a recent survey showed that oral cancer , which accounts for 2.8% of all malignant tumors in europe , is the most common cause of maxillofacial defects .
moreover , the incidence of oral cancer in china is relatively high compared with the rest of the world .
severe deficiencies in appearance , pronunciation and swallowing occur when maxillofacial defects cause oral  nasal transport .
, prosthodontists have tried to help these patients by separating the oral and the nasal cavity using obturator prostheses to improve deglutition , articulation , pronunciation and facial appearance , and in some cases to support the orbital contents to prevent enophthalmos and diplopia .
the absence of teeth , and the size and configuration of the maxillary defect , may influence the masticatory function of patients wearing an obturator prosthesis and may lead to a poor rehabilitation outcome .
moreover , the adequate retention of these prostheses is difficult to achieve , especially for large - sized defects . for many years
, prosthodontists have tried different ways to achieve better retention for cases who have undergone extensive maxillectomy .
schmidt et al . used zygomatic and standard endosseous implants to retain prostheses in near - total and total maxillectomy patients .
reported the case of a partial maxillectomy patient with an obturator that was supported by five mini - dental implants .
the author concluded that mini - dental implants can be used when there is a lack of adequate bone tissue for conventional implant placement in the region of the resection .
however , for some patients , these implants are not acceptable due to their general health , personal inclination or economic reasons . finding
payne and welton designed a latex rubber balloon attached to a denture that was inflated with air to fill the surgical defect , but its clinical usage has not been reported . in the last decade ,
this article is the first to describe the restoration of maxillary defects with inflatable obturator prostheses based on silicone , which also represented an alternative technique for maxillofacial rehabilitation .
a 20-year - old male patient diagnosed with fibrous dysplasia was referred to the department of prosthodontics , peking university school and hospital of stomatology .
his chief complaints were deficiencies in speaking and swallowing after extensive resection of the maxilla 3 months previously ( figure 1 ) .
the patient had undergone bilateral sub - total maxillectomy , which resected most of the maxillary structures ; only a portion of the maxillary tuberosity remained . no surgical reconstruction or any graft for the defect had been applied .
clinical investigation showed an extensive defect of the palatal area and crest ridge , which was classified as a class iv defect according to aramany 's classification .
transport between the oral cavity and the nasal cavity was observed , and the surgical site showed tolerable healing with the formation of a scab and no sign of recrudescence ( figure 2 ) . as the maxillectomy defect included almost the whole palatal area , the amount of undercut area available to provide retention for a prosthesis was very limited , making adequate retention by traditional methods extremely difficult .
however , the use of endosseous implants in pathological bone has not been thoroughly investigated and some commentaries suggest avoiding it for cases of fibrous dysplasia . furthermore , the patient did not want to accept implant therapy for economic reasons .
sectional maxillary prosthesis , including a complete denture and an inflatable obturator , was used to restore the extensive maxillary defect .
the definitive maxillary denture ( luciton 199 denture base material ; dentsply , york , pennsylvania , usa ) was made according to the mandibular dentition with proper occlusion contact .
on the intaglio side of the denture , an appropriate undercut that imitated an edentulous ridge contour was made so that the complete denture could be retained afterwards ( figure 3 ) .
then , impression material ( rapid putty soft ; coltene / whaledent , altsttten , switzerland ) was placed into the intaglio surface of the denture .
this material is easy to control and it is not likely to enter deep undercut areas under appropriate pressure .
when the impression was made , we ensured that the maxillary denture had a good occlusal contact with the mandibular dentition .
the jaw position was guided to the appropriate occlusal vertical dimensions by measuring the distance of the points marked on the patient 's face at rest , and was maintained in this position until the impression material had set ( figures 3 and 4 ) .
the impression was poured with dental stone ( die - stone type iii ; heraeus , south bend , indiana , usa ) to form the working cast , and a one - way air valve ( botou shengwei factory , botou city , hebei province , china ) was fixed on the palatal surface of the obturator when the obturator prosthesis was made .
odontosil ( dreves , unna , germany ) silicone material was used to process the hollow silicone obturator prosthesis in the laboratory ( figure 5 ) .
the obturator prosthesis and the definitive denture were then trialed by the patient , and an adequate vertical dimension and retention of the prosthesis was demonstrated ( figure 6 ) .
when the patient tried the sectional maxillary prosthesis by himself , the compressed obturator was firstly seated in the defect , and the patient could inflate it using a portable air pump ( figure 7 ) to connect the installed air - valve on the palatal surface of the obturator .
when inflated , the obturator was well - fitted with extending evenly into the undercuts .
the denture was then seated on the inflated obturator by engaging the suitable undercuts on the palatal surface of the obturator formed during the manufacture of the denture . when the patient wishes to remove the obturator ,
the compressed air pump is connected directly with the valve to deflate it after the denture is removed .
a 68-year - old male complained of deficiencies in speaking , swallowing and mastication after bilateral total maxillectomy 3 months previously ( figure 8) .
a hollow inflatable silicone obturator prosthesis combined with a complete denture was prescribed for the patient according to the procedure described above ( figures 9 and 10 ) . when inflated , the obturator was well - fitted and provided adequate support and retention for the complete denture .
a 20-year - old male patient diagnosed with fibrous dysplasia was referred to the department of prosthodontics , peking university school and hospital of stomatology .
his chief complaints were deficiencies in speaking and swallowing after extensive resection of the maxilla 3 months previously ( figure 1 ) .
the patient had undergone bilateral sub - total maxillectomy , which resected most of the maxillary structures ; only a portion of the maxillary tuberosity remained . no surgical reconstruction or any graft for the defect had been applied .
clinical investigation showed an extensive defect of the palatal area and crest ridge , which was classified as a class iv defect according to aramany 's classification .
transport between the oral cavity and the nasal cavity was observed , and the surgical site showed tolerable healing with the formation of a scab and no sign of recrudescence ( figure 2 ) . as the maxillectomy defect included almost the whole palatal area , the amount of undercut area available to provide retention for a prosthesis was very limited , making adequate retention by traditional methods extremely difficult .
however , the use of endosseous implants in pathological bone has not been thoroughly investigated and some commentaries suggest avoiding it for cases of fibrous dysplasia . furthermore , the patient did not want to accept implant therapy for economic reasons .
sectional maxillary prosthesis , including a complete denture and an inflatable obturator , was used to restore the extensive maxillary defect .
the definitive maxillary denture ( luciton 199 denture base material ; dentsply , york , pennsylvania , usa ) was made according to the mandibular dentition with proper occlusion contact .
on the intaglio side of the denture , an appropriate undercut that imitated an edentulous ridge contour was made so that the complete denture could be retained afterwards ( figure 3 ) .
then , impression material ( rapid putty soft ; coltene / whaledent , altsttten , switzerland ) was placed into the intaglio surface of the denture .
this material is easy to control and it is not likely to enter deep undercut areas under appropriate pressure .
when the impression was made , we ensured that the maxillary denture had a good occlusal contact with the mandibular dentition .
the jaw position was guided to the appropriate occlusal vertical dimensions by measuring the distance of the points marked on the patient 's face at rest , and was maintained in this position until the impression material had set ( figures 3 and 4 ) .
the impression was poured with dental stone ( die - stone type iii ; heraeus , south bend , indiana , usa ) to form the working cast , and a one - way air valve ( botou shengwei factory , botou city , hebei province , china ) was fixed on the palatal surface of the obturator when the obturator prosthesis was made .
odontosil ( dreves , unna , germany ) silicone material was used to process the hollow silicone obturator prosthesis in the laboratory ( figure 5 ) .
the obturator prosthesis and the definitive denture were then trialed by the patient , and an adequate vertical dimension and retention of the prosthesis was demonstrated ( figure 6 ) .
when the patient tried the sectional maxillary prosthesis by himself , the compressed obturator was firstly seated in the defect , and the patient could inflate it using a portable air pump ( figure 7 ) to connect the installed air - valve on the palatal surface of the obturator .
when inflated , the obturator was well - fitted with extending evenly into the undercuts .
the denture was then seated on the inflated obturator by engaging the suitable undercuts on the palatal surface of the obturator formed during the manufacture of the denture . when the patient wishes to remove the obturator ,
the compressed air pump is connected directly with the valve to deflate it after the denture is removed .
a 68-year - old male complained of deficiencies in speaking , swallowing and mastication after bilateral total maxillectomy 3 months previously ( figure 8) .
a hollow inflatable silicone obturator prosthesis combined with a complete denture was prescribed for the patient according to the procedure described above ( figures 9 and 10 ) . when inflated , the obturator was well - fitted and provided adequate support and retention for the complete denture .
in case 1 , a large palatal defect was evident after surgery for fibrous dysplasia .
oral  nasal transport and the resultant functional deficiencies greatly affected the patient 's quality of life .
however , the lack of structures to provide retention made it extremely difficult to construct a conventional prosthesis for him .
a recent report of the use of endosseous implants has been described in a patient with fibrous dysplasia ; however , osseointegration in the pathological bone at a microscopic level has not yet been proven .
the inflatable hollow obturator prosthesis may be a suitable alternative in patients such as this one who did not want to undergo oral implant treatment for medical and/or economic reasons .
when dealing with extensive defects , the prosthesis requires greater extension into the defect and is therefore heavier . as described in the literature , the continuous stress placed on the remaining tissues by a large , heavy obturator jeopardizes their health , compromises the function of the prosthesis and can cause discomfort to the patient .
the use of a hollow maxillary obturator may reduce the weight of the prosthesis by up to 33% , depending on the size of the maxillary defect .
shaker used medical - grade silicone to fabricate the obturator part of the prosthesis with mushroom - like extensions .
it was retained by this resilient material which engaged the soft tissue undercuts within the defect . however , the extension into the undercut by this obturator has to be limited , or else its insertion may cause discomfort and bleeding .
our inflatable obturator can be easily placed in undercuts when compressed and extends further when inflated , thereby improving retention without causing obvious discomfort .
compared with the semi - customized balloon - shaped inflatable latex obturator designed by payne and welton , this new hollow and inflatable obturator is completely customized according to the configuration and size of defects and has been proven clinically . with this advantage , an obturator with the same shape as the defect can extend into the undercut area and engage the undercut more evenly .
the inflatable hollow obturator is lightweight , can be retained well and creates an adequate oral 
deglutition , pronunciation and mastication can be improved and the psychological impact of extensive maxillectomies on patients can therefore be minimized . when faced with patients with microstomia after surgery , an inflatable obturator may also be an alternative option as the obturator can be seated into the oral cavity while deflated and compressed . in cases of extensive maxillectomy in which implants can not be used , as in the two cases in this report
, the inflatable obturator makes prosthetic treatment more acceptable as good retention is achieved by engaging more undercut areas after inflation . in cases of partial maxillectomy , the use of an inflatable obturator may minimize deleterious forces on the remaining structures as further support is gained from surrounding tissues .
silicone - based inflatable obturators offer a simple technique for the reconstruction of maxillary defects , can be used by most prosthodontists and offer a treatment alternative for patients who may not be able to receive conventional implants .
however , the extent to which the inflatable obturator improves pronunciation , deglutition and mastication compared with traditional prostheses , and the long - term serviceability of this prosthesis , requires further investigation .
 the presence of a large palatal or maxillary defect after partial or total maxillectomy for tumor , trauma or congenital deformation poses a challenge to prosthodontists , particularly when the use of an implant can not be considered . 
 this case report described the use of an air valve in a hollow silicone obturator to manufacture an inflatable obturator that could be extended further into undercut area to retain itself . 
 the inflatable obturator exhibited adequate retention , stability and border sealing , thereby improving the masticatory , pronunciation and swallowing functions of patients . 
 it may be a suitable alternative treatment option to an implant - retained obturator . 