Immunohistochemical analysis of growth factors in platelet-rich fibrin membranes.

The use of autogenous materials to promote tissue regeneration has guided the direction of modern dentistry, and platelet-rich fibrin (PRF) is a promising biomaterial for tissue engineering. This in vitro immunohistochemical study aimed to analyze the presence of factors of endothelial growth and cell differentiation in PRF membranes by using the CD31 (endothelial cells) and CD163 (monocytes) markers. Five men and 5 women, aged between 25 and 60 years and without systemic health problems, were enrolled in the study. Blood samples were collected, submitted to a centrifugation protocol, and fixed in 4% formaldehyde, and then immunohistochemical analysis was performed. The histologic analysis of the slides showed that the fibrin clot was formed by a dense fiber network and cells trapped in its structure. One sample was excluded from the markers testing due to poor quality. All 9 of the valid samples were positive for the CD31 and CD163 markers, with reactivity ranging from 5% to 30% and 10% to 40% of cells, respectively. The immunohistochemical analysis showed the presence of CD31 and CD163 in the PRF membranes, indicating the potential for vascular neoformation and the significant presence of monocytes, which play an important role in tissue remodeling via their differentiation into macrophages.

Analysis of the Marginal Fit and Dimensional Stability of Cast-to Cobalt-Chromium Implant Cylinders Cast from Different Alloys.

PURPOSE: To evaluate the influence of cobalt-chromium (Co-Cr) casting alloys' melting temperatures on the cast-to Co-Cr implant cylinders' marginal fit. MATERIALS AND METHODS: Co-Cr alloys with different melting ranges were cast into 20 Co-Cr cylinders: 10 in a high-melting temperature (HMT) group and 10 in a low-melting temperature (LMT) group. Ten cylinders were used as received as a control group. Cylinders' marginal misfit and dimensional stability were evaluated using scanning electron microscopy (×500). RESULTS AND CONCLUSION: HMT cylinders showed significant differences in marginal misfit (2.48 ± 1.07 µm2) compared to LMT (1.53 ± 0.37 µm2) and control (1.27 ± 0.57 µm2) cylinders, but there were no differences in dimensional stability. HMT Co-Cr alloys produce implant-supported prostheses with poor marginal fit.

Evaluation of results of maxillary sinus lifting surgeries using Resorbable synthetic hydroxyapatite

AIM: This study aims to evaluate the results of 10 cases of maxillary sinus lifting using synthetic resorbable hydroxyapatite (osteogen ®) as a filling material. MATERIAL AND METHODS: The surgeries were performed in patients who presented bone resorption in this region. The results were compared radiographically six months after the surgery through initial and final radiographs analysis. RESULTS: The vertical bone height gain was on average 1200.4%, when compared to the initial bone edge. CONCLUSION: The formation of bone tissue in that region had made possible future prosthetic rehabilitation.

Measurement of loosening torque of prosthetic components in Morse taper connection implants

AIM: The aim of this study was to verify two different types of interfaces in Morse taper connection implants, relating the mechanical resistance to a loosening torque that is required to separate or move the prosthetic abutment. MATERIAL AND METHODS: Ten Morse taper connection implants and their respective abutments were divided into two groups (n = 5), DH (double hexagon) interface and OI (octagonal implant) interface. A standard insertion of implants was performed in a stainless steel base, where each abutment received a sequence of two consecutive tightening torques at a 10-minute interval, followed by a loosening torque, which was measured using a digital torque gauge. The Student's t-test with a 5% significance level was used for data analysis. RESULTS: The results showed a statistically significant difference in the loosening torque values compared with DH torque values (p < 0.05). However, the difference between tightening and loosening torque values was not statistically significant in the OI group (p = 0.465). CONCLUSION: The study concluded that there was a difference in the torque required to loosen the abutment screws between the DH group and the OI group, with the latter showing better results.

Evaluation of perception of dental color by students and professors of dentistry

AIM: To evaluate visual perception of dental color carried out by students and professors of Dentistry area. MATERIAL AND METHODS: For this study, 64 people were selected to respond a personal questionnaire and a color selection questionnaire. The respondents also perform, using the color scale VITAPAN classical, the choice of healthy human tooth color, maintained humid and in an acrylic resin cylinder developed especially for this research. RESULTS: Only 6.25% of respondents answered correctly the natural tooth color. CONCLUSION: According to the color verification through a spectrophotometer, only 6.25% of respondents have carried out correctly the color selection. In this way, for the good aesthetical result, the criteria need to be standardized and pre-stablished in order to perform the color selection correctly, observing the variables which can interfere on its choice.

Influence of reverse torque values in abutments with or without internal hexagon indexes.

STATEMENT OF PROBLEM: The mechanical stability of the implant-abutment connection is of fundamental importance for successful implant-supported restorations. Therefore, understanding removal torque values is essential. PURPOSE: The purpose of this study was to evaluate the reverse torque values of indexed and nonindexed abutments of the Morse Taper system. MATERIAL AND METHODS: Twelve Morse taper implants with their respective abutments were divided into 2 groups (n=6): group NI, nonindexed abutments; and group IN, indexed abutments. Each abutment received a sequence of 2 consecutive torques for insertion (15 Ncm) at an interval of 10 minutes, and 1 reverse torque, all measured with a digital torque wrench. The Student t test with a 5% significance level was used to evaluate the data. RESULTS: Statistical analysis showed no significant difference in reverse torque values between nonindexed and indexed abutments (P=.57). When comparing insertion torque and reverse torque values between the groups, group NI presented a mean torque loosening percentage of 8% (P=.013), whereas group IN presented a loosening of 15.33% (P<.001). CONCLUSION: The use of indexed abutments for the Morse taper system presented similar biomechanical stability when compared with nonindexed abutments, both with a significant reduction in reverse torque values.

A method of assessing the effectiveness of the friction fit interface by measuring reverse torque.

STATEMENT OF THE PROBLEM: The connection between abutments and implants is fundamental to successful prosthetic rehabilitation, and the loosening or fracture of the parts are undesirable outcomes. PURPOSE: The purpose of this study was to measure the reverse torque values of 2 different types of Morse taper implants. MATERIAL AND METHODS: Ten Morse taper implants were used, with their respective abutments. They were divided into 2 groups (n = 5): Group DH, implant interface with a double hexagon and Group OI, octagonal implant interface. Each abutment received 2 consecutive insertion torques (32 Ncm) at a 10-minute interval and 1 reverse torque after 5 minutes. The data were analyzed with the Student t test (α= .05). RESULTS: The Student t test demonstrated no significant differences between the values of the insertion and removal torques of the 2 groups (Group DH, P= .22 and Group OI, P= .42) or the removal torque values of the groups (P= .12). CONCLUSION: The results suggest that the strength required to loosen the abutment screws as measured by reverse torque is similar for both a double hexagon interface (DH) and an octagonal interface (OI).

Sobredentaduras e a eficiência mastigatória: revisão da literatura / Overdentures and masticatory efficiency: literature review

A sobredentadura é definida como sendo uma prótese removível parcial ou total que cobre, ou se apoia, em um ou mais dentes naturais ou remanescentes, raízes e/ou implantes dentários. O presente trabalho tem por objetivo comparar a eficiência mastigatória e aceitabilidade pelo paciente das sobredentaduras em relação às próteses totais convencionais. Assim, a partir de uma revisão de literatura, buscou-se mostrar aos cirurgiões-dentistas a importância de tal tratamento protético, principalmente em relação à estética e função proporcionadas aos pacientes

The overdenture is defined as a removable denture partial or total, covering rests of one or more teeth or remaining roots and / or dental implants. This study aims to compare the masticatory efficiency and patient acceptability of overdentures compared to conventional dentures. Thus, from a literature review, we sought to show to dentists the importance of such prosthodontic treatment, especially in relation to aesthetics and function provided to patients

Osteonecrose de mandíbula associada ao uso de bisfosfonato após instalação de implantes: relato de caso / Osteonecrosis of the jaw associated with bisphosphonate use after implant placement: case report

A reabilitação bucal de pacientes com perdas dentárias múltiplas ou unitárias com implantes osseointegrados tem se tornado um tratamento com altas taxas de sucesso. Apesar disso, uma séria complicações pode afetar a sobrevida desses implantes, como a osteonecrose dos maxilares associada ao uso de bisfosfonatos. Os bisfosfonatos são uma classe de medicamentos que têm por função a inibição da atividade dos osteoclastos, interferindo na remodelação e no turnover ósseo. São indicados para retardar o envolvimento ósseo em algumas condições malignas, como em mielomas múltiplos e metástase do câncer de mama e próstata, no tratamento da doença de Paget e da osteoporose. Clinicamente, as BRONJ (Bisphosphonated Related Osteonecrosis of the Jaw) aparecem como perda da continuidade da mucosa bucal com exposição do osso subjacente, podendo ser extremamente dolorosas, persistentes e não responder aos tratamentos convencionais. Assim, o objetivo do presente trabalho é revisar a literatura sobre o tema apresentado e relatar um caso clínico de BRONJ em mandíbula após a fixação de implantes.

Oral rehabilitation of patients with unit or multiple tooth loss with dental implants has become a treatment with high success rates. Nevertheless, a serious complication can affect the survival of these implants: osteonecrosis of the jaws associated with the use of bisphosphonates. Bisphosphonates are a class of drugs that has the function of inhibiting the activity of osteoclasts, interfering with remodeling and bone turnover. Are shown to slow bone involvement in some malignancies such as multiple myeloma and metastatic breast cancer and prostate cancer, in the treatment of Paget's disease and osteoporosis. Clinically the BRONJ appear as loss of continuity of the oral mucosa with exposure of the underlying bone and can be extremely painful, persistent and do not respond to conventional treatments. The objective of this paper is to review the literature on the subject and report of a case in BRONJ after implant fixation.

Implante dentário unitário imediato / Immediate unitary dental implant

O presente estudo trata-se de uma revisão de literatura a respeito de Implante Dentário Unitário Imediato e também uma revisão atualizada com critérios de inclusão pré-estabelecidos relatando taxas de longevidade do ano de 1999 a 2009, bem como procedimentos clínicos associados a sua instalação. Foi realizada uma revisão de literatura com busca de artigos científicos na base de dados MEDLINE e os critérios de inclusão dos mesmos foram: artigos publicados de 1999 a 2009; ensaios clínicos randomizados e não-randomizados; estudos de coorte; estudos de caso-controle; relatos de casos clínicos com um número mínimo de 10 casos; taxas de sucesso e de longevidade devem ter um período de proservação de pelo menos 6 meses; relatos de casos clínicos somente com instalação de implantes imediatos. Foram identificados um total de dez estudos que preenchiam os critérios de seleção desta revisão. Eles relatam as taxas de longevidade de implantes imediatos e alguns ainda comparam com implantes tardios. O período de observação dos mesmos foi de seis meses a seis anos. Na presente revisão, a maior parte dos estudos apresentaram taxas de longevidade de implantes imediatos acima de 90%, ou seja, similar aos implantes colocados em alvéolos cicatrizados. Os autores não encontraram diferenças estatísticas significantes nas taxas de longevidade para técnicas de colocação imediata e tardia. A taxa de longevidade de implantes imediatos foi de 100% em quatro estudos. Dois estudos apresentaram maior taxa de sucesso com colocação imediata (96,8%) quando comparada com a tardia (93,9%). As menores taxas encontradas foram a de 89,3% e 85%. Com isso, os autores concluem que a técnica de instalação de Implante Unitário Imediato é uma técnica confiável e segura apresentado taxas de sucesso semelhante a implantes tardios

The present study is about a literature review regarding it Implants Dental Unitary Implants Immediate and an updated revision with inclusion criteria prestablished showing rates of longevity of the year from 1999 to 2009 as well as associated clinical procedures at its installation. A literature review was accomplished with a research of scientific MEDLINE database and the inclusion criteria of it were: Published from 1999 to 2009 ; randomized and non-randomized clinical rehearsals; cohort studies; case-control studies; reports of clinical cases with a minimum number of 10 cases; success and longevity rates should have a post accompaniment period of at least 6 months; reports of clinical cases only with placement of immediate implants. Ten studies that fitted out the criteria of selection of this revision were identified. They report the longevity rates of immediate dental implants and some still compare to late dental implants. The observation time was from six months to six years. In the present revision, most of the studies presented longevity rates of its immediate implants above 90%, in other words, similar to the implant placed in scarred alveoli. The authors didn’t find significant statistical differences in the longevity rates for techniques of immediate and late placement. The longevity rate of its immediate implant was 100% in six studies. Two studies presented larger success rate with immediate placement (96,8%) when compared with the late (93,9%). 89,3% and 85% were the lowest rates among reported ones, were found in two studies. Thus, we can conclude that the placement technique of it Immediate Unitary Dental Implants is a reliable technique and it holds presented rates of similar success to late implants