Prosthetically driven alveolar reconstructions: a retrospective study

Abstract This study aims to evaluate the post-extraction alveolar bone reconstruction amongst 12 patients exhibiting loss of buccal bone plate in a tooth of the anterior region of the maxilla using the prosthetically-driven alveolar reconstruction technique (PDAR). In PDAR, a partial fixed provisional prosthesis (PFPP [conventional or adhesive]) with a specially designed pontic maintains the clot in a mechanically stable position during alveolar regeneration. Moreover, the pontic design, in hourglass shape and located in the subgingival area, also prevents gingival margins from collapsing. Gingival recession was evaluated through the 6-month healing period. Cone beam computed tomography (CBCT) was performed 1 month before and 8 months after PDAR treatment. For the primary outcome, in the panoramic imaging, the central area of bone defect in each tooth was selected for linear measurements. Measurements of the vertical buccal bone gain and the gain in thickness in the alveolar bone crest were obtained 8 months after PDAR. Descriptive statistics and intraclass correlation coefficient analysis were conducted. After treatment, all patients showed bone formation (a mean vertical gain of 7.1±3.7 mm, associated with a horizontal mean gain of 4.5±1.4 mm in the alveolar bone crest). The intraclass correlation coefficient for the measurements performed using CBCT was 0.999. No gingival recession, greater than 1 mm, was observed. Lower-morbidity procedures without the use of biomaterials may be a useful in post-extraction alveolar ridge regeneration and/or preservation. PDAR promoted alveolar bone formation without flaps, grafts and membranes.

Resumo Este estudo teve como objetivo avaliar a reconstrução do osso alveolar após extração em 12 pacientes com perda da tábua óssea vestibular em dentes na região anterior da maxila usando a técnica da reconstrução alveolar proteticamente guiada (RAPG). Na RAPG, uma prótese parcial fixa provisória (PPFP [convencional ou adesiva]) com um pôntico com design específico mantém o coágulo numa posição mecanicamente estável. Além disso, o design do pôntico, com formato de ampulheta e localizado na área subgengival, também previne o colapso das margens gengivais. A recessão gengival foi avaliada durante o período de cicatrização de 6 meses. Tomografias computadorizadas cone beam (TCCB) foram feitas 1 mês antes e 8 meses após o tratamento com a RAPG. Para o desfecho primário, nas imagens panorâmicas, a área central do defeito ósseo em cada dente foi selecionada para as medições lineares. As medições do ganho vertical ósseo vestibular e do ganho em espessura na crista óssea alveolar foram realizadas. A análise estística descritiva e a análise do coeficiente de correlação intraclasse forma realizados. Após o tratamento, todos os pacientes apresentaram formação óssea (ganho vertical médio de 7,1±3,7 mm, associado a ganho horizontal médio de 4,5±1,4 mm na crista óssea alveolar). O coeficiente de correlação intraclasse foi de 0,999. Nenhuma retração gengival acima de 1 mm foi observada. Procedimentos com baixa morbidade sem o uso de biomateriais podem ser úteis na regeneração/preservação do rebordo após as extrações. A RAPG promove a formação do osso alveolar sem o uso de retalhos, enxertos e membranas.

An innovative prostheses design for rehabilitation of severely mutilated dentition: a case report

Partial edentulism has multiple implications in relation to function, esthetics and future rehabilitative treatment. This case report illustrates the management of a patient with extreme consequences of partial edentulism. The main clinical findings were unopposed remaining teeth, overeruption of the remaining teeth, loss of vertical dimension of occlusion, and significant disfigurement of the occlusal plane. Following the diagnostic procedure, a well-coordinated prosthodontic treatment involving liaison with other dental disciplines was indicated. The management involved an innovative combination of fixed and removable prostheses in conjunction with crown lengthening surgery and strategic implant placement. Series of provisional prostheses were applied to facilitate the transition to the final treatment.

Influence of different catilever extensions and glass or polyamaramid reinforcement fibers on fracture strength of implant-supported temporary

In long-term oral rehabilitation treatments, resistance of provisional crowns is a very important factor, especially in cases of an extensive edentulous distal space. The aim of this laboratorial study was to evaluate an acrylic resin cantilever-type prosthesis regarding the flexural strength of its in-balance portion as a function of its extension variation and reinforcement by two types of fibers (glass and polyaramid), considering that literature is not conclusive on this subject. Each specimen was composed by 3 total crowns at its mesial portion, each one attached to an implant component (abutment), while the distal portion (cantilever) had two crowns. Each specimen was constructed by injecting acrylic resin into a two-part silicone matrix placed on a metallic base. In each specimen, the crowns were fabricated with either acrylic resin (control group) or acrylic resin reinforced by glass (Fibrante, Angelus) or polyaramide (Kevlar 49, Du Pont) fibers. Compression load was applied on the cantilever, in a point located 7, 14 or 21 mm from the distal surface of the nearest crown with abutment, to simulate different extensions. The specimen was fixed on the metallic base and the force was applied until fracture in a universal test machine. Each one of the 9 sub-groups was composed by 10 specimens. Flexural strength means (in kgf) for the distances of 7, 14 and 21 mm were, respectively, 28.07, 8.27 and 6.39 for control group, 31.89, 9.18 and 5.16 for Kevlar 49 and 30.90, 9.31 and 6.86 for Fibrante. Data analysis ANOVA showed statistically significant difference (p<0.05) only regarding cantilever extension. Tukey's test detected significantly higher flexural strength for the 7 mm-distance, followed by 14 and 21 mm. Fracture was complete only on specimens of non-reinforced groups.