal surface  106   
         Lingual surface  107   
         Occlusal surface  108   
         Guiding surface.  109   
         Filling material  110   
         Aligner with greater thickness  112   
         Upper dental arch  116   
         Lower dental arch  118   
         Wedge-shaped space  120   
         Bulge base  121   
         Aligner cusp  122   
         Bulge distal end  123   
         Biting wall  124   
         Upper incisor  126   
         Lower incisor  128   
         Incisal edge  130   
         Aligner incisal edge  132   
         Lower Second molar  201   
         Lower First molar  202   
         Lower Second premolar  203   
         Lower First premolar  204   
         Lower Canine  205   
         Upper Second molar  206   
         Upper First molar  207   
         Upper Second premolar  208   
         Upper First premolar  209   
         Upper Canine  210   
       
    
     Terms such as “top”, “bottom”, “distal”, “proximate”, “below,” “above,” “upper, are used herein for simplicity in describing relative positioning of elements of the aligners, as depicted in the drawings or with reference to a patient&#39;s dentition when the aligners are installed. Although the present invention has been described and illustrated with respect to preferred embodiments and preferred uses thereof, it is not to be so limited since modifications and changes can be made as understood by those skilled in the art.