Histologic and Histomorphometric Analyses of Free Gingival Grafts After Mechanical Expansion: A Study in Dogs.

This study assessed the histologic and histomorphometric changes of free gingival grafts in a canine model after mechanical expansion. A total of eight epithelialized tissue samples were obtained from the palate of eight Beagle dogs. Samples were cut in half and separated into two groups: the test group, in which a device was used to expand the grafts, and the control group, without expansion. After histologic processing, samples were evaluated by qualitative histology and histomorphometry. Histologic analysis revealed some differences in epithelial cell morphology and keratin layer integrity in the test group compared to the control group. Differences in histomorphometric parameters for the expanded and nonexpanded groups, including the thickness of the keratin layer (15.4 ± 13.4 µm and 32.3 ± 18.1 µm, respectively), thickness of the epithelium (398.0 ± 168.0 µm and 368.4 ± 142.8 µm, respectively), and the area occupied by collagen fibers in the connective tissue (62.0% ± 11.0% and 55.8% ± 7.6%, respectively), were not statistically significant (P < .05). Despite some changes in qualitative histology, free gingival grafts maintained their histomorphometric characteristics after mechanical expansion. These data provide a scientific basis for the use of mechanical expansion as a possible procedure to reduce the morbidity of autogenous grafts because a single soft tissue sample can be expanded before grafting. Int J Periodontics Restorative Dent 2023;43:e89-e97. doi: 10.11607/prd.5752.

Bone demineralization promotes superior spread of preosteoblast in culture.

Previous studies have shown substances capable of similar effects of demineralization, accelerating the process of bone remodeling. This study investigated preosteoblasts behavior in cell culture after bone demineralization with citric acid and tetracycline. Seventy-four Wistar rats provided 144 calvarial bone samples, 126 of which were randomly divided in seven groups according to the treatment given to the surface: no demineralization (C), citric acid (CA), tetracycline (TCN) during 15, 30, and 60 s. Each group received preosteoblasts cultured for 24, 48, and 72 hr. Eighteen remaining samples were analyzed for the atomic percentage (A%) by energy dispersive spectroscopy (EDS) before and after demineralization. The average percentage of bone area covered by cells increased with time and it was significantly higher after 24 and 48 hr of culture in groups CA15s, CA30s, CA60s, TCN15s, and TCN30s than in groups TCN60 and C (p < 0.05). The cell morphology in all CA and TCN groups was shown to be compatible with more advanced stages of differentiation than in C group. The A% changed after demineralization. We conclude that demineralization with citric acid or tetracycline for 15-30 s increased the area of bone surface covered by preosteoblasts. The A% changes were not sufficient to impair the cells spreading and morphology. Bone demineralization may promote potential benefits in bone regenerative procedures. HIGHLIGHTS: Low pH effects did not interfere on cell growth. Bone demineralization favored the preosteoblasts growth. A possible alternative to improve graft consolidation.

Viability analysis of subepithelial connective tissue grafts subjected to a mechanical expansion process: a histologic study in dogs.

The aim of this study was to histologically evaluate the viability of mechanically expanded subepithelial connective tissue grafts. Sixteen samples of palatal connective tissue were collected from eight beagle dogs. Half of the samples were subjected to the expansion procedure and used as subepithelial grafts in the canine region, and the samples not subjected to expansion were grafted at the contralateral side. After 60 days, biopsies were collected and examined histologically by light and confocal laser microscopy and immunohistochemically with anti-CD31 antibody for endothelial cells. There were no significant differences between the control and test groups. It was concluded that this new method to expand the area of connective tissue grafts was not only viable biologically, but also decreased surgical risks without increasing processing time.

Obtenção de reosseointegração em implantes acometidos por peri-implantite / Re-osseointegration on implants affected by peri-implantitis: a systematic review

Atualmente, a colocação de implantes osseointegráveis é a primeira escolha para substituir dentes perdidos, portanto, é uma realidade clínica que tem aumentando e juntamente com ela suas complicações. A principal complicação é a peri-implantite que se apresenta como uma infecção bacteriana que afeta os tecidos moles e duros ao redor do implante, promovendo a perda da osseointegração. Essa patologia pode ocorrer devido ao acúmulo de bactérias na superfície do implante, mas o seu desenvolvimento também está relacionado aos indicadores de risco, como história de doença periodontal. Várias terapias são propostas a fi m de minimizar as sequelas deixadas pela infecção peri-implantar. A reosseointegração é um dos objetivos dos vários métodos de tratamento da peri-implantite que, em última análise, pretendem aumentar a previsibilidade dos implantes. Esses métodos podem ser conservadores, incluindo o debridamento da superfície do implante, como também cirúrgicos que são baseados em técnicas regenerativas. Entretanto, não há até o presente momento um consenso a respeito do protocolo ideal para o tratamento da peri-implantite, pois as metodologias são muito variadas e os resultados inconclusivos. Esta revisão abordou um total de 11 estudos em animais com os métodos mais aceitos, chegando à conclusão de que um protocolo definitivo ainda está para ser estabelecido. Contudo, a associação de debridamento mecânico, jato de pó abrasivo, limpeza com ácido cítrico, laserterapia e enxerto ósseo autógeno parece tender a resultados mais promissores.

Currently, the placement of dental implants is the first choice to replace missing teeth; therefore, complications have increased in clinical cases. The main complication is that peri-implantitis presents as a bacterial infection that affects the soft and hard tissue around the implant, promoting loss of osseointegration. This pathology can occur due bacterial accumulation on the implant surface, but its development is also associated to risk factors such as history of periodontal disease. Several therapies are proposed to minimize the consequences of the peri-implant infection. The re-osseointegration is the main goal of the existent treatment methods aiming to improve their predictability. These attempts may be conservative, including implant surface debridement as well as surgical attempts, which are based on regenerative techniques. At present, a consensus regarding the ideal protocol for the treatment of peri-implantitis cannot be established because of the great variability of methodologies and inconclusive results. This systematic review addressed a total of 11 histological studies in animals employing the most acceptable methods and concluded that a protocol is yet to be definitively established. However, the combination of mechanical debridement, abrasive powder, cleaning with citric acid, laser, and autogenous bone grafts tends to reach the most promising results.