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

Micro-CT Evaluation of Root Filling Removal after Three Stages of Retreatment Procedure

The aim of this study was to quantify the residual filling material after filling removal, re-preparation with rotary or reciprocating files and passive ultrasonic irrigation (PUI). Twenty maxillary molars were prepared using ProTaper instruments up to F1. The teeth were filled with AH Plus and ProTaper gutta-percha points using the single-cone technique. Thereafter, the specimens were scanned using a micro-computed tomography system (Micro-CT #1). Then, the root canal filling was removed using ProTaper Retreatment files, and a new scan was performed (Micro-CT #2). The specimens were divided into two groups according to the instrument used for re-preparation: ProTaper rotary or WaveOne reciprocating files (Micro-CT #3). Finally, PUI was performed, and a new micro-CT scan was performed (Micro-CT #4). Intragroup and intergroup analyses were performed using Friedman and Dunn’s post hoc test and the Kruskal-Wallis and Dunn post hoc tests, respectively. Palatal canal presented the highest volume of residual filling material in all stages of endodontic retreatment (p<0.05). The main reduction of filling volume was achieved after using ProTaper Retreament (p<0.05). The amount of remaining filling material after using ProTaper Retreatment was similar to that achieved with rotary and reciprocating files and after PUI (p>0.05). Rotary and reciprocating files achieved similar removal of the root canal filling (p>0.05). The greatest reduction in filling material was achieved after using ProTaper Retreatment files. Rotary and reciprocating instruments and PUI did not improve the removal of root canal filling materials.O objetivo dente estudo foi quantificar o material obturador residual após remoção da obturação, repreparo do canal com instrumentos de rotação contínua e reciprocantes e após irrigação ultrassônica passiva (IUP). Vinte molares superiores foram preparados usando instrumentos ProTaper sequencialmente até F1. Os dentes foram obturados com AH Plus e cones de guta percha ProTaper utilizando a técnica de cone único. Em seguida, os espécimes foram submetidos à microtomografia computadorizada (Micro- CT #1). Então, o material obturador foi removido utilizando instrumentos ProTaper Retratamento e novo escaneamento foi realizado (Micro-CT #2). Os espécimes foram divididos em dois grupos de acordo com o instrumento usado para o repreparo: de rotação contínua (ProTaper) ou reciprocante (WaveOne) (Micro-CT #3). Finalmente, IUP foi realizada e nova micro-CT foi conduzida (Micro-CT #4). As análises intra-grupo e inter-grupos foram realizadas utilizando os testes de Friedman e de Dunn e o teste de Kruskal- Wallis e Dunn, respectivamente. O canal palatino apresentou o maior volume de material obturador remanescente em todos os estágios do tratamento endodôntico (p<0,05). A maior redução do volume da obturação foi obtida após usar os instrumentos ProTaper Retratamento (p<0,05). A quantidade de material obturador remanescente após utilizar instrumentos ProTaper Retratamento foi similar àquela obtida após repreparo com instrumentos de rotação contínua e reciprocantes e após a IUP (p>0,05). Instrumentos de rotação contínua e reciprocantes proporcionaram similar remoção de material obturador (p>0,05). A maior redução do volume de material obturador foi obtida após utilizar os instrumentos ProTaper Retratamento. Instrumentos de rotação contínua e reciprocantes, assim como a IUP, não reduzíram o volume de material obturador remanescente

Representações sociais de saúde bucal entre mães no meio rural de Itaúna (MG), 2002 A social representation study of oral health among mothers in rural areas, Itaúna (MG), 2002

Análise das representações sociais sobre o processo saúde-doença bucal entre 29 mães de escolares residentes no meio rural de Itaúna, em 2002. As entrevistas semi-estruturadas foram transcritas e a análise de conteúdo foi desenvolvida. A análise mostra que as representações sociais sobre saúde-doença estão vinculadas à alimentação e utilização de serviços médicos. Em relação ao processo saúde-doença bucal, identifica-se um discurso associado às normas odontológicas de higiene e dieta. A cárie dentária é vista como uma experiência inevitável, mas a perda dentária, não. Apesar de as condições materiais de vida no meio rural dificultarem a adoção de práticas consideradas favoráveis à saúde bucal, essas mulheres são cobradas em relação ao trabalho de cuidar dos filhos. Essa vivência contraditória causa sentimentos negativos (culpa) e, como conseqüência, queda na qualidade de vida nessa população. Na realidade de vida das entrevistadas, verifica-se que, apesar de as mesmas apresentarem informações sobre o cuidado bucal e desejarem "cuidar dos filhos direito", uma complexa rede de fatores sociais, econômicos, culturais etc., não favorece a promoção de saúde. O planejamento das ações de saúde bucal coletiva deveria levar em consideração não somente dados epidemiológicos quantitativos, mas também as representações sociais sobre saúde bucal.<br>The study evaluated social representation on oral health-illness process between 29 scholarship's mothers in rural areas from Itaúna, in 2002. Semi-structured interviews were transcripted and content analysis was developed. The results have showed that social representation of health-illness was associated with food intake and medical service utilization. Discourse on oral health-illness process was related to dental hygiene and diet rules. Dental caries were an inevitable experience, but tooth loss was not. Despite material conditions of life in rural area have not enabled favorable oral health practices, these mothers were considered responsible for their children oral health care. This contradicted life has caused negative feelings (as guilty) and, consequently, bad quality of life. Respondents have had information about oral home care and they desired to "take care of children well". However, a complex net of social, economic and cultural factors has not favored health promotion. Planning public oral health actions should take in account not only quantitative epidemiological data but social representation of oral health