Extrusão cirúrgica de um dente com fratura coronorradicular: acompanhamento de 3.5 anos / Surgical extrusion of a crown-root fractured tooth: 3.5-year follow-up

Introdução: diferentes abordagens de tratamento sãoindicadas para dentes com fraturas coronorradiculares.A extrusão cirúrgica é um procedimento único, que envolveo reposicionamento imediato do dente à sua posiçãonormal. Objetivo: o objetivo deste relato de casofoi apresentar o tratamento multidisciplinar de um pré--molar superior com fratura coronorradicular. Métodos:neste caso, um pré-molar superior fraturado foi tratadopor meio da técnica de extrusão cirúrgica. Após aresolução da lesão periapical, o dente foi restauradocom coroa metalocerâmica. Resultados: após 3,5 anosde acompanhamento, o dente não apresentou sintomasou sinais clínicos e radiográficos de reabsorção radicularprogressiva, de perda óssea marginal ou de doença periapical.Conclusão: os resultados favoráveis do casodemonstram que a extrusão cirúrgica pode ser uma alternativade tratamento para os protocolos existentes.

Comparison of the intrusive effects of miniscrews and utility arches.

INTRODUCTION: The aim of this prospective study was to compare the effects of incisor intrusion obtained with the aid of miniscrews and utility arches. METHODS: Twenty-four patients (10 male, 14 female) with a deepbite of at least 4 mm were divided to 2 groups. In group 1, 13 patients (3 male, 10 female; mean age, 20.90 ± 7.12 years) in the postpubertal growth period were treated by using miniscrews; in group 2, 11 patients (7 male, 4 female; mean age, 15.25 ± 3.93 years) were treated with utility arches. Lateral cephalometric headfilms were taken at the beginning of treatment and after intrusion for the evaluation of the treatment changes. Statistical analyses of the data were performed with a significance level of P <0.05. RESULTS: Intrusion lasted 6.61 ± 2.95 months for group 1 and 6.61 ± 2.46 months for group 2. The changes in the center of resistance of the incisors were 1.75 ± 0.4 mm (P <0.05) for group 1 and 0.86 ± 0.5 mm (P >0.05) for group 2; the difference between the groups was significant (P <0.05). In the miniscrew group, the incisors were protruded 0.79 ± 1.4 mm (P >0.05) relative to pterygoid vertical and 3.85° ± 2.4° (P >0.05) relative to the palatal plane. In group 2, the incisors showed 3.91 ± 0.7 mm (P <0.05) of protrusion relative to pterygoid vertical and 13.55° ± 2.4° (P <0.05) relative to the palatal plane. The maxillary first molars showed significant distal tipping in group 2 (P <0.05). CONCLUSIONS: Unlike with utility arches, true maxillary incisor intrusion can be achieved by application of intrusive forces close to the center of resistance by using miniscrews with no counteractive movements in the molars.

Maxillomandibular fixation screws for early removal of hardware and correction of lingual tilting in alveolar distraction osteogenesis.

Alveolar distraction osteogenesis is a well-known technique used for the management of deficient alveolar ridges. Vector control of the transport segment is the main problem during distraction. This article describes a new technique for early removal of distractor and correction of tilted transport segment in partially edentulous patients.

Comparison of stability of resorbable and titanium fixation systems by finite element analysis after maxillary advancement surgery.

In this study, three-dimensional modeling and finite element analysis were used to evaluate and compare the stability of Le Fort I osteotomy fixed with titanium and resorbable fixation systems under molar and incisor bite forces. A three-dimensional model of 5-mm advanced hemimaxilla was generated. Contact analyses between the upper and lower segments were prescribed. Two L-plates were inserted on this model via simulation. Displacement, principal stresses, and principal elastic strains were evaluated under 44-N, 125-N incisor and, 250-N molar bite forces. These results suggest that Le Fort I osteotomies fixed with titanium miniplates and screws were stable under all tested forces. However, in resorbable group, under incisor bite forces greater than 44 N, there is a great risk of plate fracture, screw deformation, and/or failure.

Miniscrews for upper incisor intrusion.

The aim of this study was to investigate if true incisor intrusion can be achieved using miniscrews. Eleven patients (three males and eight females; mean age: 19.8 +/- 4.8 years) with normal vertical dimension showing a pre-treatment deep bite of 5.9 +/- 0.9 mm and a 'gummy' smile were enrolled in the study. After levelling of the maxillary central and lateral incisors with a segmental arch, an intrusive force of 80 g using closed coil springs was applied from two miniscrews placed between the roots of the lateral and canine teeth. The amount of incisor intrusion was evaluated on lateral cephalometric headfilms taken at the end of levelling (T1) and at the end of intrusion (T2). Statistical analysis of the data was performed using a paired t and Wilcoxon signed rank tests. A significance level of P < 0.05 was predetermined. The mean upper incisor intrusion was 1.92 mm and the mean overbite decrease 2.25 +/- 1.73 mm in 4.55 months. Upper incisor angulation resulted in a 1.81 +/- 3.84 degree change in U1-PP angle and a 1.22 +/- 3.64 degree change in U1-NA angle. However, these were not statistically significant (P > 0.05). True intrusion can be achieved by application of intrusive forces close to the centre of resistance using miniscrews. However, studies with a larger number of subjects and long-term follow-up are necessary.

Treatment of horizontal root-fractured maxillary incisors--a case report.

Traumatic dental injuries often occur to the teeth and their supporting tissues and they are the main reasons for emergency visit to a dental clinic. Management of a fracture depends on its position and the extent of root involvement. Horizontal root fractures are not seen frequently and the treatment consists of reduction and long-term rigid fixation of the coronal segment. The present case demonstrates the successful management of two horizontally fractured maxillary central incisors with a follow-up period of 9 months.

Alveolar distraction osteogenesis versus autogenous onlay bone grafting for alveolar ridge augmentation: Technique, complications, and implant survival rates.

The aim of this study was to define the techniques and compare the complications and implant survival rates in localized alveolar deficiencies reconstructed by alveolar distraction osteogenesis (ADO) or autogenous onlay bone grafting (ABG). Thirty-six patients were treated with ADO or ABG harvested from the mandibular ramus. Twenty-four distractions in 22 patients (ADO group) and 18 ramus grafts in 14 patients (ABG group) were performed. Complications and implant survival rates were evaluated. The overall complication rates were 66.8% and 38.8% in the ADO and the ABG groups, respectively. Implant survival rates were 91.4% and 93.7% in the ADO and the ABG groups, respectively. The complication rate was higher in the ADO group, but the complications were mainly minor, and management was easier in this group than in the ABG group. Although follow-up was shorter, the implant survival rate was slightly higher in the ABG group compared with ADO group.

Stability of zygomatic plate-screw orthodontic anchorage system: a finite element analysis.

OBJECTIVE: To evaluate the biomechanical properties of a standard and a newly designed plate-screw orthodontic anchorage system. MATERIALS AND METHODS: A three-dimensional model of the posterior maxilla, including the zygomatic buttress region, was prepared. Insertion of standard and newly designed plates was simulated on the three-dimensional model. The effect of 200 g of orthodontic force on the plate, screws, and zygomatic bone was evaluated in three-dimensional models by finite element analysis. To determine the force distribution, Von Mises stress, principal maximum and minimum stress, and principal maximum and minimum elastic strain values were evaluated. RESULTS: In all plate models the highest stresses occurred on the threaded bone site where the force application unit was attached. CONCLUSION: Changing the plate configuration did not affect the stress distribution in the newly designed plates. To equalize the force distribution, new plate designs that change the location of the force application unit are required.

Unexpected breakage of mandibular midline distraction device: case report.

Management of the transverse mandibular deficiency and anterior crowding by mandibular midline distraction osteogenesis (MMDO) is an efficient and stable alternative to orthodontic mechanics with minor complications. Although the only major complication reported previously during MMDO is the nonunion of the segments, in the present case report an unexpected breakage of the distractor in MMDO during the consolidation period as a new major complication was presented.