surgery of the chin has been used for decades to achieve a balance of the lower third of the face . horizontal osteotomy for chin augmentation is an old and established procedure while medpore has become popular in the recent years for facial skeletal augmentation . the present study has been undertaken to compare the advantages and disadvantages of medpore and osseous augmentation in genioplasty procedure . the study comprised 16 patients with retruded chin , attending the outpatient department ( opd ) of oral and maxillofacial surgery , faculty of dental sciences , c.s.m . medical university , lucknow , india . out of the 16 patients , 8 underwent medpore augmentation ( group b ) while the other 8 underwent osseous augmentation ( group a ) . it contains those relations that are suitable for cases requiring advancement genioplasty and have been divided into soft tissue and skeletal relations [ gonzales ullao , rickettes , steiner epker and fish , dipaolo , quadrilateral analysis and burstone , ( cogs analysis)][figure 1 ] . cephalometric hard and soft tissue points and associated reference planes lateral cephalometric radiographs were taken preoperatively and 1 week , 6 weeks and 3 months postoperatively in a standardized fashion with teeth in centric relation and the lips in repose ( i.e. no obvious strain ) . each cephalogram was traced on acetate paper and the following landmarks were located on each tracing . the horizontal reference axis was defined by registering on sella ( s ) orienting 7 inferior to s - nasion ( s - n ) plane . pogonion line was taken to evaluate the deficiency of chin coupled with e - line of ricketts , 0-meridian of ulloa and facial contour angle was considered to obtain the millimeter deficiency present in chin preoperatively and changes postoperatively . normally , the anterior projection of the mentum approaches approximately the vertical line from the subnasale in the male and slightly anterior to the vertical line from the nasion in the female . the soft tissue relationships of the chin to the lip and nose are very useful for evaluation of chin projection . when the esthetic plane is formed from the nose tip to the pogonion , the upper and lower lips both lie 12 mm posterior to the esthetic plane . the ideal relationship between the chin and the lips are the same as those for caucasians . the chin should rest slightly posterior to the lower lip , and the lower lip should rest posterior to the upper lip.[16 ] on frontal examination , the lower face is often subdivided into an upper one - third [ extending between the subnasale and lip contact ( stomion ) ] , and a lower two third ( measured between the stomion and mentum ) . in the indians , the upper third is slightly shorter and the lower two - third is slightly longer . other things that need to be considered include the depth of the labiomental fold , the thickness of the chin pad , and the labiomental angle . dissection was performed through a standard intraoral vestibular approach , where the paravestibular incision extending from first premolar on one side to the first premolar on the other , was given . the mental nerves were exposed bilaterally by dissecting posteriorly along the inferior border of mandible in the bicuspid region and mucoperiosteum was elevated . three vertical marks were inscribed to avoid transverse deviation and rotation of the inferior segment . osteotomy lines were present 45 mm below the apices of the cuspids and 34 mm below the level of the mental foramina , so as not to jeopardize these structures.[710 ] care was taken to achieve sharp and straight cuts without creating curves . after mobilization of the lower segment , the chin was moved to the predicted position . the overlying soft tissue envelop was also inspected from the outside every now and then such that there is free mobility of the soft tissues surrounding the implant . a chin dressing with mild compression was placed after the operation to reduce swelling , to assist in mentalis closure , and to prevent hematoma or seroma formation . the patients were kept on a complete liquid diet for a week and progressed to a soft and then regular diet afterward . it contains those relations that are suitable for cases requiring advancement genioplasty and have been divided into soft tissue and skeletal relations [ gonzales ullao , rickettes , steiner epker and fish , dipaolo , quadrilateral analysis and burstone , ( cogs analysis)][figure 1 ] . cephalometric hard and soft tissue points and associated reference planes lateral cephalometric radiographs were taken preoperatively and 1 week , 6 weeks and 3 months postoperatively in a standardized fashion with teeth in centric relation and the lips in repose ( i.e. no obvious strain ) . each cephalogram was traced on acetate paper and the following landmarks were located on each tracing . the horizontal reference axis was defined by registering on sella ( s ) orienting 7 inferior to s - nasion ( s - n ) plane . pogonion line was taken to evaluate the deficiency of chin coupled with e - line of ricketts , 0-meridian of ulloa and facial contour angle was considered to obtain the millimeter deficiency present in chin preoperatively and changes postoperatively . normally , the anterior projection of the mentum approaches approximately the vertical line from the subnasale in the male and slightly anterior to the vertical line from the nasion in the female . the soft tissue relationships of the chin to the lip and nose are very useful for evaluation of chin projection . when the esthetic plane is formed from the nose tip to the pogonion , the upper and lower lips both lie 12 mm posterior to the esthetic plane . the ideal relationship between the chin and the lips are the same as those for caucasians . the chin should rest slightly posterior to the lower lip , and the lower lip should rest posterior to the upper lip.[16 ] on frontal examination , the lower face is often subdivided into an upper one - third [ extending between the subnasale and lip contact ( stomion ) ] , and a lower two third ( measured between the stomion and mentum ) . in the indians , the upper third is slightly shorter and the lower two - third is slightly longer . other things that need to be considered include the depth of the labiomental fold , the thickness of the chin pad , and the labiomental angle . dissection was performed through a standard intraoral vestibular approach , where the paravestibular incision extending from first premolar on one side to the first premolar on the other , was given . the mental nerves were exposed bilaterally by dissecting posteriorly along the inferior border of mandible in the bicuspid region and mucoperiosteum was elevated . three vertical marks were inscribed to avoid transverse deviation and rotation of the inferior segment . osteotomy lines were present 45 mm below the apices of the cuspids and 34 mm below the level of the mental foramina , so as not to jeopardize these structures.[710 ] care was taken to achieve sharp and straight cuts without creating curves . after mobilization of the lower segment , the chin was moved to the predicted position . the overlying soft tissue envelop was also inspected from the outside every now and then such that there is free mobility of the soft tissues surrounding the implant . a chin dressing with mild compression was placed after the operation to reduce swelling , to assist in mentalis closure , and to prevent hematoma or seroma formation . the patients were kept on a complete liquid diet for a week and progressed to a soft and then regular diet afterward . sliding genioplasties were performed for seven female and one male adult patients presenting with a complaint of small or weak chins . the mean amount of horizontal chin movement was 10.75 mm . during the same period , eight chin augmentations with medpore the esthetic results , as determined by both the patient and surgeon , were satisfactory during the follow - up period of 3rd week to 6 months [ figures 29 ] . in medpore group , there was no resorption of hard tissue and soft tissue decreased by a mean value of 2.82 mm over a period of 6 months , while in osseous genioplasty group , there occurred a mean hard tissue resorption of 1.33 mm and soft tissue decreased by a mean value of 3.30 mm over a period of 6 months [ table 1 and 2 ] . preoperative full face photograph of a patient of medpore chin augmentation group ( group b ) preoperative profile photograph of a patient of medpore chin augmentation group ( group b ) postoperative full face photograph of a patient of medpore chin augmentation group ( group b ) postoperative profile photograph of a patient of medpore chin augmentation group ( group b ) preoperative full face photograph of a patient of osseous augmentation group ( group a ) preoperative profile photograph of a patient of osseous augmentation group ( group a ) postoperative full face photograph of a patient of osseous augmentation group ( group a ) postoperative profile photograph of a patient of osseous augmentation group ( group a ) analysis of changes in hard and soft tissues ( group a ) ( n = 8) analysis of changes in hard and soft tissues ( group b ) ( n = 8) 0 in the medpore group , no infection or alloplastic reaction was found . the osseous genioplasty group experienced no infections , nonunion , or malunion . a mild and transient lower lip numbness developed in only one patient . the osseous genioplasty group experienced no infections , nonunion , or malunion . a mild and transient lower lip numbness developed in only one patient . it is a biologically inert polymer with regularly spaced pores measuring 100300 m in diameter . this pore size allows significant tissue ingrowth instead of surrounding fibrous tissue capsule formation , which results in rapid , strong implant fixation . it has been used as an onlay graft for augmentation of the cranium , mandibular angle , orbital rim , malar region , and mental region . the material is easily carved and somewhat flexible . long - term follow - up evaluation demonstrated no problems related to bioincompatibility and a minimal complication rate ( 3% infection and 8% displeasing contours ) . advancement genioplasty with horizontal osteotomy of lower border of mandible is a versatile , commonly carried out orthognathic procedure . horizontal osteotomy of lower border of mandiblular symphysis through the intraoral approach was first introduced by richard trauner and hugo obwegeser . horizontal osteotmy of chin can correct a horizontal or vertical deficiency or excess of chin . the procedure is suitable for any chin , short or long , and for laterogenia . in the medpore group , i.e. group b , no infection or alloplastic reaction physically , medpore is a pure , biocompatible , strong substance that does not resorb or degenerate . it is stable in the long term with a good tensile strength , resistance to stress and fatigue , and a virtual lack of surrounding soft tissue reaction . encapsulation and predisposition to movement are responsible for the majority of late complications reported for smooth surface implants ( nonporous implant ) . screw application of the implant to the underlying skeleton allows precise predictable contouring , thus limiting the need for revisional surgical procedure . when the hard tissue and soft tissue changes were compared , it was found that the hard tissue to soft tissue ratio was 1:0.87 , 6 months postoperatively in group a , while in group b the hard tissue to soft tissue ratio was 1:0.78 . this shows that horizontal osteotomy of lower border of mandible , i.e. , osseous genioplasty gives better soft tissue predictability than alloplastic augmentation.[1619 ] another aspect of this study has been to evaluate the ease of technique while using medpore biomaterial implants . out of the 16 cases the average time of the surgery beginning from the placement of incision to closure of the site were noted . the average time of operation in the cases treated by medpore was 45 minutes to 1 hour , and for those treated by osseous genioplasty , it was 1.52 hours . medpore produces the same satisfactory result as osseous genioplasty in cases of mild to moderate horizontal chin deficiency . all the patients from both the groups showed significant improvement in facial profile , high degree of satisfaction and the resulting improved self - esteem from both procedures.because of good fixation , medpore is quite different from traditional alloplastic implant . it did not depress into underlying bone , so the result was maintained , i.e. , showed no resorption of underlying bone.surrounding tissue has shown biocompatibility to medpore biomaterial implant , which remains nonimmunogenic , nonallergic and nontoxic , with no evidence of resorption or alteration.more invasive nature of osteotomy in case of osseous genioplasty leads to the potential for more complications , more significant swelling and longer postoperative recovery.medpore implant can be given when only straight advancement is indicated and no vertical or asymmetric movement is indicated.in this advancement procedure , the soft tissue follows the skeletal framework of the chin . hard tissue to soft tissue relation in case of osseous genioplasty was 1:0.88 , while in the case of medpore augmentation it was 1:0.77 , i.e. , soft tissue predictability of osseous genioplasty was better in comparison with medpore augmentation . medpore produces the same satisfactory result as osseous genioplasty in cases of mild to moderate horizontal chin deficiency . all the patients from both the groups showed significant improvement in facial profile , high degree of satisfaction and the resulting improved self - esteem from both procedures . because of good fixation it did not depress into underlying bone , so the result was maintained , i.e. , showed no resorption of underlying bone . surrounding tissue has shown biocompatibility to medpore biomaterial implant , which remains nonimmunogenic , nonallergic and nontoxic , with no evidence of resorption or alteration . more invasive nature of osteotomy in case of osseous genioplasty leads to the potential for more complications , more significant swelling and longer postoperative recovery . medpore implant can be given when only straight advancement is indicated and no vertical or asymmetric movement is indicated . in this advancement procedure , the soft tissue follows the skeletal framework of the chin . hard tissue to soft tissue relation in case of osseous genioplasty was 1:0.88 , while in the case of medpore augmentation it was 1:0.77 , i.e. , soft tissue predictability of osseous genioplasty was better in comparison with medpore augmentation . in brief , medpore is indicated for mild to moderate horizontal chin deficiency and to modify chin shape , i.e. , for minor contour irregularity , while osseous genioplasty is recommended for any chin , i.e. , short , long or for laterogenia .
background : genioplasty deals with small area of craniofacial complex , namely , chin . 
 alloplastic chin implants and sliding genioplasty represent the two currently accepted methods of chin augmentation . 
 chin augmentation with medpore has become popular in the recent years.material and methods : the study comprised 16 patients having retruded chin , out of whom 8 patients underwent sliding genioplasty while the other 8 underwent chin augmentation using medpore . 
 the versatility and benefits of the two techniques are discussed.result and conclusion : all the patients achieved satisfactory results with no complication . 
 both the techniques can be used for mild to moderate retrogenia , while in the case of severe retrogenia , sliding genioplasty is recommended . 
 medpore is especially used for revision of chin shape . 
 medpore can give the same satisfactory result as osseous genioplasty in cases of mild to moderate horizontal chin deficiency . 
 all the patients from both the groups showed significant improvement in facial profile and high degree of satisfaction resulting in improved self - esteem .