João Batista César Neto

Smoking and periodontal tissues: a review

The impact of smoking on general health has been widely studied and is directly related to several important medical problems including cancer, low birth weight, and pulmonary and cardiovascular disease. In the past 25 years, there has also been an increasing awareness of the role of cigarette consumption in oral health problems such as periodontal disease. Smoking is considered the major risk factor in the prevalence, extent and severity of periodontal diseases. This article will discuss the available evidence and provide the reader with an overview of the impact of smoking and its cessation on the pathogenesis and treatment of periodontal diseases.

Assessment of linear measurements of bone for implant sites in the presence of metallic artefacts using cone beam computed tomography and multislice computed tomography

The objective was to evaluate the influence of dental metallic artefacts on implant sites using multislice and cone-beam computed tomography techniques. Ten dried human mandibles were scanned twice by each technique, with and without dental metallic artefacts. Metallic restorations were placed at the top of the alveolar ridge adjacent to the mental foramen region for the second scanning. Linear measurements (thickness and height) for each cross-section were performed by a single examiner using computer software. All mandibles were analysed at both the right and the left mental foramen regions. For the multislice technique, dental metallic artefact produced an increase of 5% in bone thickness and a reduction of 6% in bone height; no significant differences (p>0.05) were detected when comparing measurements performed with and without metallic artefacts. With respect to the cone-beam technique, dental metallic artefact produced an increase of 6% in bone thickness and a reduction of 0.68% in bone height. No significant differences (p>0.05) were observed when comparing measurements performed with and without metallic artefacts. The presence of dental metallic artefacts did not alter the linear measurements obtained with both techniques, although its presence made the location of the alveolar bone crest more difficult.

Cigarette smoke inhalation modulates gene expression in sites of bone healing: a study in rats

OBJECTIVE The aim of this study was to assess the effect of cigarette smoke inhalation (CSI) on gene expression in alveolar bone healing sites. STUDY DESIGN Wistar rats were randomly assigned to the groups: control [animals not exposed to CSI (n = 20)] and test [animals exposed to CSI, starting 3 days before teeth extraction and maintained until killing them (n = 20)]. First mandibular molars were bilaterally extracted, and the expression of alkaline phosphatase, bone morphogenetic protein (BMP) 2 and 7, receptor activator of nuclear factor κB ligand, osteoprotegerin, and d2 isoform of vacuolar adenosine triphosphatase V(0) domain were assessed by quantitative polymerase chain reaction in the newly formed tissue in the sockets. RESULTS Overall, data analysis demonstrated that CSI significantly affected the expression pattern of all of the studied genes except BMP-7. CONCLUSION The expression of key genes for bone healing may be affected by CSI in tooth extraction sites.

Release of cytokines by stimulated peripheral blood mononuclear cells in chronic periodontitis

OBJECTIVE The emergence of periodontal medicine increased interest in defining the behaviour of peripheral blood cells in periodontitis subjects in comparison with healthy group. The aim of this study was to evaluate the levels of interleukin (IL)-8, tumour necrosis factor-α (TNF-α), IL-6 and IL-10 released by Escherichia coli lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMC) obtained from the peripheral blood of chronic periodontitis subjects. DESIGN PBMC samples were isolated from 19 systemically healthy donors, divided into generalized chronic periodontitis (n=10) and healthy (n=9) subjects. Cells were incubated for 24-48 h in 500 μL wells containing RPMI 1640 and stimulated with 1.0 ng/mL of E. coli LPS. Supernatants were used to quantify the amounts of IL-8, TNF-α, IL-6 and IL-10 released using enzyme-linked immunosorbent assay (ELISA). RESULTS PBMC cells from periodontitis subjects released higher levels of TNF-α and IL-6 than those from healthy subjects (P<0.05). Conversely, the supernatants of the stimulated PBMC cells obtained from healthy subjects presented higher amounts of IL-8 than those from periodontitis (P<0.05). No differences were observed in the levels of IL-10 (P>0.05) between groups. CONCLUSION In conclusion, the results of the present study showed that E. coli LPS-stimulated PBMC from subjects with periodontitis present a different pattern of cytokine release when compared to PBMC from healthy subjects. This phenomenon could have implications locally, in periodontitis, as well as in systemic diseases.

Early flaring and crown-down shaping influences the first file bind to the canal apical third.

The determination of the apical constriction, its diameter and correct cleaning are significant for the biological response in the critical apical zone. Kerekes and Tronstad evaluated morphometrically molars and reported a wide variation of constriction sizes. Additionally, the continuous cement deposition on the constriction throughout life alters its shape and size. There is a wide variation in the canal apical diameter in all tooth groups what hinders the decision making of how much to enlarge the canals. Frequently, the first file to bind does not reflect the apical canal diameter. Clinically, the estimative of the apical diameter is not precise even with the adjunct use of radiographs or electronic apex locators. Stabholz et al. demonstrated that early flaring is critical to tactile determination of the apical diameter. Without early flaring the apical diameter was determined in only 32.3% of the cases, while after this procedure the determination increased to 75%. Therefore, the tactile sensitivity determines more accurately the number of instruments required for the enlargement of the apical region. In spite of this, the tactile sensitivity does not determine whether the instrument is bound just at the constriction zone or if interferences along the root canal are negatively influencing the apical binding. Leeb and Philippas reported that the normal dentin deposition promotes the root canal constriction and narrows the cervical region in molars. Irregularities of the walls and/or curvatures of the root canal can exert a pressure against the file and interfere with the practitioner’s ability to determine whether the binding occurred at the apical region. The

Impact of Cannabis Sativa (Marijuana) Smoke on Alveolar Bone Loss: A Histometric Study in Rats

BACKGROUND Cannabis sativa (marijuana) can interfere with bone physiopathology because of its effect on osteoblast and osteoclast activity. However, its impact on periodontal tissues is still controversial. The present study evaluates whether marijuana smoke affects bone loss (BL) on ligature-induced periodontitis in rats. METHODS Thirty male Wistar rats were used in the study. A ligature was placed around one of the mandible first molars (ligated teeth) of each animal, and they were then randomly assigned to one of two groups: control (n = 15) or marijuana smoke inhalation ([MSI] for 8 minutes per day; n = 15). Urine samples were obtained to detect the presence of tetrahydrocannabinol. After 30 days, the animals were sacrificed and decalcified sections of the furcation area were obtained and evaluated according to the following histometric parameters: bone area (BA), bone density (BD), and BL. RESULTS Tetrahydrocannabinol was positive in urine samples only for the rats of the MSI group. Non-significant differences were observed for unligated teeth from both groups regarding BL, BA, and BD (P >0.05). However, intragroup analysis showed that all ligated teeth presented BL and a lower BA and BD compared to unligated teeth (P <0.05). The intergroup evaluation of the ligated teeth showed that the MSI group presented higher BL and lower BD (P <0.05) compared to ligated teeth from the control group. CONCLUSION Considering the limitations of this animal study, cannabis smoke may impact alveolar bone by increasing BL resulting from ligature-induced periodontitis.

In vivo comparison of the accuracy of two electronic apex locators.

The aim of this study was to analyse in vivo the accuracy of two apex locators, Root ZX and Novapex, to determine the position of the apical constriction. Twenty-three human single-rooted teeth to be extracted for periodontal reasons constituted the experiment. Endodontic access was obtained and the apical constriction was determined by one of the apex locators after initial crown-down preparation. When the electronic marker indicated that the tip of the endodontic file was at the apical constriction, the teeth were filled with composite and then surgically removed. The presence of the endodontic file tip at the apical constriction was evaluated stereomicroscopically (30×) and confirming radiographs were exposed. The accuracy of Root ZX and Novapex was 91.7% and 81.8% respectively. Within the limits of this study, the evaluated apex locators have a similar clinical performance for the apical constriction location.

Odontoplasty associated with clinical crown lengthening in management of extensive crown destruction.

Aim: The aim of this study was to evaluate the clinical outcome of teeth submitted to odontoplasty during clinical crown lengthening surgery (CCLS), when compared to their contralateral non-operated teeth. Materials and Methods: Fourteen patients submitted to odontoplasty during CCLS were evaluated according to plaque index, bleeding on probing, probing depth and final restoration outcome (total success, relative success and failure). Results: The mean follow-up period was 13.57 (± 8.00) months, and ranged from 6 to 24 months. Twelve cases presented total success of the final rehabilitation and 2 cases presented relative success. The cases of relative success were due to the necessity for a new periodontal intervention (scalling). No differences were observed with respect to periodontal parameters (P>0.05) and the patients that showed relative success presented generalized poor oral hygiene. Conclusions: The odontoplasty during clinical crown lengthening surgery is a feasible procedure in the management of extensive crown destruction.

Expression of Protease Activated Receptor-1 in Chronic Periodontitis

BACKGROUND Protease activated receptor-1 (PAR1) activation by thrombin may play a role in repair and homeostasis of periodontal tissues. The main objective of this study is to investigate PAR1 expression in patients with periodontitis, before and after non-surgical periodontal treatment, and to associate its expression with the presence of inflammatory biomarkers and PAR2 expression. METHODS Gingival crevicular fluid (GCF) samples and clinical parameters, including probing depth, clinical attachment level, bleeding on probing, and gingival and plaque indices, were collected from periodontally healthy individuals and patients with moderate chronic periodontitis (CP) before and 6 weeks after periodontal non-surgical treatment. PAR1 and PAR2 messenger RNA (mRNA) at the GCF were evaluated by quantitative polymerase chain reaction (qPCR). Flow cytometry analysis identified the GCF PAR1-expressing cells. GCF inflammatory biomarkers were also determined. RESULTS Clinical parameters were significantly improved after therapy (P <0.01). The qPCR analysis showed that, before therapy, PAR1 mRNA levels in CP were similar to controls. Periodontal treatment led to increased PAR1 expression in CP (P <0.05). PAR1 expression was inversely correlated to PAR2 expression and with interleukins 6 and 8, tumor necrosis factor-α, interferon-γ, and matrix metalloproteinase-2 levels. CONCLUSIONS Periodontal treatment results in PAR1 overexpression in the GCF, and PAR1 expression is associated with decreased expression of inflammatory biomarkers and inversely correlated to PAR2 expression in the GCF. Therefore, the data suggest the importance of PAR1 mediating the known anabolic actions of thrombin in the periodontium.

A influência do sexo e da idade na prevalência de bolsas periodontais

Este trabalho teve como objetivo avaliar a influencia dos fatores de risco na prevalencia de bolsas periodontais em pacientes atendidos na clinica do terceiro e quarto anos da Faculdade de Odontologia de Piracicaba - Unicamp. Foram avaliados 100 pacientes atraves do levantamento dos dados contidos nas fichas clinico-anamnesicas, sendo consideradas bolsas de profundidade: 3 mm, 5 mm, 7 mm e 10 mm, de acordo com o sistema diagnostico WS (SALLUM; SALLUM27, 1996). Os resultados foram comparados entre as profundidades de sondagem e as variaveis idade, sexo, bem como sua distribuicao por sextantes. Observou-se maior prevalencia de bolsas periodontais no sexo masculino, bem como maior profundidade de sondagem em pacientes acima de 31 anos. A distribuicao de bolsas periodontais entre os sextantes foi homogenea.