the congenital absence of teeth can seriously affect a young person , both physically and 
 emotionally , especially when the missing tooth is located in the anterior region of the 
 mouth . hypodontia is the congenital absence of teeth and refers to the condition where 
 there is an absence of one or a few teeth . in addition , hypodontia of permanent teeth is fairly common in 
 contemporary populations and is the 
 most common human malformation . both genetic and environmental 
 components are involved in the etiology of hypodontia , and several genetic and syndromic conditions are 
 currently known to increase the risk of hypodontia ; nonetheless , congenitally missing teeth are commonly found in 
 healthy people . the prevalence of hypodontia ranges from 1% in african negroes and australian aborigines 
 to 30% in japanese people , and 
 studies of white subjects have reported higher frequencies of hypodontia among females 
 ( a female - to - male ratio of approximately 3:2 ) . the third molars are the most frequently missing teeth , but they 
 do not need to be replaced ; however , mandibular second premolars ( 2.8% ) , maxillary 
 lateral incisors ( 1.6% ) , and maxillary second premolars and mandibular incisors 
 ( 0.23%-0.08% ) are the most 
 frequently missing teeth that require some type of treatment . hypodontia usually requires extensive and complex treatments , ranging from single 
 restorations to surgery and multiple restorations , associated with lifelong 
 maintenance . several treatment 
 solutions have been presented in the dental literature . in broad 
 terms , the necessary treatment depends on the pattern of tooth absence , the amount of 
 residual spacing , the presence of malocclusion and patient attitudes . one of the key 
 factors for the successful treatment of patients with hypodontia is the 
 interdisciplinary intervention , which involves the close work of a committed team 
 ( general dental practitioner , pediatric dentist , orthodontist , implantologist and 
 prosthodontist ) , where each member contributes with a different expertise to achieve an 
 optimal outcome for the patient . the 
 purpose of this article is to present a case of hypodontia in which the treatment plan 
 consisted of the association of orthodontic , implantology , and prosthetic 
 specialties . a 17-year - old male patient in the final stage of orthodontic treatment presented with 
 the primary second molars in position for space maintenance . hypodontia had been 
 previously diagnosed by the orthodontic team ( figure 
 1 ) , and the patient was referred to the oral rehabilitation clinic ( fob / usp ) 
 for extraction of those teeth and rehabilitation of the area . analyses of the occlusal 
 condition revealed the presence of both canine and protrusive guidance achieved by 
 orthodontic therapy and that the deciduous second molars were in infraocclusion ( figure 2 ) . the patient did not present with any 
 systemic or genetic disorder that could be associated with hypodontia , and the oral 
 hygiene status was satisfactory . preorthodontic panoramic radiograph initial aspect showing infra - occlusion of the primary mandibular right and left 
 second molars several treatment options were considered , including adhesive or conventional fixed 
 bridges and implants , because there were radiographic signs of root resorption in the 
 primary teeth . considering the consecutive cephalometric analyses , which demonstrated 
 that the patient had reached physical maturity , the bone availability , the absence of 
 medical contraindications , and the patient consent , the treatment comprised the 
 extraction of primary teeth and placement of immediate load implants . however , the 
 mesiodistal dimensions of the primary teeth were larger than that required to restore 
 the anatomy of the mandibular second premolar but insufficient to restore the dimensions 
 of a mandibular first molar . thus , the only option was to reduce the mesiodistal 
 distance by orthodontic therapy before implant placement . to plan the prosthetic space 
 and at the same time to guide the orthodontic movement , the occlusal surfaces of the 
 primary teeth were marked according to the mesiodistal dimension of a mandibular second 
 premolar ( figure 3 ) , and the distal surfaces were 
 reduced without changing the infraosseous anatomy to acquire space to fabricate the 
 provisional crowns with anatomic characteristics of mandibular second premolars ( figure 4 ) . this step of prosthetic planning was 
 fundamental to the accomplishment of the orthodontic treatment . occlusal view of the mandibular primary teeth showing the delimitation mark for 
 the proximal reduction occlusal view showing the distal space after cementation of the provisional 
 crown after the planned space closure ( figure 5 ) , the 
 teeth were extracted , and external hex implants with a 4.1 mm rectangular platform were 
 immediately placed ( master porous grip , conexo sistemas de implante , so paulo , sp , 
 brazil ) with immediate load ( figures 6 ) . the 
 ceraone abutment was selected ( conexo sistemas de implante ) and placed at a torque of 
 32 n. the provisional crown was then adapted , cemented with temporary cement ( relyx 
 temp ; 3 m espe , st . paul , mn , usa ) and maintained in infra - occlusion for 4 months . during 
 this period , the orthodontic appliance was maintained for retention of the 
 orthodontically moved mandibular molars . the implants were considered clinically 
 acceptable after clinical ( absence of pain , infection , mobility , or any other signal of 
 pathology into the soft tissues ) and radiographic ( no signs of periimplant radiolucency ) 
 examinations . occlusal view after the planned space closure between the molars and the 
 provisional crowns occlusal view of the provisional crowns after placement of the immediate load 
 implants an impression of the ceraone abutment was taken with the emergence profile customization 
 technique with silicone ( optosil and optosil xantopren ; heraeus 
 kulzer gmbh & co. kg , germany ) . the metal - ceramic crowns were cemented with 
 glass - ionomer cement ( relay x luting 2 ; 3 m espe ) . the final outcome reflected the care taken , especially during the planning of the 
 prosthetic space to be restored ( figure 7 ) . the 
 2-year follow - up revealed maintenance of orthodontic treatment , occlusal plane and oral 
 hygiene , esthetics ( figures 8a and 8b ) , and the stability of the bone level ( figure 9 ) . no mechanical ( ceramic fracture , screw 
 loosening , and loss of retention ) and/or biological complications ( periimplantitis ) were 
 recorded . final occlusal aspect after cementation of metal - ceramic crowns of the mandibular 
 right and left second premolars proximal view after 2 years of follow - up panoramic radiograph after 2 years of follow - up the multidisciplinary approach associated with early diagnosis in individuals with 
 hypodontia of permanent teeth is related to treatment success . however , definitive treatment of the missing teeth is 
 often performed only after eruption of all permanent teeth or completion of orthodontic 
 treatment . the oral patient 's hygiene status and socioeconomic conditions as well as the 
 maintenance therapy should also be considered . multidisciplinary treatment is usually initiated upon the diagnosis of hypodontia , often 
 by the pediatric dentist or general practitioner . the main contribution of these 
 professionals is the prevention of carious lesions and maintenance of the primary teeth 
 in the oral cavity for space maintenance and preservation of alveolar bone for future 
 implant therapy . orthodontic 
 treatment allows for the creation or redistribution of spaces for later 
 rehabilitation . if the primary 
 teeth had not been maintained in the present case , the final prosthetic spaces would not 
 have been large enough for the placement of crowns with the dimensions of mandibular 
 second premolars . the greatest challenge in the treatment of hypodontia is related to 
 treatment planning , which usually depends on the severity of the hypodontia . the treatment options available for 
 these cases are the maintenance of the primary teeth ; orthodontic space closure ; space 
 maintenance ; restoration with adhesive or fixed dentures , tooth transplantation or 
 dental implants ; or orthodontic space redistribution to facilitate the prosthetic 
 treatment . maintenance of the primary teeth should be considered if root resorption has not 
 affected their stability . when 
 extraction of the primary teeth is indicated , orthodontic treatment should be performed 
 to prevent migration of the adjacent and antagonist teeth and to allow for adequate 
 space for prosthetic rehabilitation . in the present case , besides the maintenance of the 
 primary teeth throughout the orthodontic treatment , the prosthetic spaces preserved by 
 provisional crowns were also important because if they had not been completely closed , 
 the class i angle could not have been achieved , possibly causing occlusal and facial 
 alterations , while the 
 maintenance of the original space would require prosthetic crowns with different 
 characteristics than those observed on either first molars or second premolars . the treatment with dental implants may be the best option for patients with hypodontia 
 because this procedure is predictable , stable and provides excellent esthetic 
 results . other treatment 
 options , such as conventional partial fixed dentures , may cause biological damage due to 
 the need to reduce the intact tooth structure ; in young patients , the risk of pulp 
 damage is high due to the large volume of the pulp chamber . when treatment 
 with dental implants is indicated , the possible postpubertal vertical growth of the 
 facial skeleton should be considered , and consecutive cephalometric analyses should be performed to 
 establish the period of growth . these analyses revealed completion of physical growth of 
 our patient ; thus , restoration of the prosthetic space with implants was the treatment 
 of choice . the implant therapy in individuals with hypodontia may be complex due to the limitations 
 caused by the reduced bone thickness , impairing the ideal positioning of 
 implants or requiring the use of implants with a small platform . for this reason , bone 
 grafting is often indicated to compensate for this deficiency . implants with a small 
 platform prevent the achievement of an adequate emergence profile for wide teeth , such 
 as the posterior teeth . in this case , the maintenance of the primary teeth during 
 orthodontic treatment favors the maintenance of the bone architecture , allowing for the 
 placement of implants with a regular platform . the successful management of hypodontia in this case was achieved by a multidisciplinary 
 treatment . maintenance of the primary teeth combined with orthodontic treatment allowed 
 for the placement of endosseous implants to replace the missing teeth , enhancing the 
 esthetics and function .
hypodontia is the congenital absence of one or more teeth and may affect permanent 
 teeth . 
 several options are indicated to treat hypodontia , including the maintenance 
 of primary teeth or space redistribution for restorative treatment with partial 
 adhesive bridges , tooth transplantation , and implants . however , a multidisciplinary 
 approach is the most important requirement for the ideal treatment of hypodontia . 
 this paper describes a multidisciplinary treatment plan for congenitally missing 
 permanent mandibular second premolars involving orthodontics , implantology and 
 prosthodontic specialties .