Ridge Preservation After Maxillary Third Molar Extraction Using 30% Porosity PLGA/HA/ß-TCP Scaffolds With and Without Simvastatin: A Pilot Randomized Controlled Clinical Trial.

OBJECTIVE: To evaluate clinically and radiographically, in humans, the healing of maxillary third molars postextraction sockets after application of different ridge preservation techniques 3 months after tooth extraction. MATERIALS AND METHODS: Twenty-six sockets (13 patients) were randomly assigned to 4 treatment modalities: deproteinized bovine bone mineral with 10% collagen (DBBM-C), poly(D,L-lactide-co-glycolide) with hydroxyapatite/ß-TCP scaffold (PLGA/HA), PLGA/HA/ß-TCP with 2.0% simvastatin scaffold (PLGA/HA/S), and spontaneous healing (control). Clinical complications were assessed, and cone-beam computed tomographies were taken in 5 patients 3 months after surgeries. For statistical purposes, the Fisher exact test was used (P < 0.05). RESULTS: After 3 months, 6 of 9 grafts from the PLGA/HA group were lost (P < 0.05). PLGA/HA/S' loss was only 2 of 8 (P > 0.05), but no loss was observed in the DBBM-C group. Pain was present in 3 of 8 sites that lost the graft (37.5%) (P > 0.05) and infection in 1 of 8 (12.5%) (P > 0.05), with these only occurring in the PLGA/HA group. CONCLUSIONS: Poly (D, L-lactide-co-glycolide) with hydroxyapatite/ß-TCP (PLGA/HA/ß-TCP) scaffolds, with and without simvastatin, failed to obtain the initial expected results and presented more complications. Scaffolds with simvastatin showed to be superior, with less clinical complications than scaffolds without simvastatin.

Planning of dental implant size with digital panoramic radiographs, CBCT-generated panoramic images, and CBCT cross-sectional images.

OBJECTIVES: To compare the implant size (width and length) planned with digital panoramic radiographs, cone beam computed tomography (CBCT)-generated panoramic views, or CBCT cross-sectional images, in four implant systems. MATERIAL AND METHODS: Seventy-one patients with a total of 103 implant sites in the upper premolar and/or lower molar regions were examined with digital panoramic radiography (D-PAN) and (CBCT). A metal ball 5 mm in diameter was placed in the edentulous area for the D-PAN. CBCT data sets were reformatted to a 10-mm thick CBCT panoramic view (CBCT-pan) and 1-mm cross-sections (CBCT-cross). Measurements were performed in the images using dedicated software. All images were displayed on a monitor and assessed by three observers who outlined a dental implant by placing four reference points in the site of the implant-to-be. Differences in width and length of the implant-to-be from the three modalities were analyzed. The implant size selected in the CBCT-cross images was then compared to that selected in the other two modalities (D-PAN and CBCT-pan) for each of the implant systems separately. RESULTS: The implant-to-be (average measurements among observers) was narrower when measured in CBCT-cross compared with both D-PAN and CBCT-Pan. For premolar sites, the width also differed significantly between D-PAN and CBCT-pan modalities. The implant-to-be was also significantly shorter when recorded in CBCT-cross than in D-PAN. In premolar sites, there were no significant differences in implant length among the three image modalities. It mattered very little for the change in implant step sizes whether CBCT-cross was compared to D-PAN or CBCT-pan images. CONCLUSION: Our results show that the selected implant size differs when planned on panoramic or cross-section CBCT images. In most cases, implant size measured in cross-section images was narrower and shorter than implant size measured in a panoramic image or CBCT-based panoramic view.

Three-dimensional assessment of buccal alveolar bone after rapid and slow maxillary expansion: a clinical trial study.

INTRODUCTION: The purposes of this study were to analyze and compare the immediate effects of rapid and slow maxillary expansion protocols, accomplished by Haas-type palatal expanders activated in different frequencies of activation on the positioning of the maxillary first permanent molars and on the buccal alveolar bones of these teeth with cone-beam computerized tomography. METHODS: The sample consisted of 33 children (18 girls, 15 boys; mean age, 9 years) randomly distributed into 2 groups: rapid maxillary expansion (n = 17) and slow maxillary expansion (n = 16). Patients in the rapid maxillary expansion group received 2 turns of activation (0.4 mm) per day, and those in the slow maxillary expansion group received 2 turns of activation (0.4 mm) per week until 8 mm of expansion was achieved in both groups. Cone-beam computerized tomography images were taken before treatment and after stabilization of the jackscrews. Data were gathered through a standardized analysis of cone-beam computerized tomography images. Intragroup statistical analysis was accomplished with the Wilcoxon matched-pairs test, and intergroup statistical analysis was accomplished with analysis of variance. Linear relationships, among all variables, were determined by Spearman correlation. RESULTS AND CONCLUSIONS: Both protocols caused buccal displacement of the maxillary first permanent molars, which had more bodily displacement in the slow maxillary expansion group, whereas more inclination was observed in the rapid maxillary expansion group. Vertical and horizontal bone losses were found in both groups; however, the slow maxillary expansion group had major bone loss. Periodontal modifications in both groups should be carefully considered because of the reduction of spatial resolution in the cone-beam computerized tomography examinations after stabilization of the jackscrews. Modifications in the frequency of activation of the palatal expander might influence the dental and periodontal effects of palatal expansion.

Diagnostic ability of a cone-beam computed tomography scan to assess longitudinal root fractures in prosthetically treated teeth.

INTRODUCTION: This study evaluated the influence of cast-gold posts on the diagnostic ability of a cone beam computed tomography (CBCT) system in assessing longitudinal root fractures. In addition, the influence of gutta-percha and variations in voxel resolution were assessed. METHODS: One hundred eighty endodontically prepared teeth were divided into 3 experimental and 3 control groups and placed in a dry human skull. The teeth in the experimental groups were artificially fractured. Certain experimental and control groups were filled with gutta-percha cones. Other experimental and control groups were filled with cast-gold posts. All the teeth were viewed by using a tomography scan with 2 voxel resolution protocols (0.3-mm and 0.2-mm). A calibrated examiner, blinded to the protocol, assessed the images by using the nominated scan software. RESULTS: The kappa values obtained for intraobserver reproducibility were 0.84 and 0.93 for 0.3-mm and 0.2-mm voxel resolution, respectively. The presence of gutta-percha or posts reduced the overall sensitivity and specificity in both voxel resolutions, but with no significant association. The CBCT specificity values were similar and did not depend on the voxel resolution adopted. In contrast, the sensitivity values were significantly higher for 0.2-mm voxel resolution in nonfilled (P < .05), gutta-percha (P < .001), and overall (P < .001) groups. CONCLUSIONS: The CBCT diagnostic ability was not influenced by the presence of posts or gutta-percha, and the 0.3-mm voxel resolution images were demonstrated not to be a reliable protocol for the investigation of longitudinal root fractures.

Avaliação da reprodutibilidade na identificação de pontos anatômicos obtidos em telerradiografias laterais de crânios secos com e sem identificadores metálicos / Assessment of reproducibility in the identification of anatomical landmarks obtained from lateral cephalogram of dry skulls with and without metal handles

Objetivo: Este estudo “in vitro” avaliou comparativamente as medidas cefalométricas realizadas em telerradiografias laterais de crâniossecos sem e com identificadores metálicos nos pontos anatômicos.Materiais e métodos: Foram utilizados10 crânios secos para a realização de 20 telerradiografias divididas em dois grupos: 10 telerradiografias com identificadores metálicos nos pontos anatômicos (padrão-ouro) e 10 sem identificadores. Um especialista em radiologia odontológica, treinado e calibrado, realizou os traçadoscefalométricos nos dois grupos. As comparações das medidas foramrealizadas por meio do teste t pareado e coeficiente de repetibilidade de Bland&Altman. Resultados: Os resultados mostraram existir diferençasestatisticamente significativas, pela avaliação do coeficiente derepetibilidade, entre os valores de algumas medidas realizadas sobre as telerradiografias com os identificadores metálicos (padrão-ouro) daquelas realizadas na ausência destes.Conclusão: Pode-se concluir que, mesmo treinado e calibrado, o profissionalpode gerar valores incorretos para os fatores cefalométricos. Assim, a calibragem intra-examinador não reflete a certeza do acerto, e sim a repetição de erros.

Objectives: This study evaluated cephalometric measurements fromlateral chephalograms of dry skulls with and without metal points on anatomical landmarks. Materials and methods: Ten dry skulls were used for the acquisitionof twenty radiographs divided into two groups: ten radiographs with metal points on anatomical landmarks (gold standard) and ten without the identifiers. A specialist in oral radiology, trained and calibrated, carried out the cephalometric analysis in both groups. Comparisons were performed using paired t-test and Bland & Altman coefficient of repeatability. Results: The results of repeatability coefficient showed statistically differences in some cephalometric measurements performed in cephalograms without the metal markers. Conclusion: An examiner, even if calibrated, is subject to errors incephalometric measurements. Therefore, the intra-examiner calibration may not reflect certainty of accuracy but the repetition of errors.