Effects of the photobiomodulation using different energy densities on the periodontal tissues under orthodontic force in rats with type 2 diabetes mellitus

Abstract To evaluate the impact of the GaAlAs diode laser with energy densities of 160 J/cm2, 320 J/cm2, and 640 J/cm2 on the periodontal tissues under continuous orthodontic force application and on the rate of orthodontic tooth movement in rats with type-2 diabetes mellitus. The intensity of primary alveolar bone formation was also investigated through the immune-positive osteocytes for OPN antibody. Forty adult male Wistar rats were divided into eight groups of 5 rats: normoglycemic (N), 160 J-laser-normoglycemic (160 J-LN), 320 J-laser-normoglycemic (320 J-LN), 640 J-laser-normoglycemic (640 J-LN), diabetic (D), 160 J-laser-diabetic (160 J-LD), 320 J-laser-diabetic (320 J-LD), and 640 J-laser-diabetic (640 J-LD) rats. Diabetes mellitus was induced by a single intravenous injection of 40 mg/kg monohydrated-alloxan. An orthodontic force magnitude of 20cN was applied. The laser parameters were continuous emission of 780-nm wavelength, output power of 20mW, and fiber probe with a spot size of 0.04 cm in diameter. Radiographic, histomorphological, and immunohistochemical analysis were performed after a period of 21 days. The photobiomodulation using the energy density of 640 J/cm2 strongly stimulated the alveolar bone formation and contributed the reorganization of the soft periodontal tissues, followed by the 320 J/cm2. Extensive alveolar bone loss, intense infiltration of inflammatory cells, and degradation of the PDJ tissue were mainly found in the D and 160 J-LD groups. The rate of orthodontic tooth movement was represented by the interdental distance between the cementoenamel junctions of the right mandibular first and second molars . This distance was larger in the diabetic groups (D: 39.98±1.97, 160 J-LD: 34.84±6.01, 320 J-LD: 29.82±1.73, and 640 J-LD: 35.47±4.56) than in the normoglycemic groups (N: 21.13±1.19; 160 J-LN: 22.69±0.72, 320 J-LN: 22.28±0.78, and 640 J-LN: 24.56±2.11). The number of osteopontin-positive osteocytes was significantly greater in the 640 J-LD (14.72 ± 0.82; p < 0.01) and 640 J-LN (13.62 ± 1.33; p < 0.05) groups than with D (9.82 ± 1.17) and 160 J-LD (9.77 ± 1.10) groups. Therefore, the energy density of 640 J/cm2 provided the best maintenance and integrity of the periodontal tissue microarchitecture under continuous orthodontic force when compared with the other dosages, mainly in the uncontrolled diabetic rats. The interdental distance was greater in the D and 160 J-LD groups due to presence of severe periodontitis caused by diabetes plus the mechanical stress generated by continuous orthodontic forces, implying, thus, an insufficient biostimulatory effect for the dosage of 160 J/cm2.

Cross-sectional assessment of the periapical status as related to quality of root canal fillings and coronal restorations in a Yemeni population

Aim: the present study aimed to examine the influence of the quality of root canal fillings and coronal restorations on the prevalence of periapical lesions. Materials and Methods: Two hundred digital panoramic radiographs were obtained from the archive of Al‑HamziDental Center in Sana’a, Yemen. The final sample consisted of 120 radiographs, and 675 root filled teeth.The quality of root canal fillings was scored according to criteria of length, homogeneity and taper. Coronal status (type of restoration, signs of marginal leakage or decay) was also evaluated. The periapical status was categorized on the basis of presence or absence of radiographical signs of apical periodontitis. Chi-square test was used to determine statistical significance between different parameters. Results: We found that 93.6 percent of root filled teeth were associated with apical periodontitis. Only 9.2 percent of root filled teeth were found to have an acceptable standard of root canal fillings, of which 32.3 percent was also associated to signs of periapical disease. In roots with an unacceptable root canal filling, 95.4 percent had periapical disease. Teeth with good (14.4 percent) and poor (32.9 percent) intra-coronal restorations had apical periodontitis in 93.8 percent and 97.7 percent of cases, respectively. Crown restorations were present in 52.7 percent of root filled teeth, of which 91.0 percent were associated with periapical lesions. Conclusion: The poor technical quality of root canal fillings and coronal restorations is consistent with a high prevalence of apical periodontitis.

Changes in alveolar bone support induced by the Herbst appliance: a tomographic evaluation

ABSTRACT Objective: This study evaluated alveolar bone loss around mandibular incisors, induced by the Herbst appliance. Methods: The sample consisted of 23 patients (11 men, 12 women; mean age of 15.76 ± 1.75 years), Class II, Division 1 malocclusion, treated with the Herbst appliance. CBCT scans were obtained before treatment (T0) and after Herbst treatment (T1). Vertical alveolar bone level and alveolar bone thickness of mandibular incisors were assessed. Buccal (B), lingual (L) and total (T) bone thicknesses were assessed at crestal (1), midroot (2) and apical (3) levels of mandibular incisors. Student's t-test and Wilcoxon t-test were used to compare dependent samples in parametric and nonparametric cases, respectively. Pearson's and Spearman's rank correlation analyses were performed to determine the relationship of changes in alveolar bone thickness. Results were considered at a significance level of 5%. Results: Mandibular incisors showed no statistical significance for vertical alveolar bone level. Alveolar bone thickness of mandibular incisors significantly reduced after treatment at B1, B2, B3, T1 and significantly increased at L2. The magnitude of the statistically significant changes was less than 0.2 mm. The changes in alveolar bone thickness showed no statistical significance with incisor inclination degree. Conclusions: CBCT scans showed an association between the Herbst appliance and alveolar bone loss on the buccal surface of mandibular incisors; however, without clinical significance.

RESUMO Introdução: este estudo avaliou a perda óssea alveolar ao redor dos incisivos inferiores induzida pelo aparelho de Herbst. Métodos: a amostra foi composta por 23 pacientes (11 homens e 12 mulheres; média de idade 15,76 ± 1,75 anos), má oclusão de Classe II, divisão 1, tratados com aparelho de Herbst. TCFCs foram realizadas antes do tratamento (T0) e após o tratamento (T1) com o Herbst. A altura e a espessura óssea alveolar dos incisivos inferiores foram avaliadas. As espessuras ósseas vestibular (V), lingual (L) e total (T) foram mensuradas nos terços cervical (1), médio (2) e apical (3) dos incisivos inferiores. O teste t de Student e o teste t de Wilcoxon compararam as amostras dependentes nos casos paramétricos e não paramétricos, respectivamente. As análises de Pearson e Spearman determinaram a correlação entre as alterações na espessura do osso alveolar. Os resultados foram considerados para um nível de significância de 5%. Resultados: os incisivos inferiores não apresentaram significância estatística para a altura óssea alveolar. Após o tratamento, a espessura óssea alveolar dos incisivos inferiores reduziu-se significativamente em V1, V2, V3 e T1 e aumentou significativamente em L2. A quantidade da alteração óssea significativa foi menor que 0,2mm. As alterações na espessura óssea alveolar não apresentam correlação estatisticamente significativa com o grau de inclinação do incisivo. Conclusões: as imagens de TCFC demonstram associação entre o uso do aparelho de Herbst e a perda óssea alveolar no lado vestibular dos incisivos inferiores; entretanto, sem significância clínica.

Efeito do artefato de "beam hardening" na capacidade de identificação das alterações periodontais e peri-implantares / "Beam Hardening" artefact effect in identifying capacity of periodontal and peri-implant changes

O diagnóstico por imagem é um exame complementar importante para o diagnóstico e acompanhamento da doença periodontal e peri-implantar e atualmente a tomografia computadorizada de feixe cônico (TCFC) substitui o uso das tomografias convencionais odontológicas e da tomografia computadorizada médica. No entanto, artefatos ocorrem principalmente, próximos de estruturas de alta densidade como o metal, sendo que essa alteração pode interferir na interpretação das imagens e no diagnóstico. Sendo assim, o presente estudo tem como objetivo realizar uma revisão de literatura relacionada ao efeito do artefato de "beam hardening" na capacidade de identificação das alterações periodontais e peri-implantares. Conclui-se que a TCFC promove uma avaliação tridimensional de doença periodontal e da peri-implantite, mas na presença de artefatos metálicos pode haver uma limitação da qualidade da imagem do nível ósseo ao redor dos dentes e implantes.(AU)

Diagnostic imaging is an important complementary method for the diagnosis and follow up of periodontal disease and peri-implant and nowadays cone-beam computed tomography (CBCT) replaces the use of conventional dental CT scans and medical CT scan. However, artifacts occur mainly near high-density structures such as metal, and this change may interfere interpretation of the images and diagnosis. Therefore, this study aims to conduct a literature review on the effect of "beam hardening" artifact in identifying capacity of periodontal and peri-implant changes. We conclude that CBCT promote three-dimensional evaluation of periodontal disease and peri-implantitis, but presence of metal artifacts could be a limitation of the image quality of bone level around the teeth and implants.(AU)

An appraisal of periodontal bone loss surgically and by radiovisiography. A comparative study.

The objective of the present study was to conduct a comparative evaluation of periodontal bone loss surgically and by radiovisiography. This study included 26 subjects with 23 mesial and 20 distal sites. Majority of RVG measurements were marginally higher than surgical values. On drawing a comparison between surgical and RVG bone loss, the difference value was statistically significant. On mesial sites, the 't' value was 4.55 with p < .001 and on distal sites 't' value was 2.79 with p < .02. In total 60% of sites showed a difference of < 0.5 mm between RVG and surgical values, 28% of sites showed values between 0.6-1.0 mm and 12% showed a1 mm difference.