Influence of intrapulpal pressure simulation on the bond strength of adhesive systems to dentin

The purpose of this study was to evaluate the influence of intrapulpal pressure simulation on the bonding effectiveness of etch & rinse and self-etch adhesives to dentin. Eighty sound human molars were distributed into eight groups, according to the permeability level of each sample, measured by an apparatus to assess hydraulic conductance (Lp). Thus, a similar mean permeability was achieved in each group. Three etch & rinse adhesives (Prime & Bond NT - PB, Single Bond -SB, and Excite - EX) and one self-etch system (Clearfil SE Bond - SE) were employed, varying the presence or absence of an intrapulpal pressure (IPP) simulation of 15 cmH2O. After adhesive and restorative procedures were carried out, the samples were stored in distilled water for 24 hours at 37°C, and taken for tensile bond strength (TBS) testing. Fracture analysis was performed using a light microscope at 40 X magnification. The data, obtained in MPa, were then submitted to the Kruskal-Wallis test ( a = 0.05). The results revealed that the TBS of SB and EX was significantly reduced under IPP simulation, differing from the TBS of PB and SE. Moreover, SE obtained the highest bond strength values in the presence of IPP. It could be concluded that IPP simulation can influence the bond strength of certain adhesive systems to dentin and should be considered when in vitro studies are conducted

Avaliação da intensidade de contaminação de pontas de seringa tríplice

Effective infection control procedures to prevent cross-contamination in the dental office include care with air/water syringes. The authors had the purpose to verify the bacterial contamination of air/water syringes used in patients seen at the Restorative Dental Clinic, School of Dentistry, University of São Paulo, Brazil. Fifty disposable tips (Riskcontrol, Injecta Prod. Odontológicos) were analysed: 10, immediately after the package was opened; 10, after a single use followed by disinfection with 70% alcohol for one minute; 30, after a single use without any posterior disinfection. The samples were transported to the laboratory and, under aseptic condition, rolled and compressed on a Tryptic Soy Agar surface with 5% of defibrillated sheep blood. After a 96-hour incubation, the reading was carried out with the help of a lens. According to the manufacture’s information, the disposable tips were sterilized. In all of the tips used in patients, an uncountable amount of cfu (colony formation units) was found, revealing great contamination. In the disposable tips disinfected after being used, there was small bacterial growth, but that was incompatible with cross-contamination prevention. Therefore, we conclude that disposable air/water syringes tips must have a single use.O controle de infecção cruzada em consultórios odontológicos inclui cuidados especiais com as seringas tríplices. Os autores pesquisaram a intensidade de contaminação pela microbiota bucal, de pontas de seringas tríplices usadas no atendimento a pacientes de Dentística Restauradora. Cinqüenta pontas descartáveis (Riskcontrol, Injecta Prod. Odontológicos) foram avaliadas: 10, imediatamente após a abertura da embalagem; 30, após o uso em pacientes; e 10, após o uso e a desinfecção com álcool etílico 70% P/V, friccionado por um minuto. Em câmara de fluxo laminar, as pontas foram "roladas" sobre a superfície de Tryptic Soy Agar, suplementado com 5% de sangue desfibrinado de carneiro. Após 96 horas de incubação anaeróbia, foi feita a avaliação da quantidade de unidades formadoras de colônias (ufc) desenvolvidas. Confirmando a informação do fabricante, as pontas estavam estéreis quando retiradas da embalagem. Em todas as pontas usadas em pacientes, observou-se um número incontável de ufc (maior que 300), revelando intensa contaminação. Nas pontas usadas e desinfetadas com álcool etílico 70% P/V, verificou-se apreciável redução na contagem de colônias (1 a 100 ufc), mas incompatível com a segurança biológica. Os resultados sugerem, como condição ideal, o uso de pontas descartáveis nas seringas tríplices

Bone Tissue Response to Porous and Functionalized Titanium and Silica Based Coatings

Background: Topography and presence of bio-mimetic coatings are known to improve osseointegration. The objective of this study was to evaluate the bone regeneration potential of porous and osteogenic coatings. Methodology: Six-implants [Control (CTR); porous titanium coatings (T1, T2); thickened titanium (Ti) dioxide layer (TiO2); Amorphous Microporous Silica (AMS) and Bio-active Glass (BAG)] were implanted randomly in tibiae of 20-New Zealand white rabbits. The animals were sacrificed after 2 or 4 weeks. The samples were analyzed histologically and histomorphometrically. In the initial bone-free areas (bone regeneration areas (BRAs)), the bone area fraction (BAF) was evaluated in the whole cavity (500 mm, BAF-500), in the implant vicinity (100 mm, BAF-100) and further away (100–500 mm, BAF-400) from the implant. Bone-to-implant contact (BIC-BAA) was measured in the areas where the implants were installed in contact to the host bone (bone adaptation areas (BAAs)) to understand and compare the bone adaptation. Mixed models were used for statistical analysis. Principal Findings: After 2 weeks, the differences in BAF-500 for different surfaces were not significant (p.0.05). After 4 weeks, a higher BAF-500 was observed for BAG than CTR. BAF-100 for AMS was higher than BAG and BAF-400 for BAG was higher than CTR and AMS. For T1 and AMS, the bone regeneration was faster in the 100-mm compared to the 400-mm zone. BIC-BAA for AMS and BAG was lower after 4 than 2 weeks. After 4 weeks, BIC-BAA for BAG was lower than AMS and CTR. Conclusions: BAG is highly osteogenic at a distance from the implant. The porous titanium coatings didn’t stimulate bone regeneration but allowed bone growth into the pores. Although AMS didn’t stimulate higher bone response, it has a potential of faster bone growth in the vicinity compared to further away from the surface. BIC-BAA data were inconclusive to understand the bone adaptation.status: publishe

Study of the influence of alternative tools and techniques of cavity preparation on teh bond strength of adhesive system to dentin

A atual tendência ao desenvolvimento de uma odontologia minimamente invasiva tem sido responsável pela introdução de instrumentos e técnicas alternativas de preparo cavitário. Porém, tais tecnologias deveriam não somente preencher os requisitos de uma odontologia conservadora, mas também preparar as paredes da cavidade para o tratamento restaurador adesivo subseqüente. Assim, o objetivo deste estudo foi testar a hipótese nula de que: 1) tanto técnicas convencionais quanto técnicas alternativas de preparo cavitário são capazes de produzir um substrato dentinário receptivo à adesão de sistemas autocondicionantes; e 2) A efetividade adesiva de sistemas autocondicionantes não é influenciada pela interposição da camada de esfregaço. Cem molares humanos íntegros foram aleatoriamente divididos em 20 grupos de acordo com o adesivo e a técnica ou instrumento utilizado. Superfícies planas de dentina média oclusal foram preparadas com instrumento rotatório diamantado convencional (IR); fratura; instrumento rotatório CVD (IRCVD); instrumento ultra-sônico CVD (IUCVD); e laser de Er,Cr:YSGG .Um adesivo condicione-e-lave (Optibond FL/OB) e três autocondicionantes (Adper Prompt L-Pop/AP, Clearfil SE Bond/SE e Clearfil S3 Bond/S3) foram empregados. Os espécimes foram construídos com o compósito Z100/3M ESPE. A resist6encia adesiva foi determinada por meio de teste de microtração após 24 h de estocagem em água a 37oC. Amostras adicionais foram processadas para análise em MEV quanto às características morfológicas apresentas após o preparo das superfícies dentinárias em cada caso. O teste de Kruskal-Wallis (p<0,05) determinou que os grupos preparados com IRCVD, IUCVD e laser apresentaram menores valores de resistência adesiva quando comparados aos grupos controle (IR e fratura). Além disso, os adesivos de menor acidez (SE e S3) foram mais eficientes quando aplicados em dentina fraturada. Concluiu-se que o uso de instrumentos e técnicas alternativas de preparo cavitário comprometeu a adesão à dentina e que a camada de esfregaço influencia de forma negativa a adesão de sistemas autocondicionantes suaves.The current trend toward minimal invasive dentistry has introduced alternative cavity preparation techniques. However, these technologies should not only fulfill the requirements of a conservative philosophy, but also prepare the cavity walls for the subsequent bonding restoration. The purpose of this study was to assess the null hypotheses that: (1) both conventional and alternative cavity preparation techniques are equally receptive to adhesion; and (2) bonding effectiveness of mild adhesives is not influenced by smear layer (SL) interposition. Eighty sound human molars were divided into 20 groups according to adhesive and cavity preparation technique. Flat mid-occlusal dentin surfaces were prepared with regular diamond bur (DB), scalpel blade (SB), CVDentus bur in high speed turbine (CB), CVDentus tip in ultrasound (CT), and Er,Cr:YSGG laser (L). One etch-and-rinse (Optibond FL (OB)) and three self-etch systems (Adper Prompt L-Pop (AP), Clearfil SE Bond (SE) and Clearfil S3 Bond (3S)) were employed. Specimens were built up with Z100/3M ESPE composite. The microtensile bond strength was determined after 24h of storage in water at 37oC. Additional samples were processed for SEM analysis on morphological aspects in each situation. Kruskal-Wallis test (p<0,05) determined that groups prepared with CB, CT and L presented lower ?TBS values than the control groups (DB and SB), and that adhesives with lower acidity (SE and 3S) were more effective when applied on fractured surfaces (SB). It was concluded that the use of alternative techniques for cavity preparation caused damages to dentin surface, compromising the adhesion to this substrate. Moreover, the bonding effectiveness of mild adhesives was improved by SL absence

Phosphorylated Pullulan Coating Enhances Titanium Implant Osseointegration In A Pig Model

To investigate the effect of coating a titanium implant surface with a phosphorylated exopolysaccharide, pullulan, on the peri-implant bone formation and implant osseointegration. Materials and Methods: Implants were placed in the skull bone of 12 domestic pigs and healed for 1 or 3 months. Osseointegration of (un)coated implants was evaluated by quantitative histology (peri-implant bone fraction [BF] and bone-to-implant-contact [BIC]). The Wilcoxon-Mann-Whitney test with alpha = .05 was used to statistically compare BF and BIC of the coated and uncoated implants. Results: Significantly more BF was observed surrounding pullulan-coated implants compared with uncoated implants (P < .05) and for both healing periods (P < .05). BIC was positively affected by the exopolysaccharide coating, with significantly more BIC after the 3-month healing period compared with the uncoated implant (P < .05). Furthermore, BIC remained stable over time for the coated implants, while it significantly decreased for the uncoated ones (P < .05). Conclusion: These findings reveal the capacity of functionalizing the titanium implant surface with phosphorylated pullulan to improve the mineralization of the implant-bone interface.322282290GC Inc. (Tokyo, Japan

Bond durability of self-adhesive composite cements to dentine

Clinically, the most easy-to-use composite cements are the so-called self-adhesive composite cements (SAC's). Hardly any data is however today available on the long-term bonding effectiveness of such luting composites. The purpose of this study was to evaluate the bond durability of different composite cements used to lute feldspathic ceramic blocks onto dentine.publisher: Elsevier articletitle: Bond durability of self-adhesive composite cements to dentine journaltitle: Journal of Dentistry articlelink: http://dx.doi.org/10.1016/j.jdent.2013.07.008 content_type: article copyright: Copyright © 2013 Elsevier Ltd. All rights reserved.status: publishe

Bone tissue response to BMP-2 adsorbed on amorphous microporous silica implants

Aim To evaluate bone regeneration potential of bone morphogenetic protein-2 (BMP-2) adsorbed on amorphous microporous silica (AMS). Materials & Methods Four implants [titanium as control (CTR); AMS-coated titanium (AMS), BMP-2 adsorbed on titanium (CTR+BMP) and AMS (AMS+BMP)] were implanted randomly in the tibiae of 20 New Zealand white rabbits. Bone specimens with implants were retrieved 2/4 weeks post implantation and analysed histologically and histomorphometrically. Bone fraction was measured in initial bone-free area (bone regeneration area, BRA) and in the area with initial bone–implant contact [bone adaptation area (BAA)] (BFBRA & BFBAA). Bone–implant contact was measured in BRA (BICBRA). In vitro BMP-2 release profiles were determined to evaluate the impact of the carrier surface. Mixed models were used for statistical analysis. Results BMP-2 release profiles were different for CTR+BMP and AMS+BMP. BICBRA and BFBRA were significantly increased after 4 weeks compared to 2 weeks for AMS, CTR+BMP and AMS+BMP. However, no differences between the implant types were observed within both healing periods. BFBAA for CTR+BMP was smaller than that for CTR and AMS+BMP after 4 weeks. Despite slower BMP-2 release, AMS+BMP did not stimulate bone regeneration. CTR+BMP caused bone resorption at the bone–implant interface. Conclusions BMP-2 functionalized implant surfaces failed to stimulate bone regeneration and osseointegration.status: publishe

Bone tissue response to implant surfaces functionalized with phosphate-containing polymers

OBJECTIVES: Inorganic polyphosphates are said to stimulate the activity of osteoblast-like cells in vitro. The purpose of this study was to evaluate in vivo bone regeneration around implants treated with polyphosphoric acid (PPA) and phosphorylated pullulan (PPL). MATERIAL AND METHODS: Two types of implants with different surface roughness (R1: Sa ≈ 0.23 μm; R2: Sa ≈ 1.35 μm) were treated with three solutions (distilled water, 10%wt PPA, or 10%wt PPL) prior to implantation in both tibia of twelve female white rabbits. Each animal received six implants randomly positioned according to their surface roughness and treatment: R1 + water; R1 + PPA; R1 + PPL; R2 + water; R2 + PPA; R2 + PPL. Animals were sacrificed after 1 or 4 weeks, and samples were prepared for histological and histomorphometrical analysis. Bone regeneration areas were evaluated for bone-to-implant contact (BIC) and bone fraction (BF) in areas 100 and 500 μm remote from the implant surface. Data were statistically analyzed by means of Friedman and Wilcoxon matched-pair tests (P  0.05). Surface roughness influenced neither BIC nor BF. CONCLUSIONS: Implant surface treatment with phosphate-containing polymers may positively influence osseointegration.status: publishe

Current concepts and techniques for caries excavation and adhesion to residual dentin

The advent of "Adhesive Dentistry" has simplified the guidelines for cavity preparation enormously. The design and extent of the current preparations are basically defined by the extent and shape of the caries lesion, potentially slightly extended by bevelling the cavity margins in order to meet the modern concept of minimally invasive dentistry. New caries excavation techniques have been introduced, such as the use of plastic and ceramic burs, improved caries-disclosing dyes, enzymatic caries-dissolving agents, caries-selective sono/air abrasion and laser ablation. They all aim to remove or help remove caries-infected tissue as selectively as possible, while being minimally invasive through maximum preservation of caries-affected tissue. Each technique entails a specific caries-removal endpoint and produces residual dentin substrates of different natures and thus different receptiveness for adhesive procedures. This paper reviews the newest developments in caries excavation techniques and their effect on the remaining dentin tissue with regard to its bonding receptiveness.status: publishe

Effect of insertion torque on titanium implant osseointegration: an animal experimental study

Objective To evaluate the effect of implant insertion torque on the peri-implant bone healing and implant osseointegration. Material and methods Bilaterally in the tibia of five adult New Zealand white rabbits, 20 implants were installed, subdivided into four groups, corresponding to two insertion torque conditions (low, 50 Ncm) and 2 experimental periods (2 weeks vs. 4 weeks of healing). The implant insertion torque was determined by the surgical drill diameter relative to the implant diameter. Implant osseointegration was evaluated by quantitative histology (bone-to-implant contact with host bone [BIC-host], with neoformed bone [BIC-de novo], with both bone types [BIC-total], and peri-implant bone [BA/TA]). Every response was modelled over time using GEE (general estimation equation) with an unstructured varianceâ covariance matrix to correct for dependency between the measurements from one animal. The statistical significance level of α = 0.05 was applied. Results Significantly, more BIC-host and BIC-total were recorded for H implants compared with L implants after 2 week of healing (P = 0.010 and P = 0.0001, respectively). However, this result was no longer found for the extended healing period. Furthermore, BIC-total significantly increased over time for L implants (P < 0.00001). In contrast, the significant increase in BA/TA over time was found for H implants (P < 0.01). Finally, H insertion torque led to an increased BA/TA after 4 week of healing (P < 0.02) compared with the L insertion protocol. Conclusion L insertion torque implants installed in the rabbit tibial bone osseointegrate with considerable de novo bone formation. This bone neoformation enables L implants to catch up, already during the early osseointegration stage, the initial inferior amount BIC contact compared with that of H implants. A negative impact of the created strain environment accompanying H insertion torque implant installation on the biological process of osseointegration could not be observed, at least not at tissue level.status: publishe