Influence of soft tissue grafting, orofacial implant position, and angulation on facial hard and soft tissue thickness at immediately inserted and provisionalized implants in the anterior maxilla.

BACKGROUND: Resorption of hard and soft tissues following immediate implant insertion is frequently reported. Data regarding the influencing factors on facial tissue thickness are rare. PURPOSE: This retrospective study investigated the impact of connective tissue grafting, the orofacial angulation and position of immediately inserted and provisionalized implants on the facial hard and soft tissue thickness in the anterior maxilla within a 1- to 5-year follow-up. MATERIAL AND METHODS: Implants with the prerequisite of having preoperative and postoperative cone beam computed tomography (CBCT) and a follow-up of 1 to 5 years were included. Facial bone deficiencies were grafted flaplessly with autogenous bone in all sites. In a subgroup of implants additional connective tissue grafting was performed, whereas the remaining implants were not grafted with soft tissue. The orofacial tooth and implant angulation, the change of horizontal position and the facial bone thickness were measured by CBCT, the facial mucosa thickness by an ultrasonic device. RESULTS: In total, 76 implants were placed in 55 patients. Sixty-nine sites showed a facial bone defect. Thirty-eight received a connective tissue graft additionally. All implants were still in function after a mean follow-up of 36 months. The mean thickness of the facial mucosa was 1.72 mm at 1 mm, 1.63 mm at 4 mm, 1.52 mm at 6 mm, and 1.66 mm at 9 mm apically to mucosal margin. The bone thickness was 0.02, 0.25, and 0.36 mm initially and 1.32, 1.26, and 1.11 mm finally at 1, 3, and 6 mm apically to implant shoulder level. Mixed model analysis revealed an impact of the preoperative bone status on the facial bone increase. The facial soft tissue thickness was significantly influenced by the gingival biotype. CONCLUSIONS: The results indicate that an initial severe hard tissue defect allows for significant bone regeneration. The facial soft tissue thickness is primarily influenced by the gingival biotype.

Interim therapeutic restoration approach versus treatment under general anaesthesia approach.

BACKGROUND: Although dental treatment under general anaesthesia (GA) remains the long-established approach for treating anxious children, treatment under GA presents with increased risks, costs and parental acceptability issues. Interim therapeutic restoration (ITR) has been proposed as an alternative approach. AIM: To compare the incidence and types of failures between children managed with the ITR approach and those managed under GA within 12 months of treatment completion. DESIGN: A retrospective cohort study of children who received dental treatment utilizing the ITR approach was compared to children treated under GA. Age, gender and dental disease matching was done. Statistical analyses were carried out with Independent t-test and chi-square analyses. RESULTS: A total of 132 children (GA = 66, ITR = 66) were included, and the groups did not differ in terms of initial age, sex, dmft and initial behaviour score. ITR group had a significantly higher rate (P < 0.001; 95% CI: [0.21 to 0.97]) of restorative failure and visits required when compared to the GA group. There were no difference for incidence of pain (P = 0.55; 95% CI: [-0.074 to 0.10]) and behaviour scores (P = 0.46) between the two groups at the 12-month visit. CONCLUSIONS: ITR approach may be a viable alternative to the GA approach when treating paediatric dental patients.

Neuropsychological Effects of Mercury Exposure Among Dentists in Monastir City.

AIMS: The aim of this study is to assess the neuropsychological manifestations of mercury exposure in dentists. METHODS: A cross-sectional study was carried out including 64 dentists matched to a control group according to age and gender. This study protocol included a neurological evaluation, a questionnaire assessing the study groups' general characteristics and personal factors that may affect mercury urinary excretion in both groups. EUROQUEST questionnaire and Hospital Anxiety and Depression scale (HADS) were used to evaluate the neuropsychological symptoms reported during the last 12 months. In both groups, mercury impregnation was assessed by monitoring urinary mercury. RESULTS: In the exposed group, scores of neurological symptoms, memory disturbances and anxiety were found to be significantly higher than those in controls (p < 0.01). Mean scores of HAD Depression's scale were higher in the exposed group than in controls. Most of the neurotoxic manifestations were correlated to the levels of urinary mercury excretion in the exposed group. Mean levels of urinary mercury were significantly higher in the dentists group than in controls, with respective values of 21.1 ± 19.6 µg/g of creatinine and 0.05 ± 0.9 µg/g of creatinine. In nine dentists having urinary mercury levels higher than 35 µg/g of creatinine, neurological examination showed a bilateral and symmetric intentional tremor in both upper limbs. In the exposed group, the neuropsychological manifestations and levels of urinary mercury were found to be significantly correlated. CONCLUSION: Increased levels of urinary mercury observed in dentists suggest that exposure to mercury vapour emissions adversely affects dental professionals, therefore prevention measures should be strengthened, with a special medical supervision program of dentists exposed to mercury vapours should be implemented. We have also outlined some relevant patents in this article.

Use of Oral Chroma™ in the assessment of volatile sulfur compounds in patients with fixed protheses.

Prosthetic rehabilitation improves the patient's quality of life and oral health. The purpose of the present study was to assess the production of volatile sulfur compounds (VSCs) using Oral Chroma™ in patients wearing provisional and permanent fixed prosthesis, who were treated or not, with supportive non-surgical periodontal therapy. A total of 10 healthy patients not affected by periodontal disease and who needed the restoration of at least two edentulous single sites were included in the present study. Registrations of VSCs were carried out with a Gas Chromatograph OralChroma™ (Oral Chroma™, Abimedical, Abilit Corp., Osaka, Japan) one month after placement of the provisional restoration (group 1) and one month after placement of the final restoration (group 3). After each measurement, professional oral hygiene was carried out both on patients with provisional (group 2) and permanent prostheses (group 4) and VSC values were registered. The results showed that there were no statistical significant differences in the VSC quantity between groups with temporary or permanent prostheses. Meanwhile, statistically significant differences were found in VCS values between groups before and after the professional health care session (p less than 0.05). Also it was observed that dimethyl sulphide (CH3)2S was present in all the study groups. The present preliminary study suggests that OralChroma™ produce a comprehensive assessment of VSC in the clinical diagnosis of halitosis and that professional oral hygiene seems to influence VSC production. However, further clinical long-term studies with a larger sample size are necessary for a better understanding of halitosis manifestation in patients wearing provisional and permanent fixed prosthesis.

Coronal microleakage of 3 temporary filling materials used for endodontic treatment: an in vitro study.

Most root canal treatments are performed over multiple appointments. The temporary sealing material used between sessions must have sealing properties capable of preventing microleakage. This study assessed the degree of microleakage of temporary sealing materials according to time spent blocking the access cavity. Endodontic treatments with a standardized protocol were performed on 63 healthy, single-rooted, caries-free human teeth. The teeth were divided randomly into 5 groups. Groups 1-3 were each treated with 1 of 3 sealing materials, while Group 4 and 5 served as positive and negative controls, respectively. Data was obtained and analyzed with nonparametric tests (Kruskal-Wallis and Chi-square). Results indicated statistically significant differences between materials and the degree of microleakage (P = 0.000). All 3 sealing materials allowed microleakage within 48 hours, with glass ionomer cement demonstrating the most microleakage.

Periodontopathogens around the surface of mini-implants removed from orthodontic patients.

OBJECTIVE: To verify if mini-implant mobility is affected by the presence of periodontopathogens, frequently associated with peri-implantitis. MATERIALS AND METHODS: The surfaces of 31 mini-implants used for skeletal anchorage in orthodontic patients were evaluated. Polymerase chain reaction was used for identification of the presence of DNA from three different periodontopathogens ( P. intermedia [ Pi ], A. actinomycetemcomitans [ Aa ], and P. gingivalis [ Pg ]) in 16 mini-implants without mobility (control group) and 15 mini-implants with mobility (experimental group). RESULTS: The results showed that Pi was present in 100% of the samples, from both groups: Aa was found in 31.3% of the control group and in 13.3% of the experimental group. Pg was detected in 37.4% of the control group and in 33.3% of the experimental group. The Fisher exact test and the odds ratio (OR) values for Aa and Pg (OR  =  0.34; 95% confidence interval [CI]: 0.05-2.10 and OR  =  0.61; 95% CI: 0.13-2.79, respectively) showed no significant association (P > .05) between the periodontopathogens studied and the mobility of the mini-implants. CONCLUSIONS: It can be concluded that the presence of Aa , Pi , and Pg around mini-implants is not associated with mobility.

A retrospective study of the risk factors for ridge expansion with self-tapping osteotomes in dental implant surgery.

PURPOSE: To analyze the risk factors associated with the survival of self-threading implants placed with the ridge expansion technique using self-tapping osteotomes after at least 24 months. MATERIALS AND METHODS: This retrospective study followed patients for at least 2 years in whom implants had been inserted by means of the ridge expansion technique. The patient was taken as the unit of analysis, and the loss of any implant as a result of mobility at any time during the follow-up period was considered as a failure. A number of patient variables were recorded: sociodemographic (age/sex), anatomical (bone quantity/quality, expansion zone), infection history (prior antibiotic therapy for active infection), prosthodontic (type of provisional prosthesis and type of definitive rehabilitation), and surgical (number of surgical stages, the use of biomaterials or atraumatic maxillary sinus elevation). Risk factors were expressed as values of relative risk (RR) and the odds ratio. RESULTS: Seventy-four patients (157 implants) were followed over a mean period of 38.8 ± 7.7 months. Most patients (91.9%) did not lose any implants, and failures occurred mainly after implant loading (5.4%). Sociodemographic factors (sex and age) were not associated with a significant risk of implant failure. However, the existence of previous local infection (RR = 34.0), the use of an immediate fixed provisional prosthesis (RR = 15.0), and type D3 bone (RR = 5.1) were seen to be the main risk factors involved in this technique for the period assessed. CONCLUSIONS: The risk of failure when implants are placed using self-tapping osteotomes was highest in patients who had active local infection; immediate provisionalization and less dense bone were also associated with additional risk of failure.

Adverse events on the use of interim therapeutic in schoolchildren: silver diamine fluoride × interim therapeutic restorative - a pilot study / Efeitos adversos de técnicas provisórias em crianças: diamino fluoreto de prata x tratamento restaurador provisório - um estudo piloto

PURPOSE: Silver diamine fluoride (SDF) is a caries prevention and arresting agent that is easy to apply clinically. Interim therapeutic restorations (IRT) are also known to be a simple and effective method for treating caries in children. This study examines whether treatment with 30% silver diamine fluoride (SDF) will cause fewer adverse events than the available interim therapeutic restorations in underprivileged schoolchildren with cavities. METHODS: We conducted a three-month pilot study comparing the adverse effects of IRT using glass ionomer cement (Fuji IX, GC America, Inc.) with those of 30% silver diamine fluoride (Cariostop Biodynamic®, Brazil) in 50 children aged 6 years. RESULTS: In the SDF group, all caries were arrested and no pain, abscess or fistula was reported. Of the children assigned to the Fuji IX group, 24% reported toothache (P < 0.05). There was no significant difference in the occurrence of fistula and abscess in the two groups. CONCLUSION: The authors suggest that for underprivileged schoolchildren with caries, the use of SDF when an appropriate clinical setting is not available resulted in fewer adverse effects than did treatment with an interim therapeutic restorative using FUJI IX.

OBJETIVO: O Diamino fluoreto de prata, uma solução de fácil aplicação e que não precisa de um ambiente clínico para o seu uso, é um agente de notável capacidade de paralisar e prevenir cárie. Outro método simples e eficaz para o tratamento da cárie em crianças são Restaurações provisórias. Este estudo examinou o surgimento de efeitos adversos em escolares tratadas com Diamino fluoreto de prata (DFP) comparado com aquelas tratadas com o Tratamento Restaurador Provisório. METODOLOGIA: Foi realizado um estudo piloto de três meses comparando os efeitos adversos das restaurações provisórias, utilizando cimento de ionômero de vidro Fuji IX (GC America, Inc.), com o Diamino fluoreto de prata a 30% (Cariostop Biodinâmica®, Brasil), em 50 crianças com 6 anos de idade. RESULTADOS: O grupo DFP teve todas as suas cáries paralisadas e não apresentou dor, abscesso ou fístula. Das crianças tratadas com Fuji IX, 24% delas relataram dor de dente (P < 0,05). Para fístula e abscesso, não foi verificado diferença estatisticamente significativa. CONCLUSÃO: Os autores sugerem que, para crianças portadoras de cárie, sem acesso aos serviços de saúde, o DFP apresentou menos efeitos adversos do que o tratamento restaurador provisório utilizando FUJI IX.

Chairside vs. labside ceramic inlays: effect of temporary restoration and adhesive luting on enamel cracks and marginal integrity.

OBJECTIVES: To assess the influence of different temporary restorations and luting techniques of labside and chairside ceramic inlays on enamel defects and marginal integrity. METHODS: 120 extracted human third molars received MOD preparations with one proximal box each limited in either enamel or dentin. 64 Cerec 2 inlays and 56 IPS Empress I inlays were randomly assigned to the following groups (fabrication mode: chairside (CS)=no temporary restoration (TR), labside (LS)=TR with Luxatemp (L) inserted with TempBond NE, or Systemp.inlay (SI) without temporary cement), luting technique: SV=Syntac/Variolink II, RX=RelyX Unicem: A: Cerec inlays were luted with (1) CS/SV. (2) CS/SV/Heliobond separately light-cured. (3) CS/RX. (4) LS/L/SV. (5) LS/L/RX. (6) LS/SI/SV. (7) LS/SI/RX. (8) LS/SI/RX with selective enamel etching. B: Empress. (9) L/SV. (10) L/SV/Heliobond separately light-cured. (11) L/RX. (12) SI/SV. (13) SI/SV, Heliobond separately lightcured. (14) SI/RX. (15) SI/RX after selective enamel etching. Before and after thermomechanical loading (TML: loading time of TR 1000×50N+25 thermocycles (TC) between +5°C and +55°C; clinical simulation: 100,000×50N+2500 TC) luting gaps, enamel cracks, and marginal adaptation to enamel and dentin were determined under an SEM microscope (200×) using replicas. RESULTS: Loading time of temporary restorations negatively affected enamel integrity and enamel chipping (p<0.05). Luxatemp resulted in less enamel cracks than Systemp.inlay (p<0.05). Syntac/Variolink achieved better marginal enamel quality than RelyX Unicem in all groups (p<0.05). Marginal quality in dentin revealed no differences when no temporary cement was used (p>0.05). Temporary cement negatively affected dentin margins when RelyX Unicem was used (p<0.05). SIGNIFICANCE: Chairside-fabricated Cerec inlays reduce the risk of enamel cracks and marginal enamel chipping due to omitted temporary restorations. Syntac/Variolink revealed a significantly better performance than RelyX Unicem.

Sensory transduction in human teeth with inflamed pulps.

The effects of pulpal inflammation on the sensitivity of dentin to cold (5°C) and negative hydrostatic pressure (-300 mm Hg) stimuli in man were compared, since recent evidence suggests that these stimuli excite different classes of sensory receptors. Dentin was exposed in premolars in 14 participants aged 15-25 years. Stimuli were applied to etched dentin immediately after cavity preparation and after the cavity had been filled with gutta percha for 7 days. This treatment increased significantly the intensity of pain produced by cold, and at the same time decreased that evoked by negative pressure stimuli. Pulpal blood flow was increased in the treated teeth, indicating that their pulps were inflamed. It is concluded that the sensory receptors responsible for the response to cold were probably sensitive to some change other than an outward flow of fluid in dentinal tubules, which would be caused by both forms of stimulus.

Endosseous implant failure influenced by crown cementation: a clinical case report.

Implant dentistry has developed predictable treatment outcomes. Nevertheless, there are multiple reasons for implant failure. This case report documents a previously unreported type of implant failure that occurred 1 month after crown cementation. The implant failure is believed to be associated with retained excess subgingival cement.

Effects of provisional acrylic resins on gingival fibroblast cytokine/growth factor expression.

STATEMENT OF PROBLEM: Several studies have reported that polymerized resin materials may release agents into surrounding tissues. These agents could alter cytokine/growth factor expression. PURPOSE: The purpose of this study was to determine the effects that provisional acrylic resins have on cell toxicity and the expression of cytokines/growth factors from human gingival fibroblasts (HGFs). MATERIAL AND METHODS: The materials used in this study were chemically activated bis-acryl composite (Chem-Bis), chemically activated polyethyl methacrylate (Chem-PEMA), chemically activated polymethyl methacrylate (Chem-PMMA), and heat-activated polymethyl methacrylate (Heat-PMMA) resins. HGFs were incubated for 72 hours in the presence of eluate from each resin and in the absence of any eluate (negative control). The conditioned media were then collected and stored at -70 degrees C. Cell toxicity was determined using a lactate dehydrogenase method. Cytokine/growth factor expression was examined using cytokine antibody arrays. The experiments were repeated 3 times. The data were analyzed with 1-way ANOVA, Mann-Whitney test, and 1-sample t test (alpha=.05). RESULTS: There was no significant cell toxicity observed from the eluates. The cytokine/growth factor expression induced by Chem-Bis was significantly greater than the control for growth-regulated oncogene (GRO) (P<.001), monocyte chemoattractant protein-1 (MCP-1) (P=.031), and tumor necrosis factor-beta (TNF)-beta (P=.009). For Chem-PEMA, the cytokine/growth factor expression was significantly greater than the control for GRO-alpha (P=.022), interleukin (IL)-13 (P=.031), and TNF-alpha (P=.017). The cytokines/growth factors induced by Chem-PEMA were significantly less than the control (P=.008) and Chem-Bis for IL-8 (P=.042). The expression induced by Chem-PMMA was significantly greater than the control for IL-13 (P=.036), IL-1 alpha (P=.003), IL-2 (P=.020), and IL-5 (P=.045). Finally, Heat-PMMA induced significantly greater levels than the control for GRO (P<.001) and IL-13 (P=.008). CONCLUSIONS: This study demonstrated that the resins evaluated were nontoxic to the HGFs. There were changes in the cytokine/growth factor levels that were statistically significant, but may not be clinically significant.

Microbial microleakage in temporary restorative materials after post space preparation / Infiltração microbiana em materiais restauradores temporários após preparo para retentores intrarradiculares

Purpose: This study investigated the microbial microleakage through temporary restorative materials (Coltosol, IRM, Vidrion R) after post space preparation.Methods: Forty-two maxillary anterior human teeth were prepared and obturated with guttapercha and Sealapex using the lateral condensation technique, with 4mm of apical obturation remaining. Calcium hydroxide paste was used to fill the post space preparation, and 4mm of the coronal portion was restored with the temporary filling materials. Six specimens were totally sealed (negative control) and six specimens were not filled (positive control). An in vitro microbial leakage test (MLT) with a split chamber (upper/lower chambers) was used. Microbial microleakage was observed daily for 90 days. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests.Results: Coltosol, IRM, and Vidrion R allowed microbial microleakage after 19 to 89 days. Conclusion: All temporary fillings and intracanal dressings did not prevent the penetration of microorganisms to the root apex.

Objetivo: Este estudo investigou a infiltração microbiana em materiais restauradores provisórios (Coltosol, IRM, Vidrion R) após preparo para retentores intrarradiculares. Metodologia: Quarenta e dois dentes humanos anteriores superiores foram preparados e obturados com guta-percha e Sealapex utilizando a técnica da condensação lateral, mantendo 4mm de remanescente apical de obturação. Foi usada pasta de hidróxido de cálcio para preencher o espaço criado para os pinos, deixando um espaço de 4mm na cervical a ser preenchido pelos materiais testados. Seis espécimes foram totalmente impermeabilizados (controle negativo) e seis espécimes não foram obturados (controle positivo). Um teste de infiltração microbiana (MLT) com uma câmara dividida em duas partes foi usado neste ensaio. A infiltração microbiana foi verificada diariamente durante 90 dias. Os dados obtidos foram analisados pelos testes de Kruskal-Wallis e de Mann-Whitney. Resultados: Coltosol, IRM e Vidrion R permitiram infiltração microbiana após 19 a 89 dias. Conclusão: O material restaurador temporário e a medicação intracanal não preveniram a penetração de microrganismos até o ápice radicular.

Influence of eugenol-containing temporary restorations on the microleakage of total-etch and self-etching adhesive systems / Influência de restaurações temporárias contendo eugenol na microinfiltração de sistemas adesivos convencional e autocondicionante

Purpose: This in vitro study evaluated the influence of zinc oxide-eugenol temporary cement (ZOE-TC) on the sealing ability of composite restorations using two adhesive systems. Methods: Standard Class V cavities were prepared in 20 bovine incisors and restored with either ZOE-TC (IRM®) or eugenol-free cement (Cavit®) (n=10/temporary cement type). After 7 days, five teeth per material group were restored using Single Bond® (SB) and five using Adper Prompt® (AP). The cavities were filled with composite (Filtek Z-250), thermal cycled (500 cycles), immersed in basic fuchsine solution, and longitudinally sectioned. Dye penetration was evaluated using optical-microscopy and scored. Data were analyzed by Kruskal-Wallis test (P = 0.05). Results: Overall, leakage in dentin was similar to that in enamel. In enamel margins, only the group with Cavit® cement associated with AP presented significant higher leakage. In dentin margins, AP exhibited higher leakage than the groups restored with SB; there was no significant difference between eugenol-free cement and ZOE-TC. Conclusion: In general, SB showed better marginal sealing than AP, and ZOE-TC did not increase dye leakage. Eugenol in the temporary cement did not affect the marginal sealing of adhesive restorations.

Objetivo: Este estudo in vitro avaliou a influência de um cimento restaurador temporário à base de óxido de zinco-eugenol (CT-OZE) no selamento marginal de restaurações diretas, utilizando dois sistemas adesivos. Metodologia: Cavidades classe V foram preparadas em 20 incisivos bovinos e restauradas com dois cimentos temporários, CT-OZE (IRM®) ou cimento livre de eugenol (Cavit®) (n=10/cimento temporário). Após sete dias, cinco dentes de cada grupo de cimento temporário foram restaurados utilizando o sistema Single Bond® (SB) e os demais cinco com o sistema Adper Prompt® (AP). As cavidades foram restauradas com resina composta (Filtek Z-250), termocicladas (500 ciclos), imersas em fucsina básica e longitudinalmente seccionadas. A penetração do corante foi avaliada em microscópio ótico. Os dados foram analisados por teste de Kruskal-Wallis (P = 0,05). Resultados: A infiltração em dentina foi similar à do esmalte. Em esmalte, o grupo com Cavit® e AP apresentou infiltração significativamente maior. Em dentina, AP exibiu maior infiltração que SB, e não houve diferença entre CT-OZE e Cavit®. Conclusão: Em geral, SB produziu melhor selamento marginal que AP, e CT-OZE não aumentou a penetração de corante. A presença de eugenol no material restaurador temporário não afetou o selamento marginal de restaurações adesivas.

[The incidence of local plaque retentive factors in chronic periodontitis]. / Lokális plakkretenciós tényezok elofordulási gyakorisága krónikus parodontitisben.

One of the leading local risk factors for chronic periodontitis is the presence of plaque retentive factors in the oral cavity. The main objective of the study was to assess how the local irritation and plaque retention caused by untreated carious lesions, subgingival and approximal overhanging crown margins can affect the attachment loss at patients with chronic periodontitis. The incidence of plaque retentive factors were evaluated on 200 panoramic radiographs randomly selected from the archive of the Department of Periodontology. On the radiographs each fully erupted tooth were studied under magnifying glasses (1:2 magnification), and the distance between CEJ and the most coronal bone level was measured with a ruler with mm scales. The quality of restorations were evaluated based on the approximal adaptation of their margins. During the clinical examination the presence of local plaque retentive factors were registered by tooth, and the radiological alveolar bone level were recorded around both the healthy and restored or filled teeth. Statistical analyzes were made with linear regression analysis and ANOVA. Only 177 out of the randomly selected 200 radiographs met the incursion criteria and could be evaluated. The average age of patients was 49.98 years and the average approximal bone loss was 5.439 mm, showing increasing tendency with age. The 177 patients had a total of 3618 teeth and 1407 teeth presented plaque retentive factors including 164 untreated approximal carious lesions, and 1243 faulty restorations with approximal overhangs or open margins. Radiographically 82.5% of the restorations had incorrect approximal marginal adaptation. The majority of the untreated carious lesions occurred in the molar as well as in the front regions. The average bone loss at the teeth with faulty restorations were higher than at the sound teeth. 113 patients had an average bone loss higher than >4 mm. In those patients the differences between sound and restored teeth were smaller than those in the groups of patients with mild bone loss. Nevertheless neither group showed statistically significant differences between restored and sound teeth. In mild to moderate periodontitis local plaque retentive factors, overhanging crown margins or carious lesions are decisive aggregating factors both in gingivitis and periodontitis, especially in the susceptible population. In severe periodontitis according to our data there were only minimal differences between the attachment level around sound teeth and teeth with faulty restorations and local plaque retentive factors.

Comparison of temperature increase in the pulp chamber during the polymerization of materials used for the direct fabrication of provisional restorations.

STATEMENT OF PROBLEM: Polymerization of resin materials used for the fabrication of provisional restorations is associated with an exothermic reaction. This temperature rise may present a serious biological problem, since it can cause iatrogenic thermal trauma to the pulp. PURPOSE: This in vitro study compared the temperature increase in the pulp chamber of a molar placed in contact with different resins used for the direct fabrication of provisional restorations. MATERIAL AND METHODS: Polymethyl methacrylate (Jet), polyethyl methacrylate (Snap), polyvinylethyl methacrylate (Trim), Bis-acrylic composite (Protemp II), and a VLP urethane dimethacrylate (Revotec LC) were compared with respect to their exothermic reaction properties during polymerization. A mandibular molar prepared for a complete coverage restoration was placed in an acrylic resin block. A thermal probe connected to a digital thermometer was placed into the pulp chamber. Specimens were submerged in a water bath to simulate intraoral conditions. The provisional resin materials tested were measured and mixed according to manufacturer's instructions. The resin mixture was placed into a vacuum-formed acetate template and was then positioned on the prepared molar tooth. The temperature was recorded during polymerization at 30-second intervals until it was evident that the peak temperature had been reached. Temperature increase was measured ( degrees C) for both the initial crown fabrication and the reline procedures. Data were analyzed with descriptive statistics, 1-way analysis of variance, and Tukey Honestly Significant Difference tests (alpha=.05). RESULTS: One-way ANOVA revealed significant differences (F=57.010, P<.0001) in temperature rise for different provisional resin materials. Mean temperature increase for the provisional crown fabrication ranged from 37.76 degrees C for the polyvinylethyl methacrylate to 39.40 degrees C for the polymethyl methacrylate. Mean temperature rise for the reline procedures ranged from 36.80 degrees C for the polyvinylethyl methacrylate to 37.69 degrees C for the polymethyl methacrylate. All of the tested materials produced an exothermic chemical reaction. CONCLUSIONS: Polymethyl methacrylate produced the higher exothermic reaction in both initial crown fabrication and reline procedures. Polyethyl methacrylate, polyvinylethyl methacrylate, and Bis-acrylic resins tested were not significantly different from each other.

Efeito do selamento dentinário imediato e de materiais restauradores provisórios na resistência de união à dentina / Effect of immediate dentin sealing and provisional restorations on bond strength to dentin

Objetivo: O objetivo do estudo foi avaliar, in vitro, o efeito da técnica do selamento dentinário imediato com um sistema adesivo de 5º geração, e da aplicação intermediária de dois materiais provisórios, na resistência de união à tração sobre a dentina. Materiais e método: A coroa de 75 dentes incisivos bovinos foram incluídas em resina acrílica quimicamente ativada, sendo a superfície vestibular desgastada até exposição da dentina. A superfície dentinária recebeu acabamento com lixas de granulação 400 e 600, sendo os dentes divididos em 5 grupos (n = 15): Grupo 1: Single Bond (controle); Grupo 2: Temp Bond NE + Single Bond; Grupo 3: Single Bond + Temp Bond NE + Single Bond; Grupo 4: Fermit + Single Bond; Grupo 5: Single Bond + Fermit + Single Bond. Os grupos 3 e 5 reproduziram a técnica de selamento imediato da dentina. Um cone de resina composta (Z250) foi construído sobre o adesivo. Após armazenamento por 24 horas a 37ºC em água destilada, os corpos-de-prova foram submetidos ao teste de resistência à tração em máquina de ensaio universal. Resultados: De acordo com a Análise de Variância, não houve diferença estatisticamente significativa nos valores médios de resistência à tração entre os grupos (p > 0,05): grupo 1 (16,84 MPa); grupo 2 (14,27 MPa); grupo 3 (17,27 MPa); grupo 4 (14,87 MPa); grupo 5 (12,97 MPa). Conclusão: A técnica de selamento imediato da dentina com o sistema adesivo Single Bond, assim como os materiais provisórios Temp Bond NE e Fermit, não influenciaram significativamente os valores de resistência de união à dentina.