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OBJECTIVE: There is a need for an ideal polishing system for resin composite restorations. The purpose of this study was to investigate the influence of polishing instruments on the surface texture of light-cured resin composites. METHODS AND MATERIALS: Four polishing systems-Compomaster (Shofu), Silicone Points C Type (Shofu), Super-Snap (Shofu), and Enhance Finishing and Polishing System (Dentsply/DeTrey)-were used to polish the flat surface of cylindrical blocks made of 3 different resin composites: Beautifil (Shofu), Clearfil AP-X (Kuraray Medical), and Lite-Fil II A (Shofu). The average surface roughness (Ra) and surface gloss (Gs60 degrees) were determined. Scanning electron microscopic observations of the polished specimens were made. The polished samples were immersed in a 0.3% acid rhodamine B solution for 1 week, and change in color was determined. RESULTS: The multiple-step systems, Enhance and Super-Snap, resulted in the best surface finishes. A new single-step point, Compomaster, ranked third in surface finish but was significantly better than the older point system, Silicone Points C. The color-staining experiments showed that there were no significant differences between the Compomaster system and the multiple-step systems, which were all significantly better than the older polishing point. CONCLUSION: The newly introduced 1-step polishing point has the ability to polish resin composites as effectively as multistep polishing systems. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The purpose of this study was to determine the degradation of 10% carbamide peroxide within the first hour of use and the effect of pellicle on the degradation of carbamide peroxide in vivo. METHOD AND MATERIALS: Fifteen subjects were assigned to wear nightguard trays filled with bleaching gel for 0.5, 2.5, 5.0, 10.0, 20.0, 40.0, and 60.0 minutes under 2 conditions: (1) subjects did not receive a prophylaxis before each bleaching treatment (pellicle was assumed to be present on the tooth surface); and (2) subjects received prophylaxis to remove pellicle from the tooth surface. At each evaluation time, 3 types of sample were collected: (1) a 'grab sample,' a sample of gel taken with a spatula from the reservoir of the tray on the maxillary right central incisor; (2) the remaining gel from the tray; and (3) the remaining gel scraped from the teeth. The collected gel samples were analyzed for the amount of peroxide using the United States Pharmacopeia-accepted method. Subjects were asked not to swallow the saliva during treatment but to expectorate into a beaker. The collected saliva was analyzed to determine the amount of peroxide. This sample represented the approximate amount of peroxide that subject would ingest during treatment. RESULTS: Pellicle did not affect the degradation of carbamide peroxide for the teeth or grab samples. The degradation of carbamide peroxide was exponential, except during the first 5 minutes, when the degradation rate was much higher. The saliva collected from subjects during use of the bleaching tray revealed an average of 2.1 mg of carbamide peroxide for 1 hour of bleaching treatment. CONCLUSION: The degradation rate is not affected by the removal of the pellicle. [ABSTRACT FROM AUTHOR]

Nerve transfers, nerve grafts, and tendon transfers have been used to restore shoulder active external rotation in patients with brachial plexus birth injuries. Traditionally used nerve surgery techniques are nerve transfer from the spinal accessory nerve to a suprascapular nerve (SSN) or nerve grafting from C5 to the SSN. However, results are often suboptimal. A more distal and more targeted transfer from the spinal accessory nerve directly to the infraspinatus branch of the SSN has previously been described and mid-term outcomes are encouraging. Herein, we describe a modification of this technique with accompanying step-by-step intraoperative photographs., Competing Interests: Conflicts of Interest and Source of Funding: The authors report no conflicts of interest and no source of funding., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Advances in pediatric TB care are promising, the result of decades of advocacy, operational and clinical trials research, and political will by national and local TB programs in high-burden countries. However, implementation challenges remain in linking policy to practice and scaling up innovations for prevention, diagnosis, and treatment of TB in children, especially in resource-limited settings. There is both need and opportunity to strengthen clinician confidence in making a TB diagnosis and managing the various manifestations of TB in children, which can facilitate the translation of evidence to action and expand access to new tools and strategies to address TB in this population. This review aims to summarize existing guidance and best practices for clinicians and health care providers in low-resource, TB-endemic settings and identify resources with more detailed and actionable information for decision-making along the clinical cascade to prevent, find, and cure TB in children.

The aim of the present study was to develop measurement methods to evaluate occlusal differences in digitally-articulated and hand-articulated models in final occlusal planning for orthognathic surgery. A total of 10 (five class II and five class III) previously treated orthognathic cases were analysed by three oral and maxillofacial surgeon investigators, creating a total of thirty cases. Investigators used physical models to create a preferred hand-held final occlusion, which were then scanned and saved utilising a Trios 3® scanner (3Shape). Models were digitally disarticulated and sent back to investigators after a period of at least a month for digital articulation. Novel measurements of dental roll, pitch, and translational differences were performed by an independent engineer using Materialise 3-Matic® software. Statistical analysis was used to evaluate translational differences, the effect of deformity, and inter-investigator variation. A mean (SD) translational difference of 1.58 mm (1.14) mm was seen between the thirty digital and hard-articulated cases analysed. Minimal difference was seen in roll and pitch between hand articulation and digital articulation. A significant translational difference was seen in class III cases compared with class II (p = 0.0006) but not in roll or pitch. There was no significant difference seen between investigators related to translation (p = 0.18), roll (p = 0.09), or pitch (p = 0.17). Digital articulation yielded similar results to hand held in this pilot study. Using measurement techniques described in larger cohorts, its accuracy can be validated using currently available technology., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

Child and adolescent tuberculosis (TB) has been long neglected by TB programs but there have been substantive strides in prioritizing TB among these populations in the past two decades. Yet, gaps remain in translating evidence and policy to action at the primary care level, ensuring access to novel tools and approaches to diagnosis, treatment, and prevention for children and adolescents at risk of TB disease. This article describes the progress that has been made and the gaps that remain in addressing TB among children and adolescents while also highlighting pragmatic approaches and the role of multisectoral partnerships in facilitating integration of innovations into routine program practice.

Introduction: Providing more convenient and patient-centred options for service delivery is a priority within global HIV programmes. These efforts improve patient satisfaction and retention and free up time for providers to focus on new HIV diagnoses or severe illness. Recently, the coronavirus disease 2019 (COVID-19) pandemic precipitated expanded eligibility criteria for these differentiated service delivery (DSD) models to decongest clinics and protect patients and healthcare workers. This has resulted in dramatic scale-up of DSD for antiretroviral therapy, cotrimoxazole and tuberculosis (TB) preventive treatment. While TB treatment among people living with HIV (PLHIV) has traditionally involved frequent, facility-based management, TB treatment can also be adapted within DSD models. Such adaptations could include electronic tools to ensure appropriate clinical management, treatment support, adherence counselling and adverse event (AE) monitoring. In this commentary, we outline considerations for DSD of TB treatment among PLHIV, building on best practices from global DSD model implementation for HIV service delivery., Discussion: In operationalizing TB treatment in DSD models, we consider the following: what activity is being done, when or how often it takes place, where it takes place, by whom and for whom. We discuss considerations for various programme elements including TB screening and diagnosis; medication dispensing; patient education, counselling and support; clinical management and monitoring; and reporting and recording. General approaches include multi-month dispensing for TB medications during intensive and continuation phases of treatment and standardized virtual adherence and AE monitoring. Lastly, we provide operational examples of TB treatment delivery through DSD models, including a conceptual model and an early implementation experience from Zambia., Conclusions: COVID-19 has catalysed the rapid expansion of differentiated patient-centred service delivery for PLHIV. Expanding DSD models to include TB treatment can capitalize on existing platforms, while providing high-quality, routine treatment, follow-up and patient education and empowerment., (© 2021 The Authors. Journal of the International AIDS Society published by John Wiley & Sons Ltd on behalf of the International AIDS Society.)

Objective : The study evaluated the water sorption (WSP) and water solubility (WSL) characteristics of different luting agents over a 180-day water storage period. Materials and Methods : Nine luting materials, i.e., conventional resin cement: Panavia F (PF), Rely X ARC (RA), self-adhesive resin cement: Rely X Unicem (RU), Breez (BZ), Maxcem Elite (MX), BisCem (BC) and resin-modified glass ionomer cement: FujiCem (FC), FujiPlus (FP) Rely X luting plus (RL) were assessed and fifty-two-disc specimens of each material were fabricated. All specimens were desiccated until a constant weight (W0) was reached. Thirteen specimens for each luting material were then randomly assigned to one of the four water immersion periods (7, 30, 90, and 180 days). After each period, the specimens were removed from the water and weighed to get W1. The samples were again desiccated for a second time and W 2 was measured. Both WSP and WSL were determined by the following equations: WSP (%) = (W 1 - W 2 ) × 100/W 0 and WSL (%) = (W 0 - W 2 ) × 100/W 0 . Assessments were performed following ISO standards. ANOVA was used to assess the effect of luting agent and time period on water sorption and solubility. Pair-wise comparisons were adjusted using Tukey's multiple comparison procedure. A significance level of 0.05 was used for all statistical tests. Results : The highest mean WSP and WSL (WSP/WSL) were demonstrated by resin-modified glass-ionomers (RL 18.32/3.25, FC 17.08/4.83, and FP 14.14/1.99), while resin luting agents showed lower WSP and WSL results (PF 1.6/0.67 and RA 1.76/0.46), respectively. The self-adhesive agents exhibited a wide range of WSP and WSL values (RU 1.86/0.13, BZ 4.66/0.93, and MX 3.68/1.11). Self-adhesive cement showed lower WSP and WSL compared with the resin-modified glass-ionomers ( p < 0.05). All the materials reached equilibrium after 90-days. Conclusions : Resin-based luting materials have the lowest sorption and solubility. Rely X Unicem self-adhesive luting materials were comparable to resin luting materials for WSL and WSP. Resin-modified glass-ionomer showed the highest water sorption and solubility compared with both resin and self-adhesive materials.

Multidrug-resistant (MDR) TB is more difficult to diagnose and treat compared with drug-susceptible TB. Young children are at greater risk of severe TB disease and death when treatment is delayed compared to adults. We sought to describe characteristics of children (<13 years) diagnosed with MDR TB between 2008-2010 in three South African provinces and assess factors associated with pre-treatment loss to follow-up. We matched laboratory and medical records at treatment facilities to identify pre-treatment loss and examined demographic and clinical characteristics for association with loss. Categorical variables were examined for association using Pearson's x2 or Fisher's exact test, employing Bonferroni correction for multiple pairwise comparisons. Between 2008-2010, 156 children were diagnosed with laboratory-confirmed MDR TB. Only 44% (n = 69) were documented as having received treatment. Young children (<2 years) (47/59, 80%), children with extrapulmonary (EP) TB (27/34, 79%), and children diagnosed at general hospitals (60/97, 62%) were most likely to be lost before treatment. Children most vulnerable to death from TB are most likely to be lost before treatment, possibly leading to underestimates of disease burden, case notifications, and poor outcomes among this population. Point-of-care diagnosis and robust follow-up may reduce pre-treatment loss in this population., Competing Interests: The authors have declared that no competing interests exist.

Extensively drug-resistant tuberculosis (XDR TB) has extremely poor treatment outcomes in adults. Limited data are available for children. We report on clinical manifestations, treatment, and outcomes for 37 children (<15 years of age) with bacteriologically confirmed XDR TB in 11 countries. These patients were managed during 1999-2013. For the 37 children, median age was 11 years, 32 (87%) had pulmonary TB, and 29 had a recorded HIV status; 7 (24%) were infected with HIV. Median treatment duration was 7.0 months for the intensive phase and 12.2 months for the continuation phase. Thirty (81%) children had favorable treatment outcomes. Four (11%) died, 1 (3%) failed treatment, and 2 (5%) did not complete treatment. We found a high proportion of favorable treatment outcomes among children, with mortality rates markedly lower than for adults. Regimens and duration of treatment varied considerably. Evaluation of new regimens in children is required.

Background: An estimated 32,000 children develop multidrug-resistant tuberculosis (MDR-TB; Mycobacterium tuberculosis resistant to isoniazid and rifampin) each year. Little is known about the optimal treatment for these children., Methods and Findings: To inform the pediatric aspects of the revised World Health Organization (WHO) MDR-TB treatment guidelines, we performed a systematic review and individual patient data (IPD) meta-analysis, describing treatment outcomes in children treated for MDR-TB. To identify eligible reports we searched PubMed, LILACS, Embase, The Cochrane Library, PsychINFO, and BioMedCentral databases through 1 October 2014. To identify unpublished data, we reviewed conference abstracts, contacted experts in the field, and requested data through other routes, including at national and international conferences and through organizations working in pediatric MDR-TB. A cohort was eligible for inclusion if it included a minimum of three children (aged <15 years) who were treated for bacteriologically confirmed or clinically diagnosed MDR-TB, and if treatment outcomes were reported. The search yielded 2,772 reports; after review, 33 studies were eligible for inclusion, with IPD provided for 28 of these. All data were from published or unpublished observational cohorts. We analyzed demographic, clinical, and treatment factors as predictors of treatment outcome. In order to obtain adjusted estimates, we used a random-effects multivariable logistic regression (random intercept and random slope, unless specified otherwise) adjusted for the following covariates: age, sex, HIV infection, malnutrition, severe extrapulmonary disease, or the presence of severe disease on chest radiograph. We analyzed data from 975 children from 18 countries; 731 (75%) had bacteriologically confirmed and 244 (25%) had clinically diagnosed MDR-TB. The median age was 7.1 years. Of 910 (93%) children with documented HIV status, 359 (39%) were infected with HIV. When compared to clinically diagnosed patients, children with confirmed MDR-TB were more likely to be older, to be infected with HIV, to be malnourished, and to have severe tuberculosis (TB) on chest radiograph (p < 0.001 for all characteristics). Overall, 764 of 975 (78%) had a successful treatment outcome at the conclusion of therapy: 548/731 (75%) of confirmed and 216/244 (89%) of clinically diagnosed children (absolute difference 14%, 95% confidence interval [CI] 8%-19%, p < 0.001). Treatment was successful in only 56% of children with bacteriologically confirmed TB who were infected with HIV who did not receive any antiretroviral treatment (ART) during MDR-TB therapy, compared to 82% in children infected with HIV who received ART during MDR-TB therapy (absolute difference 26%, 95% CI 5%-48%, p = 0.006). In children with confirmed MDR-TB, the use of second-line injectable agents and high-dose isoniazid (15-20 mg/kg/day) were associated with treatment success (adjusted odds ratio [aOR] 2.9, 95% CI 1.0-8.3, p = 0.041 and aOR 5.9, 95% CI 1.7-20.5, p = 0.007, respectively). These findings for high-dose isoniazid may have been affected by site effect, as the majority of patients came from Cape Town. Limitations of this study include the difficulty of estimating the treatment effects of individual drugs within multidrug regimens, only observational cohort studies were available for inclusion, and treatment decisions were based on the clinician's perception of illness, with resulting potential for bias., Conclusions: This study suggests that children respond favorably to MDR-TB treatment. The low success rate in children infected with HIV who did not receive ART during their MDR-TB treatment highlights the need for ART in these children. Our findings of individual drug effects on treatment outcome should be further evaluated., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: DF, MG, and MvDB are staff members of the World Health Organization (WHO). AJGP's institution, Stellenbosch University, has received funds from the US National Institutes of Health for an observational study of the pharmacokinetics and safety of key second-line TB medications in children, for which AJGP is the Principal Investigator. AJGP's institution has also received funds from Otsuka Pharmaceuticals for implementation of pediatric trial of the novel TB drug delamanid; AJGP is the PI for his site for this trial.

Objective: To describe outcomes of HIV-infected pediatric patients with drug-resistant tuberculosis (DR TB)., Methods: Demographic, clinical and laboratory data from charts of pediatric patients treated for DR TB during 2005-2008 were collected retrospectively from 5 multi-DR TB hospitals in South Africa. Data were summarized, and Pearson χ test or Fisher exact test was used to assess differences in variables of interest by HIV status. A time-to-event analysis was conducted using days from start of treatment to death. Variables of interest were first assessed using the Kaplan-Meier method. Cox proportional hazard models were fit to estimate crude and adjusted hazard ratios., Results: Of 423 eligible participants, 398 (95%) had culture-confirmed DR TB and 238 (56%) were HIV infected. A total of 54% were underweight, 42% were male and median age was 10.7 years (interquartile range: 5.5-15.3). Of the 423 participants, 245 (58%) were successfully treated, 69 (16%) died, treatment failed in 3 (1%), 36 (9%) were lost to follow-up and 70 (17%) were still on treatment, transferred or had unknown outcomes. Time to death differed by HIV status (P = 0.008), sex (P < 0.001), year of tuberculosis diagnosis (P = 0.05) and weight status (P = 0.002). Over the 2-year risk period, the adjusted rate of death was 2-fold higher among participants with HIV compared with HIV-negative participants (adjusted hazard ratio = 2.28; 95% confidence interval: 1.11-4.68)., Conclusions: Male, underweight and HIV-infected children with DR TB were more likely to experience death when compared with other children with DR TB within this study population.

Setting: National Tuberculosis (TB) Program sites in northwest Cambodia., Objective: To evaluate the impact of Xpert(®) MTB/RIF at point of care (POC) as compared to non-POC sites on the diagnostic evaluation of people living with the human immunodeficiency virus (PLHIV) with TB symptoms and patients with possible multidrug-resistant (MDR) TB., Design: Observational cohort of patients undergoing routine diagnostic evaluation for TB following the rollout of Xpert., Results: Between October 2011 and June 2013, 431 of 822 (52%) PLHIV with TB symptoms and 240/493 (49%) patients with possible MDR-TB underwent Xpert. Xpert was more likely to be performed when available as POC. A smaller proportion of PLHIV at POC sites were diagnosed with TB than at non-POC sites; however, at POC sites, a higher proportion of those diagnosed with TB were bacteriologically positive. There was poor agreement between Xpert and other tests such as smear microscopy and culture. Overall, the evaluation of patients with possible MDR-TB increased following Xpert rollout, yet for patients confirmed as having drug resistance on drug susceptibility testing, only 46% had rifampin resistance that would be identified with Xpert., Conclusion: Although utilization of Xpert was low, it may have contributed to an increase in evaluations for possible MDR-TB and a decline in empiric treatment for PLHIV when available as POC.

Injury to the maxillofacial region continues to place a burden on hospital care in New Zealand, with maxillofacial fractures often being associated with both a significant social cost and personal morbidity. This article describes the characteristics, aetiology and treatment patterns in a tertiary maxillofacial centre in New Zealand during a 10-year period. Over the observation period, a total of 1,975 cases were treated, with a male-to-female ratio of 4:1. The highest incidence was in the 20-29-year-age group. Interpersonal violence (IPV) was the most common aetiology, observed in 54.5% overall, and more common among males than females (58% and 38% respectively; P&lt;0.001). Falls were the most common cause of injury among older females (those aged 50+). Comparison to an earlier analysis shows that IPV-related maxillofacial trauma has increased significantly at this tertiary centre, increasing from 36.2% of cases in 1989-2000, to 54.5% in 2004-2013. There remains an urgent need for appropriate health promotion to reduce interpersonal violence, as well as an increase in the staffing numbers of maxillofacial units in New Zealand.

Keratocystic odontogenic tumour (KOT or KCOT) is defined by the WHO to be 'a benign uni- or multicystic, intraosseous tumour of odontogenic origin'. In 2005, the World Health Organization renamed the lesion; previously known as an odontogenic keratocyst (OKC) as the KCOT. WHO recommends the term KCOT as it reflects its neoplastic nature. In this case report, a 21-year-old female with a histologically proven large parakeratinised KCOT of the right mandible underwent treatment that involved a 14-month period of decompression, followed by enucleation (with Carnoys application) of the residual cyst. During the period of decompression, a custom made removable mandibular chrome-cobalt appliance was used to hold the decompression tube in the oral cavity.

Objective: To describe the demographic and clinical characteristics of children and adolescents diagnosed with resistance to any anti-tuberculosis drug (drug-resistant tuberculosis; DR-TB) in South Africa., Design: We retrospectively reviewed medical records of all children (<13 years) and adolescents (13 to <18 years) with DR-TB at specialty hospitals in four South African provinces from 2005 to 2010., Results: During the review period, 774 children and adolescents (median age 11.3 years) were diagnosed with DR-TB at selected facilities. A high proportion of patients had a history of previous TB treatment (285/631; 45.2%), human immunodeficiency virus (HIV) infection (375/685; 54.7%), contact with a TB case (347/454; 76.4%), and smear-positive (443/729; 60.8%), cavitary (253/680, 38.7%) disease. Eighty-two per cent of patients with HIV infection received antiretroviral therapy. Of 626 patients diagnosed with multidrug-resistant TB (MDR-TB), 561 (89.6%) received a regimen consistent with national guidelines; the median length of treatment was 22 months (IQR 16-25). Among 400 patients with any DR-TB and a known outcome, 20.3% died during treatment., Conclusion: Pediatric DR-TB in these provinces is characterized by complex clinical features at diagnosis, with one in five children dying during treatment. History of previous treatment and contact with a TB patient indicate opportunities for earlier diagnosis and treatment to improve outcomes.

Objective: To describe the implementation and utilization of the Xpert (®) MTB/RIF (Xpert) assay to diagnose tuberculosis (TB) among people living with the human immunodeficiency virus/acquired immune-deficiency syndrome (HIV/AIDS, PLHA) in Cambodia., Design: Following the rollout of Xpert, an evaluation was conducted in four provinces of Cambodia from March to December 2012 to determine the utilization, performance, and turnaround time (TAT) of Xpert among PLHA. Data were collected from paper-based patient registers., Results: Of 497 PLHA with a positive TB symptom screen, 357 (72%) were tested with smear microscopy, and 250 (50%) with Xpert; 25 (10%) PLHA tested with Xpert were positive for TB and none were rifampicin-resistant. The utilization of Xpert increased from 23% to 75%, with a median TAT of 1 day. Across districts, utilization ranged from zero to 85%, while the TAT ranged from zero to 22 days., Conclusion: While early data show increasing utilization of Xpert for PLHA with a positive symptom screen, most patients underwent smear microscopy as an initial diagnostic test. Training delays and challenges associated with specimen referral may have contributed to variability in Xpert uptake and TAT, particularly for sites without onsite Xpert testing. Enhanced programmatic support, particularly for specimen referral and results reporting, may facilitate appropriate utilization.

We linked results from the Fourth Botswana National Drug Resistance Survey (DRS), 2007-2008, to patient records from the national Electronic Tuberculosis Registry to determine treatment outcomes. Of 915 new patients, 651 (71%) had treatment data available. Completion or cure was achieved for 10/15 (67%, 95%CI 42-85) with isoniazid monoresistance, (6/16, 38%, 95%CI 18-61) with multidrug resistance, while 73% (391/537, 95%CI 69-76) were susceptible to first-line drugs. The analysis was limited because of unavailable treatment records and undocumented outcomes. Prospective analyses following DRSs should be considered to ensure adequate outcome data.

This in vitro study evaluated the toothbrush abrasion wear, three-body Alabama wear and two-body pin-on-disc wear of four commercial indirect resin composites. Enamel shades of Radica (R), Sculpture Plus (S), Belleglass-NG (B) and Gradia Indirect (G) were used. For measuring wear due to toothbrush abrasion, six specimens of each group were fabricated, then brushed in a toothbrush abrasion machine for 20,000 cycles. Material loss was determined by weighing and conversion to volume loss. Three-body wear was measured on six samples for each group using an Alabama-type wear testing machine for 400,000 cycles. Wear depth was measured with a contact profilometer. For two-body wear, five disc specimens were prepared and tested in a two-body wear-testing machine against hydroxypatite sliders for 25,000 cycles. Data were analyzed with one-way analysis of variance (ANOVA) and Tukey test (alpha=0.05). Wear was the highest in Sculpture Plus by all three methods tested and the lowest wear was observed in Belleglass-NG. No statistical difference in wear was noted from Radica.

Purpose: The purpose of this article is to review basic information about the alloys used for fabricating metal-ceramic restorations in dentistry. Their compositions, properties, advantages, and disadvantages are presented and compared. In addition to reviewing traditional noble-metal and base-metal metal-ceramic alloys, titanium and gold composite alloys are also discussed., Materials and Methods: A broad search of the published literature was performed using Medline to identify pertinent current articles on metal-ceramic alloys as well as articles providing a historical background about the development of these alloys. Textbooks, the internet, and manufacturers' literature were also used to supplement this information., Results: The review discusses traditional as well as more recently-developed alloys and technologies used in dentistry for fabricating metal-ceramic restorations. Clear advantages and disadvantages for these alloy types are provided and discussed as well as the role that compositional variations have on the alloys' performance. This information should enable clinicians and technicians to easily identify the important physical properties of each type and their primary clinical indications., Conclusions: A number of alloys and metals are available for metal-ceramic use in dentistry. Each has its advantages and disadvantages, primarily based on its specific composition. Continuing research and development are resulting in the production of new technologies and products, giving clinicians even more choices in designing and fabricating metal-ceramic restorations.

Objectives: The aim of this study was to test the hypothesis that the residual stresses in a zirconia-based bilayer dental composite system can be tailored through heat treatment above and below the glass transition temperature of glass veneers., Methods: Ceramic bilayer disc specimens were prepared from a zirconia core and a glass veneer. Each bilayer ceramic group was heat treated 40 degrees C below, 20 degrees C and 40 degrees C above and at the glass transition temperature of the glass veneer, and cooled using a fast or a slow cooling rate. Specimens were tested for flexure strength using a biaxial bending fixture. Residual stresses were calculated using a fracture mechanics approach., Results: Heat treatments produced significant differences (p < or =0.05) between the mean flexural strengths of the heat treatment groups when the specimens were cooled using a fast cooling rate. However, there was not a significant difference (p >0.05) between the mean flexural strengths of the heat treatment groups when a slow cooling rate was used. Fractures initiated from the veneer surfaces of the specimens., Significance: Heat treatment above and below the glass transition temperature of the veneer layer, and the cooling rate have a significant effect on the flexural strength of the bilayer ceramic laminates. The existence of residual compressive stress is the most likely reason for the observed strength increases. Residual stresses can be modified using the elastic-viscoelastic relaxation behavior of a glass veneer.

The optimal degree of curing throughout the bulk of a visible light-activated dental resin composite is acknowledged to be important to the clinical success of a resin composite restoration. Unfortunately, the dentist has no means of monitoring the cure of the resin surfaces not directly exposed to the curing light. Techniques, such as the layered buildup of restorations in 2 mm increments with longer activation times than 20 seconds, have been suggested. This study investigated the depth of cure (DOC) of a commercial resin composite in three types: flowable, hybrid and packable and in three shades: B1, A3 and D3 after 20 second activation with a quartz halogen light (620 mW/cm2). Depth of cure was measured by scraping the uncured material and by using a Knoop Hardness profile, starting from the surface exposed to the light. Using a minimum Knoop Hardness ratio of 0.8 bottom/top only, the flowable in shade B1 achieved a 2 mm DOC. Using the less restrictive scraping test, only the B1 shade of flowable and hybrid significantly exceeded a 2 mm DOC. Knoop Hardness at the DOC obtained by scraping ranged from 55%-70% of the top surface hardness. These data suggest that a 2 mm buildup layering technique may not result in adequate curing of the bottom layer for such a wide range of materials and that manufacturers need to provide quantitative information about DOC at specific activation times and light intensities for their entire range of resin materials and shades so that the dentist can devise a placement technique that will ensure adequate cure of the bulk of a restoration.

The antimicrobial and anticariogenic properties of a copper varnish (experimental mixture of Doc's Best Red Copper cement and Copalite varnish, Cooley and Cooley, Ltd, Houston, TX, USA: designated in this study as "Copper Seal") on the root surface were evaluated in an in vitro microbial caries model. Fifty-six human root specimens were prepared from anterior teeth and randomly divided into four groups: Groups 1 and 3-Copper Seal; Group 2-chlorhexidine varnish, the positive control (Cervitec, Ivolcar Vivadent, Schaan, Liechtenstein) and Group 4-a negative control that received no treatment. The varnishes were painted in Groups 1, 2 and 3, then visually removed after 24 hours in Group 1. The specimens were demineralized in a microbial caries model for five days. Plaque was collected from the specimens to obtain bacterial colonization numbers, then the specimens were sectioned and analyzed for lesion extent using Confocal Laser Scanning microscopy. There were no significant differences (p>0.05) among the four groups in terms of bacterial count. Regarding caries lesion development, the group with copper varnish visually removed (Group 1) and the non-treated group (Group 4) had significantly greater total area caries lesions and total lesion fluorescence than the copper varnish without removal group (Group 3) and the chlorhexidine group (Group 2). Therefore, it was concluded that copper and chlorhexidine varnishes have anticariogenic effects on root surfaces, as tested in this model.

This in vitro study compared the effectiveness between ProFile 29 Series rotary system followed by continuous wave obturation and the Endo-Eze system. Thirty-six human mandibular canine and premolar teeth were randomly separated into 2 groups of 18. Each tooth was embedded in resin and sectioned at 2, 6, and 12 mm from the apex and viewed under the scanning electron microscope at 50-150x magnification. The percentages of canal space occupied by gutta-percha, sealer, debris, and voids were measured and analyzed with Image J software. Results were calculated by using an analysis of variance model with fixed effects for method, distance, and distance interaction. Repeatability of measurements and intraclass correlation coefficients were calculated. These results demonstrated that obturation with the continuous wave technique achieved significantly more gutta-percha occupying the canal space than the Endo-Eze system. Under the conditions of this study, the continuous wave technique was less likely to exhibit voids than the Endo-Eze technique. Furthermore, neither the Profile Series 29 nor the Endo-Eze system cleaned and shaped elliptical canals consistently.

This investigation compared microleakage of teeth obturated with gutta-percha and teeth obturated with Resilon by using a fluid filtration model. Forty-six human, single-rooted, mandibular premolars were studied. Teeth were randomly assigned to 2 experimental groups of 21 teeth each, designated as group G (gutta-percha) and group R (Resilon). Two control groups, both containing 2 teeth, served as positive and negative controls. Group G, gutta-percha and AH 26 sealer, and group R, Resilon and Epiphany sealer, were obturated by using warm vertical condensation. The specimens were tested for microleakage with an in vitro fluid filtration apparatus at 10 psi at 4 intervals: 1, 7, 30, and 90 days. A two-way repeated measures analysis of variance model with fixed effects for group, time, and group by time interaction was used to analyze microleakage data. This study demonstrated that canals obturated with Resilon and Epiphany sealer leaked statistically less than canals obturated with gutta-percha and AH 26 sealer at day 1 (P < .0014), day 7 (P < .0002), day 30 (P < .0015), and day 90 (P < .0170). The mean fluid microleakage for both group G and group R increased from day 1 to day 90. The results showed that Resilon is a suitable replacement for gutta-percha as a root canal filling material on the basis of its increased resistance to fluid microleakage.

The purpose of this study was to compare the contents of root canals obturated with gutta percha and AH-26 sealer (Dentsply, Tulsa, OK) to canals obturated with the Resilon and Epiphany (Pentron, Wallingford, CT) system. Canal contents were assessed by determining the percentage of canal space occupied by core material, sealer, voids, and debris. Forty extracted human maxillary anterior teeth were instrumented, and the teeth were randomly assigned to either the gutta percha/AH 26 group or the Epiphany/Resilon group. Canals were obturated, and the teeth were subsequently embedded in resin and sectioned horizontally at 2, 4, and 6 mm from the anatomic apex. Sections were photographed by using a low vacuum scanning electron microscope. Image-J (Wayne Rasband; National Institute of Health, Bethesda, MD) software was used to quantify the proportion of core material, sealer, voids, and debris in each canal. Percentages and statistical comparisons for each method were compared. There were no significant differences found among the two groups in terms of the percentage of core (p = 0.9), sealer (p = 0.58), debris (p = 0.999), or voids (p = 1.00). Additionally, there were no differences in the percentage of core material, sealer, debris, or voids at any of the examined levels (2, 4, or 6 mm).

Endodontic sealers should demonstrate adhesive properties to dentin to reach the objectives of the obturation of the canal space and seal the canal space both apically and coronally, thus decreasing the chance of endodontic treatment failure. Adhesion to dentin with bonding to the tooth structure in the canal may provide greater resistance to tooth fracture and greater clinical longevity of an endodontically treated tooth. In this study, human single-canal canines were endodontically treated and obturated with two different endodontic obturation systems (Epiphany/Resilon system and gutta-percha/AH 26). Thirty roots (divided into two groups) were horizontally sliced for a push-out strength test, which was performed from apical to coronal in the universal testing machine. Differences in push-out bond strength between the two different material systems were obtained using repeated measures analysis of variance on ranks. Gutta-percha had significantly higher push-out bond strength than Epiphany (p<0.0001).

This study investigated the influence of thermal cycling on the dentin bond strengths of single-step self-etch adhesive systems. The Absolute, Clearfil Tri-S Bond, G-Bond and One-Up Bond F Plus systems were used. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied to the prepared dentin surfaces, and they were light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (4 mm in diameter and 2 mm in height) and light irradiated for 30 seconds. Bonded specimens were divided into three groups and subjected to different storage conditions as follows: 37 degrees C water for 24 hours; 37 degrees C water for 24 hours followed by 10,000 thermal cycles between 5 degrees C and 60 degrees C or 37 degrees C water for 24 hours followed by 20,000 thermal cycles between 5 degrees C and 60 degrees C. Ten samples per group were tested in a shear mode at a crosshead speed of 1.0 mm/minute. Analysis of variance and Tukey's HSD test at the 0.05 significance level were used to compare the three storage conditions for each adhesive system. After 24 hours storage in water, the mean dentin bond strengths ranged from 11.4 MPa to 17.1 MPa. The Clearfil Tri-S Bond system showed the highest bond strength. After 10,000 thermal cycles, the mean bond strengths remained unchanged except for those of the Clearfil Tri-S Bond system, which significantly increased. Significant decreases in bond strength were observed for the Absolute and One-Up Bond F Plus systems after 20,000 thermal cycles. Failure mode was commonly due to adhesive breakdown associated with partial cohesive failure of the adhesive resin. From the results of this study, in terms of simplifying the clinical procedure, the benefit of using single-step self-etch systems might be acceptable.

This study investigated the influence of thermal cycling on the enamel bond strength of single-step self-etch adhesive systems. The systems used were Absolute, Clearfil tri-S Bond, G-Bond and One-Up Bond F Plus. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied on the prepared enamel surfaces and light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (ø4x2 mm) and light irradiated for 30 seconds. Thirty specimens per adhesive systems were divided into 1 of 3 test groups (n=10) following storage in water at 37 degrees C for 24 hours. The specimens were then stored in 37 degrees C water for 24 hours, followed by thermal cycling 10,000 and 20,000 times between 5 degrees C and 60 degrees C. After each storage condition, the specimens were tested in shear mode at a crosshead speed of 1.0-mm/minute. One-way ANOVAs and Tukey HSD test at a level of 0.05 were conducted. After 24 hours of water storage, the mean enamel bond strengths ranged from 11.3 to 16.9 MPa, and Clearfil tri-S Bond showed significantly higher bond strength. After thermal cycling, the mean bond strengths ranged from 8.3 to 20.7 MPa. The changes in enamel bond strengths were different among the adhesive systems tested. Failure modes after the test were commonly adhesive failure associated with partial cohesive failure adhesive in resin. With a careful choice of adhesive systems, the benefit to using single-step self-etch systems in terms of simplifying the clinical procedure might be acceptable, even after thermal stresses.

Purpose: To investigate the influence of utilizing films with different oxygen transmission rates (O2-GTR) on Knoop hardness and toothbrush abrasion of resin cements for luting., Methods: Four dual-activated, composite-type resin cements, and a chemically activated PMMA-type resin cement, were used. Three different types of barrier films (Techbarrier HI, Harden Film N130, and Lix-2) were used. Resin cement was mixed and inserted into a cylindrical mold (4 mm in diameter, 3 mm in height), then chemically activated. The specimens were stored in the dark at 37 +/- 1 degrees C, 90 +/- 5%RH conditions for 1 hour. Knoop hardness on the top surface of the resin cement was measured with a microhardness tester. The top surface of specimens (8 mm in diameter, 3 mm in height) polymerized under the same conditions were used for toothbrush abrasion testing. One-way ANOVA followed by Tukey HSD test (P< 0.05) were done., Results: When the cement surface was covered by low O2-GTR film, a significant increase in Knoop hardness and resistance to toothbrush abrasion was observed for the dual activated, composite-type resin cements, but not for the chemically activated PMMA type resin cement. From the results of this study, the use of low O2-GTR matrix barrier films for the dual activated, composite-type resin cements could be effective in eliminating the oxygen inhibited layer on the cement surface.

This article discusses the fracture resistance of 4 post and core systems including a combined obturator/post system before and after fatigue loading. The obturator/post demonstrated the highest fracture resistance values. The use of a combined obturator/post with a single resin endodontic sealer/luting cement seems promising.

Objective: The purpose of this study was to determine the effect of Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) paste on demineralization of bovine enamel by measuring changes in the ultrasound transmission velocity., Methods: The enamel specimens were prepared by cutting bovine teeth into blocks. The specimens were stored in 0.1 M lactic acid buffer solution (pH 4.75, Ca 0.75 mM, P 0.45 mM) for 10 min twice a day, and then stored in the artificial saliva (pH 7.0). Other specimens were stored in a 10-times diluted solution of CPP-ACP paste and a placebo paste without CPP-ACP for 10 min, followed by 10 min immersion into a demineralization solution twice a day before storage in the artificial saliva. The propagation time of longitudinal ultrasonic waves was measured by a Pulser-Receiver (Model 5900, Panametrics) with a transducer (V112, Panametrics). Six specimens were used for each condition, and one-way ANOVAs followed by the Tukey HSD tests (alpha = 0.05) were done., Results: The sonic velocity was found to decrease with time for specimens stored in the demineralization solution. On the other hand, a significant increase in sonic velocity was found for specimens stored in the CPP-ACP solution., Conclusions: From the result of this study, it was suggested that the conditions of de- and remineralization of the enamel structure could be measured non-destructively by using an ultrasonic pulse method. It could be concluded that the inorganic components contained in high concentrations in CPP-ACP acted to enhance remineralization of the enamel structure.

This study examined the effect of air-drying time of adhesives on the dentin bond strength of several single-application self-etch adhesive systems. The adhesive/resin composite combinations used were: Adper Prompt L-Pop/Filtek Z250 (AP), Clearfil Tri-S Bond/Clearfil AP-X (CT), Fluoro Bond Shake One/Beautifil (FB), G-Bond/Gradia Direct (GB) and One-Up Bond F Plus/Palfique Estelite (OF). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied according to each manufacturer's instructions followed by air-drying time for 0 (without air-drying), 5 and 10 seconds. After light irradiation of the adhesives, the resin composites were condensed into a mold (phi4x2 mm) and polymerized. Ten samples per test group were stored in 37 degrees C distilled water for 24 hours; they were then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Tukey's HSD tests (alpha = 0.05) were done. FE-SEM observations of the resin/dentin interface were also conducted. Dentin bond strength varied with the different air drying times and ranged from 5.8 +/- 2.4 to 13.9 +/- 2.8 MPa for AP, 4.9 +/- 1.5 to 17.1 +/- 2.3 MPa for CT, 7.9 +/- 2.8 to 13.8 +/- 2.4 MPa for FB, 3.7 +/- 1.4 to 13.4 +/- 1.2 MPa for GB and 4.6 +/- 2.1 to 13.7 +/- 2.6 MPa for OF. With longer air drying of adhesives, no significant changes in bond strengths were found for the systems used except for OF. Significantly lower bond strengths were obtained for the 10-second air-drying group for OF. From FE-SEM observations, gaps between the cured adhesive and resin composites were observed for the specimens without the air drying of adhesives except for OF. The data suggests that, with four of the single-application self-etch adhesive systems, air drying is essential to obtain adequate dentin bond strengths, but increased drying time does not significantly influence bond strength. For the other system studied, the bond strength of the non-air dried group was not significantly different from the five second drying time, but prolonged drying was very detrimental to bond strength. For all five of the systems studied, a five-second air-drying time appeared to be appropriate.

This study examined the relationship between delay in composite placement over cured adhesives and the dentin bond strength of several single-application self-etch adhesive systems. The adhesive system/resin composite combinations used were: Adper Prompt L-Pop/Filtek Z250 (AP), AQ Bond Plus/Metafil C (AQ), Fluoro Bond Shake One/Beautifil (FB), G-Bond/Solare (GB), One-Up Bond F Plus/Palfique Estelite (OF), Xeno IICF Bond/Xeno CF (XE). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. The adhesives were applied according to each manufacturer's instructions, and resin pastes were condensed into a mold (ø4x2 mm) immediately, and 1, 2, 5 and 10 minutes after light irradiation of the adhesives. Ten samples per test group were stored in 37 degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Tukey's HSD test (alpha = 0.05) was done. SEM observations of the dentin surface after the tests were also conducted. Dentin bond strength ranged from 9.5 +/- 2.2 to 14.0 +/- 2.4 MPa for AP, 7.3 +/- 2.2 to 12.2 +/- 3.1 MPa for AQ, 10.0 +/- 3.5 to 16.3 +/- 2.4 MPa for FB, 11.4 +/- 1.5 to 16.3 +/- 1.2 MPa for GB, 14.2 +/- 3.4 to 15.1 +/- 3.0 MPa for OF and 11.5 +/- 2.4 to 15.9 +/- 2.2 MPa for XE. Except for OF, no significant differences were found among the 2 to 10 minute delayed placement groups for the systems used. Significant lower bond strengths were obtained for the immediate placement groups except for OF. From SEM observations, cohesive failure of the dentin surface was more pronounced with the longer delay in placement. The data suggest that delayed composite placement over the cured adhesives are suggested for optimum dentin bond strength of single-application self-etch adhesive systems.

Light Emitting Diode (LED) curing units are attractive to clinicians, because most are cordless and should create less heat within tooth structure. However, questions about polymerization efficacy have surrounded this technology. This research evaluated the adequacy of the depth of cure of pit & fissure sealants provided by LED curing units. Optilux (OP) and Elipar Highlight (HL) high intensity halogen and Astralis 5 (A5) conventional halogen lights were used for comparison. The Light Emitting Diode (LED) curing units were Allegro (AL), LE Demetron I (DM), FreeLight (FL), UltraLume 2(UL), UltraLume 5 (UL5) and VersaLux (VX). Sealants used in the study were UltraSeal XT plus Clear (Uclr), Opaque (Uopq) and Teethmate F-1 Natural (Kclr) and Opaque (Kopq). Specimens were fabricated in a brass mold (2 mm thick x 6 mm diameter) and placed between two glass slides (n=5). Each specimen was cured from the top surface only. One hour after curing, four Knoop Hardness readings were made for each top and bottom surface at least 1 mm from the edge. The bottom to top (B/T) KHN ratio was calculated. Groups were fabricated with 20 and 40-second exposure times. In addition, a group using a 1 mm-thick mold was fabricated using an exposure time of 20 seconds. Differences between lights for each material at each testing condition were determined using one-way ANOVA and Student-Newman-Keuls Post-hoc test (alpha=0.05). There was no statistical difference between light curing units for Uclr cured in a 1-mm thickness for 20 seconds or cured in a 2 mm-thickness for 40 seconds. All other materials and conditions showed differences between light curing units. Both opaque materials showed significant variations in B/T KHN ratios dependent upon the light-curing unit.

A core foundation system is frequently used in endodontically treated teeth that suffer excessive loss of the coronal portion of their structure. The volumetric shrinkage of core foundation resins may create marginal gaps that influence the bonding ability and longevity of a restored tooth. Little is known about how activation conditions of resin core foundation resin pastes affect their volumetric shrinkage. This study evaluated the influence of light intensity and light activation duration on volumetric shrinkage of direct core foundation resins. Two dual- and one light-activated core foundation resin pastes were employed. The material was placed in a Teflon mold 4 mm in diameter and 2 mm in height and extruded into a water filled dilatometer. The specimens were then light activated and the change in height of the meniscus of water was recorded using a charged-coupled device camera. The average volumetric shrinkage of the core foundation resins after 180 seconds ranged from 1.53% to 2.63%. For all materials tested, there was a tendency for increased volumetric shrinkage with increased light activation time and intensity. The results of this study indicate that the volumetric change of core foundation resins is influenced by the time and intensity of light activation.

Purpose: To determine the influence of interchanging self-etching primers and bonding agents on dentin bond strengths., Methods: Four commercially available self-etching primer dentin bond systems, Clearfil SE Bond (CB), Imperva Fluoro Bond (FB), Mac Bond II (MB), and Unifil Bond (UB) were used. Bovine mandibular incisors were mounted in self-curing resin and the facial dentin surfaces were ground wet on 600-grit SiC paper. The self-etching primers were applied, and four different types of bonding agents were applied on the primed dentin surfaces and cured. The resin-based composites were condensed into the mold (ø4x2 mm) on the dentin surface and light cured. Ten specimens per test group were stored in 37 degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. Two-way ANOVA followed by Tukey's multiple comparison tests were done. The temperature change of the bonding agents mixed with the primers was monitored during the exothermic polymerization reaction according to the method of ISO standard #4049. The peak temperature and the time required to reach peak temperature were recorded., Results: When different primers were tested with each bonding agent, only the combination of FB with CBP showed statistically lower bond strengths than the other combinations. When different bonding agents were tested with each primer, CB exhibited the highest bond strengths. The only other statistically significant difference was again the combination of FB and CB. Peak temperature decreased and the time required to reach peak temperature increased with the primer/bonding agent combinations compared to the controls. No exotherm was seen for the combination of FB and CBP.

This study evaluated the effect of NaOCl treatment of etched air-dried dentin on the bond strength and state of monomer penetration. Ten percent NaOCl was applied after rinsing the etchant and air drying the dentin surface. Wet bonded, untreated teeth were used as a control. The resin composite was bonded and stored in 37 degrees C water for 24 hours, then shear tested. One-way ANOVA, followed by the Duncan test, was done. For Raman microscopy, bonded specimens were cut parallel to the dentinal tubules and polished. Raman spectra were successively recorded along lines perpendicular to the dentin-adhesive interface. The decreased bond strengths found with air-dried dentin increased with NaOCl treatment, but the highest bond strength was obtained with wet bonding. From Raman spectroscopy, the widths of demineralized dentin decreased with prolonged NaOCl treatment time. The patterns of gradual transition of components differed among the groups.

Carious lesions around crown margins sometimes lead to failure of fixed prosthodontics. This study examined the influence of metal conditioner application on a dentin surface prior to bonding procedures, using two-step self-etching primer systems. Commercially available metal conditioners and self-etching primer dentin bonding systems were used. Bovine mandibular incisors were mounted in self-curing resin, and the facial dentin surfaces were ground wet on 600-grit SiC paper. The metal primers were applied on the dentin surface followed by bonding procedures with four different types of self-etching primer systems. The resin composites were condensed into a mold on the dentin surface and light activated. Ten specimens per test group were stored in 37 degrees C water for 24 hours; they were then shear tested at a crosshead speed of 1.0 mm/minute. Two-way ANOVA and Tukey's HSD tests were done. When the metal conditioners were applied on dentin surfaces before bonding procedures, there was a tendency for decreased dentin bond strengths compared to those obtained with the controls. This tendency differed among the combinations of metal conditioners and self-etching primer systems used. Appropriate surface treatments are required to get optimum bond strengths with the use of technique sensitive bonding systems combined with metal conditioners.

The anti-cariogenic properties of three fluoride-releasing materials on root surfaces were evaluated using two different caries models. Standardized cavities were prepared in dentin specimens and restored with either glass-ionomer, resin-modified glass-ionomer, polyacid-modified resin composite or resin composite material. Two groups of 56 specimens were demineralized using a microbial caries model for three days, while another 56 specimens were demineralized using a chemical demineralization model for three days. Lesions around the restorations were measured with a confocal laser scanning microscope. Glass ionomers demonstrated significant anti-cariogenic properties when exposed to the chemical model. However, no significant anti-cariogenic properties were observed with the microbial caries model. In conclusion, the fluoride releasing materials showed different anti-cariogenic properties in root surfaces under the different caries models, suggesting that caution should be exercised when trying to extrapolate the results of in vitro studies to the clinical situation.

This study determined the influence of interchanging adhesive resins and self-etching primers on the mechanical properties of adhesive resins. Four commercially available two-step self-etching primer systems were used. To measure microtensile strength, 0.5-mm thick dumbbell-shaped slabs of each combination of adhesive resin and self-etching primer were prepared. After 24 hours storage in 37 degrees C distilled water, these specimens were subjected to microtensile testing at a crosshead speed of 1.0 mm/minute. Fourier transformation infrared spectroscopy was used to determine the degree of conversion. The percentage of residual double bonds, including pendant and monomeric double bonds, was calculated by comparing the obtained ratio against uncured adhesive resin. The degree of conversion of the adhesive resins was obtained by subtracting the %C=C from 100%. Two-way ANOVAs, followed by Tukey tests, were done. The microtensile strengths and degree of conversion varied with different combinations of self-etching primer and adhesive resin. Numerically, the highest microtensile strengths were obtained when the primer/adhesive resin combinations from the same manufacturer were used. When the different combinations of self-etching primers and adhesive resins were mixed, the microtensile strength and degree of conversion of the adhesive resins tended to decrease for some combinations. Within the limitations of this study, which was far removed from clinical situations, the role of the self-etching primers on the mechanical properties of adhesive resins should be considered to create an authentic resin-dentin interface.

Statement of Problem: Little is known about how various polymerization combinations of dual-polymerized adhesives and resin core foundation pastes affect dentin bond strength., Purpose: This study examined the influence of different polymerization modes of dual-polymerized resin direct core foundation systems on dentin bond strength using bovine dentin., Material and Methods: Two commercially available dual-polymerized resin direct core foundation systems, Clearfil DC Core and UniFil Core, were studied. Bovine mandibular incisors were mounted in autopolymerizing resin and the facial dentin surfaces were ground wet on 600-grit SiC paper. Dentin surfaces were treated according to manufacturer's recommendations, and dual-polymerized adhesives were applied and dual-polymerized (control) or only chemically polymerized. The core foundation resins were condensed into the mold (4 x 2-mm) and were also either dual-polymerized or only chemically polymerized. Eighty specimens (n=10) were stored in 37 degrees C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/min in a universal testing machine. Fourier transformation infrared spectroscopy was used to measure the degree of conversion of dual-polymerized resin core foundation pastes with both modes of polymerization. One- and 2-way ANOVA, Tukey HSD tests, and Student t -tests were performed (alpha=.05)., Results: The highest mean bond strengths (+/-SD) were obtained when the adhesives and resin pastes were dual-polymerized for both core foundation systems (14.6 +/- 2.1 MPa for Clearfil DC Core, 15.6 +/- 2.2 MPa for UniFil Core). Chemical polymerization of dual-polymerized adhesives and resin pastes resulted in significantly lower bond strength (2.8 +/- 0.6 MPa for Clearfil DC Core, 8.1 +/- 2.2 MPa for UniFil Core) ( P <.001). The degree of conversion for the resin pastes decreased significantly ( P <.05) when only chemical polymerization was employed, from 81.5% to 76.1% for Clearfil DC Core and 86.7% to 81.2% for UniFil Core., Conclusion: The data suggests that the dentin bond strengths of the dual-polymerized resin direct core foundation systems are highest when both adhesive and resin core paste are dual polymerized.

Resin composites are considered susceptible to environmental conditions that might affect bond strength. This study investigated the influence of relative humidity and temperature on the dentin bond strength of newly developed one-application adhesive systems. Bonding systems employed in this study were five commercial one-application adhesive systems. Labial surfaces of bovine incisors were ground wet on 600-grit SiC paper. The teeth were transferred to a controlled temperature and humidity chamber and the specimens were prepared in six different environmental conditions, A) 25 +/- 0.5 degrees C, 50 +/- 5% RH, B) 25 +/- 0.5 degrees C, 80 +/- 5% RH, C) 25 +/- 0.5 degrees C, 95 +/- 5% RH, D) 37 +/- 0.5 degrees C, 50 +/- 5% RH, E) 37 +/- 0.5 degrees C, 80 +/- 5% RH, F) 37 +/- 0.5 degrees C, 95 +/- 5% RH. The dentin surfaces were treated according to each manufacturer's instructions. Resin composites of each bonding system were condensed into a mold and light irradiated. After storage in 37 degrees C water for 24 hours, 10 specimens per group were tested in a shear mode in a testing machine at a crosshead speed of 1.0 mm/minute. Statistical analysis was carried out with one-way ANOVA followed by Duncan's multiple range tests at a p-value of 0.05. The dentin bond strengths of one-application adhesive systems decreased with increasing RH. These data suggest that the relative high humidity in the oral environment needs consideration in developing clinical procedures for management of these one-application adhesive systems.

Microleakage testing continues to be undertaken using a variety of techniques and methodologies. This study compared four microleakage tracers to determine if a difference exists in their ability to demonstrate microleakage on a single dental amalgam restorative material by testing in two phases. Class V amalgam restorations were placed on the facial surfaces of 105 extracted human premolars with all margins in enamel. The teeth were stored at 37 degrees C in water for two weeks except during thermocycling for 2500 cycles between 8 degrees C and 48 degrees C. The teeth were prepared for microleakage testing by sealing the external surfaces with nail polish and tinfoil, leaving the restoration and surrounding 1 mm exposed. In the first phase, four groups of 15 teeth were randomly assigned to 0.5% basic fuchsin dye, 2.0% fluorescent dye, 1.5% reactive orange 14 and 45Ca. In the second phase, another three groups of 15 teeth were immersed in 45Ca, then immersed in one of the remaining three tracers. Ridit analysis and Newman-Keuls multiple comparisons were used to compare the groups at a significance level of 0.05. The results indicate that there are differences in observed microleakage between tracers and there is no statistical influence on dye tracers by initial immersion in 45Ca.

Purpose: Though reduction in bond strength after tooth whitening has been reported, little is known about it's effect on enamel bond strength of two-step bonding systems that exclude phosphoric acid etching prior to bonding agent application. The purpose of this study was to determine the effect of whitening procedure using an in-office whitening agent on enamel bond strength of self-etching primer systems., Methods: Three self-etching primer systems, Imperva Fluoro Bond, Mac Bond II, Clearfil SE Bond, and a one-bottle adhesive system Single Bond as a control material, were used. Bovine mandibular incisors were mounted in self-curing resin and the facial enamel or dentin surfaces were ground wet on 600-grit SiC paper. An in-office whitening agent, Hi-Lite was applied on the tooth surface according to the manufacturer's instruction. Bonding procedures were done soon after rinsing off the whitening agent or after 24 hours storage in distilled water. Specimens without whitening procedure were prepared as controls. Fifteen specimens per test group were stored in 37 degrees C distilled water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Duncan multiple range test were used for statistical analysis of the results., Results: For the specimens made soon after rinsing off the whitening agent, a significant decrease in enamel bond strength was observed for all the bonding systems used. For the specimens made after 24 hours storage in water, a small decrease in enamel bond strength was observed and no significant differences were found compared to those of controls (without whitening). From the results of this study, enamel bond strengths of the self-etching primer systems might be affected to a lesser degree after rinsing with water followed by 24 hours storage in water.

Objectives: This study evaluated the influence of water on the volumetric dimensional change of six direct placement core build-up materials by using Archimedes' principle., Methods: The effect on dimensional change due to the setting reaction was determined through the use of a silicone oil storage medium. The materials used were two dual-cured resin composites (CoreStore and Build-It FR), two chemically activated resin composites (CorePaste and Ti-Core), one metal-reinforced glass ionomer cement (Ketac-Silver), and one resin-modified glass ionomer (Fuji II LC Core). Using the manufacturers' instructions for each material, cylindrical specimens were prepared with dimensions of 7+/-0.1 mm in diameter and 2+/-0.1 mm in height. Each material had four groups (n = 5) based on storage conditions; silicone oil at 23 and 37 degrees C and distilled water at 23 and 37 degrees C. A 0.01 mg resolution balance was used to determine volumetric dimensional change using an Archimedean equation. Measurements were made 30 min after mixing, and at the time intervals of 1, 14, and 56 days., Results: All materials exhibited dimensional change. Ketac-Silver had the most shrinkage in silicone oil and Fuji II LC showed the highest expansion in distilled water. The glass ionomer materials showed more change than did any of the resin composite materials., Significance: Current direct placement core materials show variation in the amount of volumetric dimensional change seen over a period of 56 days.

Purpose: The purpose of this study was twofold: 1. To compare two different research models for simulating a traumatic anterior tooth fracture: the blunt trauma method (standard method) and an AL2O3 sectioning method (experimental method). 2. To compare the bond strength of tooth fragments bonded with resin modified glass ionomer vs. a light cured composite resin., Methods: Two hundred bovine incisors were used in the study and kept in plain tap water throughout. The study consisted of five basic steps: 1. Fracture of the teeth by either blunt trauma (chisel and hammer) or AL2O3 sectioning disc. 2. Luting of the fractured fragments back to the teeth using either a composite resin or resin modified glass ionomer. 3. Thermocycling of the repaired teeth. 4. Dislodging the teeth to determine the strength of repair. 5. Determination of fracture type., Results: One-way ANOVA revealed a statistically significant difference in the forces required to fracture the resin modified glass ionomer and composite resin regardless of whether the teeth were originally fractured with the blunt force method (p=0.030) or the disc sectioning method (p=.001). One-way ANOVA also revealed a statistically significant difference between the forces required for fracture by blunt trauma and the disc fracture techniques with the resin modified glass ionomer group (p=0.000345). However, there was no significant difference when the two techniques were compared for the composite resin (p= 0.2941)., Conclusions: 1. The resin modified glass ionomer was significantly stronger than the composite resin when both the blunt trauma and the disc fracture techniques were employed. 2. The study's results do not support substituting the ease of the AL2O3 disc for the more time-consuming blunt trauma method.

This in vitro study compared three different methods to evaluate detectable levels of microleakage in Class II restorations placed with five commercially available packable resin composites: Alert, Glacier, Pyramid, Solitaire 2 and SureFil. A flowable resin composite, Flow-It, was used to line all packable composites. The hybrid resin composite Z100 was also included. The adhesive system used with all groups was Scotchbond MultiPurpose Plus. Standard Class II cavities were prepared on the mesial (enamel margins) and distal (dentin margins) sides of the teeth with no communication between them. Based on a power analysis, 180 permanent human molars were randomly assign to each of six groups with 30 specimens per group. All restorative materials were placed following manufacturers' recommendations. Following restoration and thermocycling, the specimens were stored at room temperature in solutions of 45Ca, methylene blue and rhodamine B, sequentially. Microleakage was ordinal scored as 1 (no penetration), 2 (penetration up to one-third of the cervical floor), 3 (penetration beyond one-third of the cervical floor to the axial wall) and 4 (penetration along the axial wall) by two independent evaluators. Analysis of the occlusal surfaces was also accomplished following the same scheme. In this study, tracers/dyes were evaluated for differences in penetration using generalized estimating equation methodology applied to cumulative logistic regression models. The results showed that Rhodamine B detected more microleakage than 45Ca or methylene blue, and 45Ca generally detected more microleakage than methylene blue.

The difficulty related to achieving a balance between wet and dry dentin makes the dentin bonding technique extremely sensitive. This study evaluated the effect of rewetting dried dentin with two commercial desensitizing agents (Protect and HurriSeal) on the dentin shear bond strength of three total-etch dentin bonding agents (Syntac Single-Component, OptiBond Solo Plus and Prime & Bond NT) and compared both to applying these same bonding agents to moist dentin and dry dentin. Each bonding agent was paired with an appropriate resin composite from the same manufacturer (Table 1). Recently extracted, formalin-treated caries-free human molars were used. The occlusal surface of each tooth was ground to create a flat dentin surface. Then, each tooth was mounted in acrylic. Twelve groups (n = 15) were prepared: 1) Syntac Single-Component with Heliomolar resin composite (SSC/H) to moist dentin; 2) SSC/H to dry dentin; 3) SSC/H to dried dentin rewet with Protect; 4) SSC/H to dried dentin rewet with HurriSeal; 5) OptiBond Solo Plus with Point 4 resin composite (OBS+/P4) to moist dentin; 6) OBS+/P4 to dry dentin; 7) OBS+/P4 to dried dentin rewet with Protect; 8) OBS+/P4 to dried dentin rewet with HurriSeal; 9) Prime & Bond NT with TPH Spectrum resin composite (PBNT/TPH) to moist dentin; 10) PBNT/TPH to dry dentin; 11) PBNT/THP to dried dentin rewet with Protect and 12) PBNT/TPH to dried dentin rewet with HurriSeal. Groups 1, 5 and 9 were placed according to manufacturers' instructions (moist dentin) as control groups. All the other groups received a 15-second air blast after etching and prior to applying the one bottle adhesive or desensitizer and one bottle adhesive. Resin composite cylinders [4 mm in diameter and 2 mm in height] were then placed. The specimens were stored in distilled water at 37 degrees C for 24 hours prior to thermocycling 2,500 times (at 8 degrees C and 48 degrees C). Shear bond strengths (SBSs) were measured one week after fabrication by using a circular knife-edge and crosshead speeds of 0.5 mm/minute. Failure modes of debonded specimens were determined under a stereomicroscope (30x). Failed specimens with the low and high shear bond strengths in each group were evaluated under a low vacuum Scanning Electron Microscope (SEM-LV). One-way ANOVA and Tukey's tests were used to compare the different conditions for each bonding system. In the Syntac Single-Component bonding agent groups, there was no significant difference in shear bond strength between the control (15.73 MPa), dry (18.11 MPa) and HurriSeal (16.18 MPa) specimens. Protect specimens showed significantly lower shear bond strength (6.39 MPa). In the OptiBond Solo Plus bonding agent groups, there was no significant difference between the control (20.79 MPa) and the HurriSeal (21.29 MPa) groups, and both groups had significantly greater bonds than the dry (14.13MPa) and Protect (9.57 MPa) groups. In the Prime & Bond NT bonding agent groups, the shear bond strength of the HurriSeal group (20.73 MPa) was significantly higher than the other groups: control (8.05 MPa), dry (5.73 MPa) and Protect (5.45 MPa).

Adhesion of resin composites into enamel is currently believed to rely on infiltration of bonding resin into the porous zone, establishing micromechanical retention to etched enamel. This study investigated the change in chemical composition of the enamel/resin interface using a laser Raman microscopic system (System-2000, Renishaw). Two-step bonding systems, Mac Bond II (Tokuyama Corp), Clearfil Mega Bond and Single Bond (3M/ESPE) were employed. Resin composites were bonded to bovine enamel with bonding systems and sectioned through the bonded interface. The sectioned surfaces were then polished with diamond pastes down to 1.0 microm particle size. Raman spectra were successively recorded along a line perpendicular to the enamel/ resin interface. The sample stage was moved in 0.2 microm increments on a computer-controlled X-Y precision table. Additional spectra from samples of enamel and cured bonding resins were recorded for reference. The relative amounts of the hydroxyapatite (960cm(-1), P-O), bonding agent (640cm(-1), aromatic ring) and alkyl group (1450cm(-1), C-H) in the enamel/resin bonding area were calculated. From Raman spectroscopy, a gradual decrease in hydroxyapatite was observed, and it was estimated to extend 2.2-2.6 microm for Mac Bond II, 1.2-1.6 pm for Clearfil Mega Bond and 5.2-5.6 microm for Single Bond. Furthermore, the enamel/resin interface represents a gradual transition of bonding agent from the resin to tooth side. Evidence of poor saturation of adhesive resin in etched enamel with Single Bond was detected. From the results of this study, non-uniform resin infiltration into etched enamel was detected and the degree of resin infiltration was found to be different among the bonding systems used.