Release of leachable products from resinous compounds in the saliva of children with anterior open bite treated with spur

Abstract To evaluate the release of bisphenol-A glycidyl methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), bisphenol A (BPA), and phthalates of the composite resin used in the bonding of spurs applied in the treatment of children with anterior open bite and its effects on human keratinocytes. Methodology Saliva samples of 22 children were collected before spur attachment (baseline) and 30 minutes (min) and 24 hours (h) after spur bonding. Analysis was performed using high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (HPLC-MS/MS) and gas chromatography coupled to mass spectrometry (GC-MS). Standardized resin increments were added to three different dilutions of the cell culture medium. Keratinocytes (HaCaT) were cultivated in the conditioned media and evaluated for cell viability (MTT) and cell scratch assay. Results The levels of BisGMA (1.74±0.27 μg/mL), TEGDMA (2.29±0.36 μg/mL), and BPA (3.264±0.88 μg/L) in the saliva after 30 min, in comparison to baseline (0±0 μg/mL, 0±0 μg/mL, and 1.15±0.21 μg/L, respectively), presented higher numbers. After 24 h, the levels of the monomers were similar to the baseline. Phthalates showed no significant difference among groups. HaCat cells showed increased viability and reduced cell migration over time after exposure to methacrylate-based resin composites. Conclusion Resin composites, used to attach spurs in children with anterior open bite during orthodontic treatment, release monomers after polymerization and can influence the behavior of human keratinocytes, even at very low concentrations. Orthodontists should be aware of the risks of the resinous compounds release and preventive procedures should be held to reduce patient exposure.

Avaliação da alteração de cor de uma resina composta "beautiful bulk" submetida à imersão em soluções pigmentantes / Color change evaluation of a composite resin "beautiful bulk" submitted to immersion in pigmentant solutions

Objetivo:O objetivo do estudo foi verificar, in vitro, a alteração de cor da resina composta Beautiful-Bulk®, exposta aos líquidos pigmentantes. Métodos:Foram confeccionados 60 espécimes da resina (15,0 mm de diâmetro e 1,0 mm de espessura, n = 5) nas cores A2, B2 e C2. Os espécimes foram mantidos em uma sala escura por sete dias, em ambiente seco, a 37 °C e, em seguida, foram fotografados com aparelho celular iPhone 6S®. Os espécimes foram divididos aleatoriamente e submetidos a ciclos de imersão em quatro líquidos: água destilada (controle), suco de açaí, Coca-Cola® e molho de tomate. As imersões foram realizadas em sete e quatorze dias de forma cíclica, após a confecção dos espécimes, três vezes ao dia, durante 20 minutos. Ao fim de cada ciclo, novas fotografias foram realizadas. As imagens foram analisadas no programa Adobe Photoshop® e os dados convertidos em L*a*b através de um histograma. A variação de cor (∆E) foi analisada pela escala CIE-Lab. Resultados:A análise dos resultados (One-way ANOVA, Teste de Tukey, p < 0,05) demonstrou que o grupo controle produziu maior alteração de cor (p < 0,05) em sete e quatorze dias na cor A2. A cor B2, no ciclo de quatorze dias, apresentou maior alteração de cor (p < 0,05) para os espécimes imersos em molho de tomate sem diferença estatística (p > 0,05) do controle. Para a cor C2, os espécimes imersos em molho de tomate tiveram maior alteração de cor (p < 0,05) em sete dias. Conclusão:Conclui-se que todas as substâncias pigmentantes e a água destilada foram capazes de produzir grandes alterações de cor na resina Beautifil Bulk®. Existe uma interação significativa entre a cor da resina e agentes pigmentantes.

Aim: This study sought to verify, in vitro, the color change of the nanoparticle composite resin, Beautiful Bulk®, exposed directly to pigmented liquids. Methods: Sixty test specimens were made in a Metal matrix (15.0 mm X 1.0 mm) using composite resin (n = 5) in colors A2, B2, and C2. The specimens were photographed with a smartphone (iPhone 6S®) seven days after the preparation. The specimens were kept in the dark for seven days, dry, at 37°C. The specimens were then randomly divided and immersed in four liquids: distilled water (control), açaí juice, Coca-Cola®, and tomato sauce. The immersions were performed in seven and fourteen days cyclically, three times a day, for 20 minutes. At the end of each immersion cycle, new photographs were taken with the same smartphone. The images were analyzed in the Adobe Photoshop® program, and the data was converted to L* a* b* through a histogram. The color variation (∆E) was analyzed by the CIE-Lab scale. Results: Analysis of the results (Tukey's test, p < 0.05) showed that the control group produced a greater color change (p < 0.05) in seven and fourteen days in the A2 shade. The B2 shade, in fourteen days, showed a greater color change (p < 0.05) for the specimens immersed in tomato sauce with no statistical difference (p > 0.05) of the control. For the C2 shade, the specimens immersed in tomato sauce presented a greater color change (p < 0.05) at seven days. Conclusion: It could therefore be concluded that there is a significant interaction between the composite resin and pigment agents. All pigmented substances produced color changes in the composite resin.

Dental caries and developmental defects of enamel in individuals with chronic kidney disease: Systematic review and meta-analysis.

OBJECTIVE: To evaluate studies assessing the prevalence of dental caries and developmental defects of enamel (DDE) in individuals with chronic kidney disease (CKD) in comparison with individuals without CKD. MATERIALS AND METHODS: Electronic searches were performed in PubMed, Web of Science, Scopus, Medline via Ovid, and ProQuest databases from their inception date until February 2018. Two review authors independently selected the studies, extracted data, and assessed the methodological quality. Meta-analysis was performed. RESULTS: Twenty-seven studies were included in this study. For permanent teeth, 14 studies found that individuals without CKD had higher dental caries scores than those with CKD. However, only five studies presented results with a statistically significant difference between groups. Among the studies evaluating primary teeth, five showed that individuals without CKD had higher dental caries scores than those with CKD. Five studies showed that individuals with CKD had a significantly higher prevalence of DDE than individuals without CKD. The meta-analyses showed that individuals without CKD had significantly higher scores of dental caries teeth and surfaces than individuals with CKD. For DDE, no statistical difference between groups was observed. CONCLUSIONS: Individuals with CKD present lower dental caries scores and a higher prevalence of DDE in comparison with individuals without CKD.

Rehabilitation with Fixed Prosthodontics Associated with Removable Partial Prosthesis: A 5-Year Follow-Up Clinical Evaluation.

Dental implants are a common and successful option for the rehabilitation of edentulous areas. However, there are some limitations to their use. The present clinical report describes a 5-year follow-up of maxillary rehabilitation using an attachment-retained removable partial denture (RPD) associated with fixed partial denture (FPD) units as an alternative to orthodontic treatment associated with orthognathic surgery and dental implant placement. Rehabilitation with fixed prosthodontics associated with a removable partial prosthesis was proposed. For greater precision and stability, a gold attachment was prepared. The patient was very satisfied with the rehabilitation and has been clinically followed for 5 years. In cases where the use of dental implants and/or conventional FPDs is limited or not indicate the association between an FPD and an RPD by means of attachments remains an important alternative to conventional clasp-retained RPDs.

Physicochemical Properties of a Methacrylate-Based Dental Adhesive Incorporated with Epigallocatechin-3-gallate

This study aimed to evaluate the influence of epigallocatechin-3-gallate (EGCG) incorporation on the physicochemical properties of a methacrylate-based dental adhesive. EGCG was added to Adper Easy One (3M-ESPE) except in control group, to obtain concentrations of 0.01% w/w and 0.1% w/w of EGCG-doped adhesives. For water sorption (WS) and solubility (SL) surveys, resin discs were assayed following ISO recommendations (n=10). The degree of conversion (DC) was analyzed by FTIR whereas flexural strength (FS) was tested by three-point bending with bar specimens (n=10). Data were subjected to one-way ANOVA and Tukey's test (p<0.05). No significant difference in the DC, WS and FS were found between the different concentrations of EGCG (p>0.05). Adhesives containing 0.1% or 0.01% of EGCC demonstrated similar values of SL (p>0.05) and higher than those found for adhesive without EGCC (p<0.05). In conclusion, the addition of EGCC to adhesive reduced the solubility without affecting the other evaluated properties.

Esse estudo teve como objetivo avaliar a influência da incorporação de epigalocatequina-3-galato (EGCG) nas propriedades físico-químicas de um sistema adesivo à base de metacrilato. O EGCG foi adicionado ao Adper Easy One (3M-ESPE), exceto para o grupo controle, para a obtenção das concentrações de 0,01% e 0,1% p/p. No ensaio de sorção (S) e solubilidade (SL), foram confeccionados discos de resina de acordo com as recomendações da ISO (n=10). O grau de conversão (GC) foi analisado através de FTIR, enquanto a resistência flexural (RF) foi avaliada em teste de flexão de três pontos com espécimes em forma de barra (n=10). Os dados foram submetidos à Análise de Variância a um critério e teste de Tukey (p<0,05). Não houve diferença significativa entre as concentrações de EGCG testadas no GC, SL e RF (p>0,05). Adesivos contendo EGCG a 0,1% ou 0,01% apresentaram valores similares de SL (p>0,05) e maiores do que os valores obtidos pelo adesivo não incorporado por EGCG. Conclui-se que a adição de EGCG ao adesivo reduziu a solubilidade sem afetar as outras propriedades avaliadas.

Zinc incorporation improves biological activity of beta-tricalcium silicate resin-based cement.

INTRODUCTION: Matrix metalloproteinase (MMP) inhibition may improve endodontic treatment prognosis. The purpose of this study was to determine if zinc incorporation into experimental resin cements containing bioactive fillers may modulate MMP-mediated collagen degradation of dentin. METHODS: Human dentin samples untreated and demineralized using 10% phosphoric acid or 0.5 mol/L EDTA were infiltrated with the following experimental resins: (1) unfilled resin, (2) resin with Bioglass 45S5 particles (OSspray, London, UK), (3) resin with beta-tricalcium silicate particles (ßTCS), (4) resin with zinc-doped Bioglass 45S5, and (5) resin with zinc-doped ßTCS particles. The specimens were stored in artificial saliva (for 24 hours, 1 week, and 4 weeks) and submitted to radioimmunoassay to quantify C-terminal telopeptide. Scanning electron microscopy analysis was also undertaken on dentin samples after 4 weeks of storage. RESULTS: Collagen degradation was prominent both in phosphoric acid and EDTA-treated dentin. Resin infiltration strongly reduced MMP activity in demineralized dentin. Resin containing Bioglass 45S5 particles exerted higher and stable protection of collagen. The presence of zinc in ßTCS particles increases MMP inhibition. Different mineral precipitation was attained in dentin infiltrated with the resin cements containing bioactive fillers. CONCLUSIONS: MMP degradation of dentin collagen is strongly reduced after resin infiltration of dentin. Zinc incorporation in ßTCS particles exerted an additional protection against MMP-mediated collagen degradation. However, it did not occur in resin containing Bioglass 45S5 particles, probably because of the formation of phosphate-zinc compounds.

Effectiveness of different removal methods of artificially demineralized dentin / Efetividade de diferentes métodos de remoção de dentina desmineralizada artificialmente

Objective: This study aimed to evaluate the effectiveness of different mechanical methods for the removal of demineralized dentin. Methods: Healthy human third molars were prepared in such a way that the flat occlusal surfaces of the dentin were exposed and longitudinally sectioned in a vestibular-lingual direction. One section of each tooth was submitted to the pH-cycling model, while the other section was kept intact. The tooth sections were joined, and a single operator performed dentin removal using a steel bur, a hand instrument,or a polymer bur. The tooth’s sections were then separated, and digital images were obtained. The depth of the prepared cavities and the microhardness measurements were checked and analyzed statistically using the Kruskal-Wallis One-Way ANOVA in Ranks, the Tukey test, while desmineralized dentin were comparedusing the One-Way ANOVA, and the Holm-Sidak method (p < 0.05). Results: The steel bur produced the deepest cavities in mineralized and demineralized dentin. The polymer bur generated the shallowest cavitiesin demineralized dentin. The measurements of microhardness of the deepest surfaces of the cavities prepared in demineralized dentin indicated that the steel bur and hand instrument presented similar values, while those values produced by polymer burs proved to be lower. Conclusion: The effectiveness of the removalof demineralized dentin varied among the three methods used in this study. The polymer bur proved to bethe most conservative of the methods used. By contrast, the steel bur and hand instrument showed a similareffectiveness in the removal of dentin, according to the microhardness of the remaining dentin, even thoughthey produced different cavity depths.

MMPs activity and bond strength in deciduous dentine-resin bonded interfaces.

OBJECTIVES: To determine effect of ageing on deciduous dentine-resin interfaces bond strength and the metalloproteinases (MMPs) activity at the hybrid layer compared to permanent dentine. METHODS: Microtensile bond strength (MTBS) tests were performed in human deciduous and permanent dentine after 24h, 3 and 6 months using an etch and rinse adhesive. C-terminal telopeptide concentrations (ICTP) were calculated, in order to determine MMPs mediated collagen degradation at the hybrid layer. RESULTS: The highest MMPs-mediated collagen degradation values occurred in phosphoric acid demineralized dentine, ICTP values were similar for deciduous and permanent dentine after 1 week. Resin infiltration decreased collagen degradation in both dentins and ICTP values were similar to those attained by for untreated dentine. In resin infiltrated and untreated dentine specimens collagen degradation was always higher for deciduous dentine. At 24h, MTBS was higher in permanent dentine. After ageing MTBS decreased and performed similarly in both dentins. CONCLUSIONS: Higher collagenollytic activity is found in deciduous than in permanent dentine. At 24h, collagen cleavage by MMPs at the hybrid layer is higher in deciduous dentine leading to a lower MTBS. CLINICAL SIGNIFICANCE: The presence of resin monomers reduced collagen degradation when applied on demineralized dentine, but exerted protection was lower in deciduous dentine.

Digital image analysis method to assess the performance of conventional and self-limiting concepts in dentine caries removal.

OBJECTIVE: To assess dentine caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of carbide and polymer burs. METHODS: Sectioned carious molars were photographed. Digital images were taken, before and after caries removal, using a Digital Single Lens Reflex camera. The following regions of interest were measured using visual criteria: Residual Infected Dentine (RI), Residual Affected Dentine (RA), Removal Sound Dentine (RA), Prepared Cavity (PC) and Removed Sound Dentine (RS). CRE was determined on basis of: relative residual infected dentine (RI/II), relative residual carious-affected dentine (RA/IA) and total relative residual dentine (RI+RA/II-IA). MIP was determined on basis of: infected dentine cavity size (PC/II), total relative cavity size (PC/II+IA), and corrected relative cavity size (PC-RS/II+IA). RESULTS: The polymer bur showed the highest preservation of carious-affected dentine after excavation, when the RA/IA ratio was studied. Both kind of burs showed similar values after assessing the RI/II and RI+RA/II-IA ratios. The infected dentine relative cavity size (PC/II) was higher when the carbide bur was used. Both burs attained similar PC/II+IA and PC-RS/II+IA ratios. CONCLUSIONS: Polymer burs accomplished the concept of minimal-invasive dentistry, showing its self-limiting ability. The minimal-invasiveness potential showed that carbide burs resulted in the worst compromise between effective and selective infected-caries removal.

Experimental resin cements containing bioactive fillers reduce matrix metalloproteinase-mediated dentin collagen degradation.

INTRODUCTION: Collagen dentin matrix may represent a suitable scaffold to be remineralized in the presence of bioactive materials. The purpose of this study was to determine if experimental resin cements containing bioactive fillers may modulate matrix metalloproteinase-mediated collagen degradation of etched dentin. METHODS: Human dentin beams demineralized using 10% phosphoric acid or 0.5 mol/L EDTA were infiltrated with the following experimental resins: (1) unfilled resin, (2) resin with Bioglass 45S5 particles (Sylc; OSspray Ltd, London, UK), and (3) resin with ß-tricalcium phosphate-modified calcium silicate cement (HCAT-ß) particles. The filler/resin ratio was 40/60 wt%. The specimens were stored in artificial saliva, and the determination of C-terminal telopeptide (ICTP) was performed by radioimmunoassay after 24 hours, 1 week, and 4 weeks. Scanning electron microscopic analysis of dentin surfaces after 4 weeks of storage was also executed. RESULTS: Collagen degradation was prominent both in phosphoric acid and EDTA-treated dentin. Resin infiltration strongly reduced the MMP activity in demineralized dentin. Resin-containing Bioglass 45S5 particles exerted higher and more stable protection of collagen at all tested dentin states and time points. HCAT-ß induced collagen protection from MMPs only in EDTA-treated specimens. Dentin remineralization was achieved when dentin was infiltrated with the resin cements containing bioactive fillers. CONCLUSIONS: MMP degradation of dentin collagen is strongly reduced in resin-infiltrated dentin. The inclusion of Bioglass 45S5 particles exerted an additional protection of collagen during dentin remineralization.

A ZnO-doped adhesive reduced collagen degradation favouring dentine remineralization.

OBJECTIVES: The objective of the study was to determine the efficacy of a ZnO-doped etch and rinse adhesive in decreasing MMPs-mediated collagen degradation at the resin-dentine hybrid layer, and increasing bonding stability. METHODS: C-terminal telopeptide concentrations (ICTP) were determined after 24h, 1wk and 4wk in human dentine beams. Dentine was treated: (1) 37% phosphoric acid for 15s (PA), (2) PA-etched dentine infiltrated with Single Bond (SB), (3) PA-etched dentine infiltrated with ZnO doped SB (ZnO particles--10wt%--were added to the bonding resin) (ZnO-SB), and (4) Clearfil SE Bond primed-dentine was infiltrated with Clearfil SE bonding resin (CSE). Microtensile bond strength (MTBS) was assessed for the different groups at 24h and after 3months. Debonded dentine surfaces were studied by scanning electron microscopy. RESULTS: MMPs-mediated collagen degradation occurred in demineralized dentine (PA). Resin infiltration decreased collagen degradation. The lowest collagen degradation was found for Zn-doped SB, followed by CSE. When these adhesives were applied, ICTP values did not change throughout the study period. At 24h, similar MTBS was attained for all adhesives. Only SB decreased MTBS after three months. CONCLUSIONS: Addition of ZnO particles to SB produced a reduction in dentine collagen degradation and increased resin-dentine bonds durability. In Zn-doped adhesive interfaces, a calcium phosphate layer and tubular occlusion was encountered at the debonded interface. CLINICAL SIGNIFICANCE: ZnO particles addition into the bonding resin of SB makes a breakthrough to prevent the hybrid layer degradation and to preserve its bonding efficacy overtime.

Bleaching agents increase metalloproteinases-mediated collagen degradation in dentin.

INTRODUCTION: Tooth bleaching is based on hydrogen peroxide application. The Objective of this study was to determine whether dental bleaching agents affect metalloproteinases-mediated dentin collagen degradation. METHODS: Human dentin specimens were subjected to different treatments: (1) untreated dentin; (2) demineralization by 37% phosphoric acid (PA); (3) demineralization by 37% PA, followed by application of Single Bond (SB); (4) 2 immersions of 7 days each in a nonvital bleaching agent, followed by PA; (5) 2 immersions of 7 days each in nonvital bleaching, followed by PA and SB application; (6) 3 immersions by using in-office bleaching gel for 20 minutes; (7) 3 immersions by using in-office bleaching gel for 20 minutes plus activation with a light source; and (8) immersion in home bleaching gel for 8 hours per day during 3 weeks. Specimens were stored in artificial saliva. C-terminal telopeptide determinations (radioimmunoassay) were performed after 24 hours, 1 week, and 4 weeks. RESULTS: Bleaching agents increased collagen degradation, but C-terminal telopeptide of type I collagen (ICTP) values were higher when dentin was PA-demineralized. Nonvital bleaching plus PA promoted the highest collagenolytic activity, which was reduced after SB infiltration. Halogen light application did not influence ICTP values. At 24 hours, home bleaching exhibited high collagenolytic activity, which decreased up to 4 weeks. After 4 weeks of storage, all bleaching procedures showed similar values of collagen degradation, which were not different from those of PA-demineralized and resin-infiltrated dentin. CONCLUSIONS: All tested bleaching agents increase matrix metalloproteinases-mediated collagen degradation in dentin. This effect was not completely reverted after 4 weeks. Home bleaching induced the highest collagen degradation.

Zinc-doped dentin adhesive for collagen protection at the hybrid layer.

The aim of the study was to ascertain whether the addition of zinc to adhesives may decrease metalloproteinase-mediated collagen degradation without affecting bonding efficacy. Human dentin beams were treated with phosphoric acid, with Clearfil SE Bond Primer or with Clearfil SE Bond Primer plus ZnCl(2) (2 wt%). Acid-etched dentin was infiltrated with Single Bond, Single Bond plus ZnCl(2) (2 wt%), or Single Bond plus ZnO nanoparticles (10 wt%), and Clearfil SE Bond-primed dentin was infiltrated with Clearfil SE Bonding resin, Clearfil SE-Bonding resin with ZnCl(2) (2 wt%), or Clearfil SE-Bonding resin with ZnO nanoparticles (10 wt%). The C-terminal telopeptide concentrations were determined 24 h, and 1 and 4 wk after treatment. Microtensile bond strength to dentin was determined for the tested adhesives. Matrix metalloproteinases-mediated collagen degradation occurred in acid-etched and SE-primed dentin. Resin infiltration decreased collagen degradation. Lower collagen degradation was found for SE Bond than for Single Bond. Zinc-doped Single Bond resin always reduced collagen degradation, the ZnO particles being more effective than ZnCl(2) . Zinc-doped SE Bond reduced the liberation of C-terminal telopeptide only at 24 h. Bond strength to dentin was not decreased when Zn-doped resins were employed, except when ZnCl(2) was added to SE Primer. Zinc-doped resin reduced collagen degradation in Single Bond hybrid layers, but did not affect bond strength. The addition of zinc to SE Bond had no beneficial effects.

Effect of dentin etching and chlorhexidine application on metalloproteinase-mediated collagen degradation.

Dentin matrix metalloproteinases (MMPs) are involved in the degradation of collagen in resin-dentin interfaces. This study evaluated whether collagen degradation can be prevented by chlorhexidine digluconate (CHX) after different dentin demineralization procedures. The demineralization of human dentin was performed with phosphoric acid (PA), EDTA or acidic monomers (Clearfil SE Bond and Xeno V). Specimens were stored (for 24 h, or for 1 or 3 wk) in the presence or absence of CHX. In half of the groups, active MMP-2 was incorporated into the storage solution. At the end of each storage period, the C-terminal telopeptide (ICTP) concentration (which indicates the amount of collagen degradation) was measured in the storage solution. Collagen degradation was higher in PA- and EDTA-demineralized dentin. Chlorhexidine digluconate reduced collagen degradation in these groups only for 24 h. When dentin was demineralized with Clearfil SE Bond or Xeno V, collagen degradation was reduced by up to 30%, but the addition of exogenous MMP-2 significantly increased collagen degradation. In self-etchant-treated dentin, the inhibitory effect of CHX on MMPs lasted for up to 3 wk. Treating dentin with EDTA, PA or self-etching agents produces enough demineralization to permit cleavage of the exposed collagen. Monomer infiltration may exert protection on demineralized collagen, probably through immobilization of MMPs. The partial inhibitory action of CHX on MMP activity produced by self-etching adhesives was prolonged compared with the short-acting PA- or EDTA-treated dentin.

Isolamento do Campo Operatório: Panorama de Utilização em Consultórios e Clínicas Privadas de Belo Horizonte, MG, Brasil / Rubber Dam: Use in Private Clinics in Belo Horizonte, MG, Brazil

Objetivo: verificar a utilização de isolamento em consultórios e clínicas privadas em Belo Horizonte, observando-se: tipo, procedimentos executados com isolamento e o motivo da escolha; além de fatores como: tempo de formação dos cirurgiões-dentistas (CDs), classe econômica dos pacientes e presença de pessoal auxiliar (ASB). Método: a amostra elegível foi formada por CDs atuantes na região Centro-Sul da cidade. A amostra final de conveniência foi de 115 CDs que responderam a um instrumento de coleta de dados com questões descritivas e objetivas. Os dados foram analisados descritivamente e pelo teste Qui-quadrado (p≤0,05).Resultados: dos CDs que participaram da pesquisa, 55% eram do gênero feminino; 63,5% tinham entre 23 e 35 anos; 39% tinham menos de cinco anos de atividade profissional e 59% eram especialistas. Eram da região Central 69% e Sul 31%; têm ASB 66% dos CDs. Os pacientes foram classificados em classe econômica A (11%), B (30%), C (34%), D (16%) e E (9%). Relataram utilizar algum tipo de isolamento 82% dos CDs (36% relativo; 28% absoluto; e 36% ambos). O grau de aceitação dos pacientes quanto aos métodos de controle de umidade foi considerado alto para 52% dos CDs. O principal motivo para escolha doisolamento absoluto foi o controle de infecção (27%) e para o relativo foi a praticidade (24%). O isolamento absoluto é utilizado principalmente na endodontia (38%) e o relativo em restaurações (33%). Gênero (p=0,6483), tempo de atividade (p=0,2576), especialidade (p=0,0733) e presença de ASB (p=0,4127), não influenciaram significativamente na escolha do tipo de isolamento. Conclusão: a maioria dos CDs relatou utilizar algum tipo de isolamento do campo operatório e aponta como principais vantagens a biossegurança, a praticidade e melhor qualidade dos procedimentos executados

Objective: The aim of this study was to investigate the use of isolation in offices and private clinics in Belo Horizonte, it was observed: the type, procedures performed in isolation and the reason for their choices. In addition to those factors were also observed the duration of the dentistsÆ training, the patientsÆ economic class and the presence of an office assistant.Method: The eligible sample consisted of active dentist in the southcenter region of the town. The final sample of convenience was 115 professionals who answered to an instrument data collection with descriptive and objective questions. The results were analyzed descriptively and by Qui-Square test (p≤0,05).Results: Among the dentist in the survey 55% were female, 63.5% were between 23 and 35 years old, 39% had less than five years of professional activity and 59% were specialists; 69% were from the central region and 31% from the south; 66% of the dentists have assistant in office. Patients were classified according to their economic class; class A (11%), B (30%), C (34%), D (16%) and E (9%). 82% of the dentists reported the use of some type of insulation, (36% relative, 28% absolute, and 36% both). The degree of the patientsÆ acceptance to methods of moisture control was considered high, for 52% of the professionals. The main reason for choosing the absolute isolation was the control of infection (27%) and the relative was the practicality (24%). The rubber dam is mainly used in endodontics (38%) and the relative isolation is used in restorations (33%). The gender (p=0.6483), professional activity time (p=0.2576), training (p=0.0733) and presence of an office assistant (p=0.4127) havenÆt significant influence in the type of isolation choice. Conclusion: The most of dentists reported using some type of isolation of the operative field and indicated that the main advantages are the biosafety, practicality and quality of procedures performed

Effect of pulse duration of Er: YAG laser on dentin ablation.

The present study examined the effects on dentin ablation efficiency arising from various pulse durations of Er: YAG laser at a fixed energy fluence. Ten flat human dentin disks were prepared and exposed to an Er: YAG laser at 1 pps for three seconds at pulse durations of 100-500 microsec with 150 mJ/pulse (40.0 J/cm x pulse). The depth and diameter of the ablated dentin were measured and the ablation volume was estimated. Irradiated surfaces and cross-sections were observed using a SEM. Depth of the removed dentin increased and the diameter of the spot decreased without a change in the estimated volume at increased pulse durations. SEM observation of the irradiated surfaces revealed that there were no morphological differences when the pulse duration was changed. When the specimens were cross-sectioned, the ablated dentin had a dome shape and there was a dark layer under the irradiated surface.