Treatment of bisphosphonate-related osteonecrosis using platelet-rich plasma: microtomographic, microscopic, and immunohistochemical analyses

Abstract The present study aimed to investigate the use of platelet-rich plasma (PRP) on tooth extraction sites in rats treated with bisphosphonates. Thirty Albinus Wistar male rats were administered 0.035 mg/kg zoledronic acid intravenously for 8 weeks, divided into four administrations with a 2-week interval between each application, after which their upper right central incisors were extracted to induce the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). The samples were divided into the following two groups: Group 1 (G1) underwent marginal resection of BRONJ followed by the use of PRP, while Group 2 (G2) underwent resection of BRONJ but without the use of PRP. The treatment groups were evaluated after 14, 28, and 42 days. Clinical, microtomographic, microscopic, and immunohistochemical (IHC) evaluations were performed. Microtomography results revealed no significant difference between the groups (p <0.05) in any time period. Histomorphometric analysis showed increased bone formation over time for both groups (p < 0.001). G1 demonstrated a greater amount of new bone formation than G2 at 28 and 42 days (p < 0.001), with G1 presenting greater vascularization and a slightly higher VEGF expression. For both groups, RANKL/OPG expression levels were sufficient as a parameter for indicating the rate of bone remodeling in a previously treated area of osteonecrosis groups. Taken together, our findings indicated that the use of PRP improves the resolution process of BRONJ.

Zygomatic implant: late complications in a period of 12 years of experience

ABSTRACT: Purpose Zygomatic implants (ZI) constitute a suitable alternative for treating severe maxillary atrophy. However, a large number of complications associated with ZI have been reported in the literature. This paper presents the late complications associated with ZI during 12 years of experience in the same institution. Materials and methods All cases of ZI from 2000 to 2013 were retrospectively evaluated and the major complications relating to this type of rehabilitation were selected to report. Results The major complications found were: loss of implant, loss of osseointegration, bucco-sinusal communication, fenestration of alveolar mucosa, sinus pathology, and emergency palate fixations. Conclusion The clinical experience of the dental surgeon is critical in the success of zygomatic fixation. Furthermore, there should be careful planning of rehabilitation to reduce the rate of complications.

Metástase oral de adenocarcinoma de cólon: relato de caso / Oral metastasis of colon adenocarcinoma: case report

Introdução: as lesões metastáticas em boca são raras e representam menos de 1% de todas as neoplasias malignas. A mandíbula é a região mais afetada e, os tecidos moles, menos comumente, sendo a gengiva e a língua os sítios mais acometidos. Objetivo: relatar um caso clínico de um paciente portador de adenocarcinoma de cólon avançado sob cuidados paliativos, e que apresentou uma lesão metastática bucal. Método: relado de caso. Resultado e Discussão: O diagnóstico precoce de lesões metastáticas bucais é bastante desafiador para o cirurgião-dentista, uma vez que essas lesões podem manifestar-se clinicamente como lesões reacionais ou neoplasias benignas, que podem dificultar o diagnóstico precoce e seu imediato tratamento. Ressaltamos que o exame físico da boca deve ser realizado em pacientes oncológicos, que apresentam metástases em outros órgãos, no intuito de investigar a existência de lesões bucais e proporcionar um diagnóstico precoce, que possibilite melhor chance de tratamento e reabilitação mais favorável, quando o prognóstico do câncer é bom. Conclusão: nos casos avançados, o tratamento paliativo deve ser realizado para que haja melhor qualidade de vida ao paciente.

Introduction: metastatic lesions in the mouth are rare and account for less than 1% of all malignancies. The jaw is the most affected region, and the soft tissues are less commonly, with the gingiva and tongue being the most affected sites. Objective: the objective of this study is to report a case of a patient with advanced colon adenocarcinoma under palliative care and who presented with an oral metastatic lesion. Method: it is proposed a standard vase report. Result and Discussion: early diagnosis of oral metastatic lesions is quite challenging for the dental surgeon, since these lesions may manifest clinically as reactional lesions or benign neoplasms, which may make early diagnosis and immediate treatment. We emphasize that the physical examination of the mouth should be performed in cancer patients, who have metastases in other organs, in order to investigate the presence of oral lesions and provide an early diagnosis, which allows a better chance of treatment and more favorable rehabilitation, when the prognosis of cancer is good. Conclusion: in advanced cases, palliative treatment should be performed in order to have a better quality of life for the patient.

Current considerations on bone substitutes in maxillary sinus lifting / Consideraciones actuales sobre sustitutos óseos en elevación del seno maxilar

The procedure of maxillary sinus lifting using autogenous bone was considered the reference standard choice for oral rehabilitation in cases of severe atrophic maxilla. However, it is not always a viable option, due to the limitations or morbidity caused by grafting techniques. This has led to the development of bone substitutes, which have been elaborated and improved. Choosing the best biomaterial becomes difficult due to the wide variety of bone substitutes. The aim of this article is to present some of these materials that are reported in the current scientific literature for maxillary sinus lifting.

El procedimiento de elevación del seno maxilar utilizando hueso autógeno se consideraba la opción estándar de oro para la rehabilitación oral en casos de maxilar atrófico grave. Sin embargo, no siempre es una opción viable, debido a las limitaciones o a la morbilidad causada por técnicas de injerto, lo que justifica la existencia de sustitutos óseos que han sido elaborados y mejorados. En cuanto a la amplia variedad de sustitutos óseos, se hace difícil la mejor elección de biomaterial. El objetivo de este informe es presentar una variedad de sustitutos óseos respetados en la literatura científica actual, usados en la elevación del seno maxilar.

Medication-related osteonecrosis of the jaw. Introduction of a new modified experimental model

ABSTRACT PURPOSE : To evaluate a modified experimental model for medication-related osteonecrosis of the jaw (MRONJ) through the upper right central incisor extraction followed by intravenous bisphosphonate administration. METHODS: Forty five rats underwent the upper right central incisor tooth extraction were divided in 2 groups: Group I - experimental group, 30 rats received an intravenous administration protocol of zoledronic acid 35μg/kg into the tail vein every two weeks, totalizing four administrations, during eight weeks of administration, previously the extraction, and Group II - control group, 15 rats didn't received any medication before extraction. The groups were subdivided in postoperative periods: 14/28/42 days. Clinical analysis and microtomography were performed to verify the presence of osteonecrosis. In addition, descritive histological analysis of hematoxylin-eosin stained sections was performed to evaluate the presence of osteonecrosis or necrotic foci. RESULTS: Twelve (40%) rats, from experimental group, showed clinical signs of MRONJ (p=0.005), however, all samples showed imaginologic findings like osteolysis and loss of integrity of the cellular walls (p≤0.001). Microscopic evaluation revealed osteonecrosis areas with microbial colonies and inflammatory infiltrate (p≤0.001). In the control group, all animals presented the chronology of a normal wound healing. CONCLUSIONS: The presence of medication-related osteonecrosis of the jaw after maxillary central incisor extraction in rats. This new experimental model may be considered an option for the study of MRONJ.