Fifteen-year survival of resin-bonded vs full-coverage fixed dental prostheses.

PURPOSE: We clarified cumulative survival and event-free rates of resin-bonded fixed dental prostheses (RBFDPs) and compared them to those of fixed dental prostheses (FDPs) to refine risk factors for non-survival/event and use of tooth extraction after the period of non-survival/event. METHODS: Study subjects were selected among all patients who consecutively attended the Fixed Prosthodontic Clinic of Okayama University Hospital. Eligible patients were those who received 3-unit metal-framed 2-retainer (wing-wing) RBFDPs or conventional full-coverage FDPs (RBFDPs/FDPs: 129/177 prostheses). Data were analyzed by Kaplan-Meier analysis with the log-rank test, Mann-Whitney test, chi-square test, and Cox proportional hazards analysis. RESULTS: The 15-year cumulative survival rates were 66.5% for the RBFDP group and 61.6% for the FDP group, which were not significantly different (p = 0.59). The 15-year cumulative event-free rates were 53.4% for the RBFDP group and 59.2% for the FDP group, which were not significantly different (p = 0.52). No significant risk factors related to non-survival and event-free of RBFDPs/FDPs were identified in the analysis model using treatment method, sex, age, number of remaining teeth, and treatment site as explanatory variables. The number of cases in which RBFDPs/FDPs resulted in non-survival due to abutment tooth extraction was significantly lower in RBFDPs (p < 0.01). Further, the abutment tooth as a non-vital tooth was identified as a risk factor for RBFDPs/FDPs resulting in non-survival due to abutment tooth extraction. CONCLUSIONS: The present study is the first to indicate RBFDP as a prosthetic treatment option which should be selected for patients with slight or no abutment tooth decay.

Advanced Statistical Analyses to Reduce Inconsistency of Bond Strength Data.

This study was designed to clarify the interrelationship of factors that affect the value of microtensile bond strength (µTBS), focusing on nondestructive testing by which information of the specimens can be stored and quantified. µTBS test specimens were prepared from 10 noncarious human molars. Six factors of µTBS test specimens were evaluated: presence of voids at the interface, X-ray absorption coefficient of resin, X-ray absorption coefficient of dentin, length of dentin part, size of adhesion area, and individual differences of teeth. All specimens were observed nondestructively by optical coherence tomography and micro-computed tomography before µTBS testing. After µTBS testing, the effect of these factors on µTBS data was analyzed by the general linear model, linear mixed effects regression model, and nonlinear regression model with 95% confidence intervals. By the general linear model, a significant difference in individual differences of teeth was observed ( P < 0.001). A significantly positive correlation was shown between µTBS and length of dentin part ( P < 0.001); however, there was no significant nonlinearity ( P = 0.157). Moreover, a significantly negative correlation was observed between µTBS and size of adhesion area ( P = 0.001), with significant nonlinearity ( P = 0.014). No correlation was observed between µTBS and X-ray absorption coefficient of resin ( P = 0.147), and there was no significant nonlinearity ( P = 0.089). Additionally, a significantly positive correlation was observed between µTBS and X-ray absorption coefficient of dentin ( P = 0.022), with significant nonlinearity ( P = 0.036). A significant difference was also observed between the presence and absence of voids by linear mixed effects regression analysis. Our results showed correlations between various parameters of tooth specimens and µTBS data. To evaluate the performance of the adhesive more precisely, the effect of tooth variability and a method to reduce variation in bond strength values should also be considered.

Evaluation of genetic factors involved in nocturnal electromyographic activity of masticatory muscles in twins.

OBJECTIVES: The objectives of this study were to assess sleep bruxism events by directly recording electromyographic activity during sleep and to reveal the relative importance of genetic and environmental factors involved in sleep bruxism in twins. MATERIAL AND METHODS: The subjects consisted of 108 twins (mean age 22.2 ± 6.4 years). Electromyographic activity of temporalis muscles during sleep was evaluated using a portable automatic sleep bruxism analyzer (Grindcare 3.0, Medotech A/S), and recordings were carried out for at least three consecutive nights. Quantitative genetic statistics based on structural equation modeling was utilized to estimate variance components. RESULTS: Monozygotic twin-pair correlation for the number of nocturnal electromyographic activities recorded in this study (r = 0.463, P = 0.009) was higher than dizygotic twin-pair correlation (r = 0.103, P = 0.725). The proportion of total phenotypic variance in the liability of sleep bruxism to attribute to genetic influences, related to the electromyographic activities, was 48 % (95 % CI 17-95 %) and to unique environmental influences was 52 % (95 % CI 28-82 %). CONCLUSIONS: Additive genetic effects may be a contributing factor to the occurrence of nocturnal EMG activity associated with sleep bruxism. CLINICAL RELEVANCE: A greater understanding of the contribution of genetic factors could have beneficial uses, including enhanced accuracy of sleep bruxism diagnosis, management of sleep bruxism, and enhanced estimation of the prognosis for patients suffering from sleep bruxism. In addition, it could be also important to adequately evaluate the environmental factors in patients with sleep bruxism.

Gingival Fibroblasts as Autologous Feeders for Induced Pluripotent Stem Cells.

Human gingival fibroblasts (hGFs) present an attractive source of induced pluripotent stem cells (iPSCs), which are expected to be a powerful tool for regenerative dentistry. However, problems to be addressed prior to clinical application include the use of animal-derived feeder cells for cultures. The aim of this study was to establish an autologous hGF-derived iPSC (hGF-iPSC) culture system by evaluating the feeder ability of hGFs. In both serum-containing and serum-free media, hGFs showed higher proliferation than human dermal fibroblasts (hDFs). Three hGF strains were isolated under serum-free conditions, although 2 showed impaired proliferation. When hGF-iPSCs were transferred onto mitomycin C-inactivated hGFs, hDFs, or mouse-derived SNL feeders, hGF and SNL feeders were clearly hGF-iPSC supportive for more than 50 passages, whereas hDF feeders were only able to maintain undifferentiated hGF-iPSC growth for a few passages. After 20 passages on hGF feeders, embryonic stem cell marker expression and CpG methylation at the NANOG and OCT3/4 promoters were similar for hGF-iPSCs cultured on hGF and SNL feeder cells. Long-term cultures of hGF-iPSCs on hGF feeders sustained their normal karyotype and pluripotency. On hGF feeders, hGF-iPSC colonies were surrounded by many colony-derived fibroblast-like cells, and the size of intact colonies at 7 d after passage was significantly larger than that on SNL feeders. Allogeneic hGF strains also maintained hGF-iPSCs for 10 passages. Compared with hDFs, hGFs showed a higher production of laminin-332, laminin α5 chain, and insulin-like growth factor-II, which have been reported to sustain the long-term self-renewal of pluripotent stem cells. These results suggest that hGFs possess an excellent feeder capability and thus can be used as alternatives to conventional mouse-derived SNL and hDF feeders. In addition, our findings suggest that hGF feeders are promising candidates for animal component-free ex vivo expansion of autologous hGF-iPSCs, thus providing an important step toward the future therapeutic application of hGF-iPSCs.

Systematic review and recommendations for nonodontogenic toothache.

Nonodontogenic toothache is a painful condition that occurs in the absence of a clinically evident cause in the teeth or periodontal tissues. The purpose of this review is to improve the accuracy of diagnosis and the quality of dental treatment regarding nonodontogenic toothache. Electronic databases were searched to gather scientific evidence regarding related primary disorders and the management of nonodontogenic toothache. We evaluated the level of available evidence in scientific literature. There are a number of possible causes of nonodontogenic toothache and they should be treated. Nonodontogenic toothache can be categorised into eight groups according to primary disorders as follows: 1) myofascial pain referred to tooth/teeth, 2) neuropathic toothache, 3) idiopathic toothache, 4) neurovascular toothache, 5) sinus pain referred to tooth/teeth, 6) cardiac pain referred to tooth/teeth, 7) psychogenic toothache or toothache of psychosocial origin and 8) toothache caused by various other disorders. We concluded that unnecessary dental treatment should be avoided.

Transcriptional regulation of drug-resistance genes in Candida albicans biofilms in response to antifungals.

Biofilm formation is a major virulence attribute of Candida albicans and is directly associated with therapeutic failure. One method by which Candida acquires antifungal resistance is the expression of drug-resistance genes. This study aimed to evaluate the transcriptional regulation of several genes associated with antifungal resistance of C. albicans under planktonic, recently adhered and biofilm growth modes and in C. albicans biofilms in response to antifungal agents. Initially, the antifungal susceptibility of C. albicans cultures in different growth modes was evaluated by standard antifungal susceptibility testing. Next, to assess CDR1, CDR2, MDR1, ERG11, FKS1 and PIL1 expression, RNA was harvested from cells in each growth mode, and from biofilms after drug treatment, and subjected to quantitative real-time RT-PCR (qRT-PCR). Biofilm C. albicans was more resistant to antifungals than recently adhered cells and stationary-phase planktonic cultures. Transcriptional expression of CDR1, CDR2, MDR1, ERG11 and FKS1 was lower in recently adhered C. albicans than in the stationary-phase planktonic cultures. In contrast, PIL1 levels were significantly increased in recently adhered and biofilm modes of growth. The expression of MDR1 in biofilms greatly increased on challenge with amphotericin B but not with the other drugs tested (P<0.01). ERG11 was significantly upregulated by ketoconazole (P<0.01). Caspofungin and amphotericin B significantly upregulated FKS1 expression, whereas they significantly downregulated PIL1 expression (P<0.01). These results indicate that the expression of drug-resistance genes is associated with higher drug resistance of Candida biofilms, and lay a foundation for future large-scale genome-wide expression analysis.

Mean power frequency during speech in myalgia patients.

The purpose of this study was to clarify a difference of mean power frequency (MPF) during speech between control and myalgia patients groups. The control group consisted of 20 asymptomatic volunteers and the myalgia patients group consisted of 19 patients. A bilateral electromyogram (EMG) of masseter muscles during speech movement was recorded using surface electrodes, and the EMG data were stored and analysed with a computer-based EMG analyzer. The MPF during the entire duration of EMG burst during speech was compared between the control and myalgia group. The average (SD) MPFs during speech in the myalgia and control groups were 214.06 (17.23) and 183.39 (22.35) Hz, respectively, significantly higher in the former (P < 0.001). In myalgia patients, firing rates or recruitment of motor units innervated by high threshold motoneurons might decrease and lead to a higher MPF. The result suggests the possibility that muscle pain, that is a subjective experience, could be evaluated by objective data that is calculated from electromyographic activities which is recorded during speech.

Effect of filamentation and mode of growth on antifungal susceptibility of Candida albicans.

Biofilm formation involving profuse hyphal growth is a major characteristic of Candida spp. and confers higher antifungal resistance than its planktonic mode of growth. We investigated the antifungal susceptibility of Candida albicans and its hyphal mutants (Delta efg1/efg1, Delta cph1/cph1 and DeltaDelta cph1/cph1 efg1/efg1) to commonly used antifungals during planktonic, adhesion and biofilm modes of growth. The minimum inhibitory concentration (MIC) of each antifungal agent was determined for a lower inoculum (1x10(3) cells/mL) and higher inoculum (1x10(7) cells/mL) of planktonic Candida. Furthermore, MICs of C. albicans biofilms and adhesion modes of growth were determined with a standard XTT assay. Candida albicans in adhesion and biofilm modes of growth, but not in planktonic mode, were resistant to all five antifungal agents tested. Although Delta efg1/efg1 and DeltaDelta cph1/cph1 efg1/efg1 mutants formed less biofilm than wild-type C. albicans SC5314, they were similarly resistant to caspofungin. However, these mutants were more sensitive to amphotericin B and nystatin than the wild-type. Adhesion per se confers increased resistance to antifungal agents, which is further pronounced in the biofilm mode of Candida. Filamentation does not appear to be a major determinant of the antifungal resistance in Candida biofilms.

The influence of single molar crown placement on the smoothness of masticatory movement.

The jerk-cost is an index that can quantify the smoothness of various movements including human body movements. A previous study reported the usefulness of jerk-cost in the evaluation of masticatory movement, and proposed that the masticatory movement of subjects with good occlusion could be explained as a maximum smooth movement. The purpose of this study was to investigate the influence of a single prosthetic molar restoration on the smoothness of masticatory movement. Fourteen adults who visited this hospital seeking a single prosthetic restoration on a molar were selected. Each subject chewed a piece of chewing gum on the molars of the treated side before and after crown placement. Movement trajectory was recorded using the Sirognathograph Analyzing System. Normalized jerk-cost (NJC) was calculated on the closing phase of each chewing cycle and was compared before and after the crown placement. After the prosthetic restoration, NJC significantly decreased (P < 0.05) in seven subjects with a crown placed on a lower molar, whereas significant changes were not observed in seven subjects with a crown placed on an upper molar. These results suggest that restoring a crown on a lower molar could significantly improve the smoothness of masticatory movement on the same side.

Occlusal interference during mastication can cause pathological tooth mobility.

BACKGROUND AND OBJECTIVE: Despite little evidence regarding the relationship between tooth mobility and nonworking contact, the evaluation of occlusion is performed mainly by the detection of premature and/or nonworking contacts during tapping movements and lateral excursion. The hypothesis of this study is that occlusal contact during mastication is potentially traumatic to periodontal tissue. It clarifies the relationship between chewing patterns and the status of periodontal tissue. MATERIAL AND METHODS: Subjects included 73 adults, 20-29 years of age (39 men and 34 women), with complete sets of teeth and no history of orthodontic treatment or periodontal disease. The closing chewing patterns of each subject were classified into three groups by the Masticatory Deviation Index, which depicts the deviation from the normal chewing patterns within 5 mm from the intercuspal position. Periotest was used to diagnose teeth mobility and the values were compared among the three groups. RESULTS: The present study indicates that the chewing movements which deviated from the normal chewing movements increased the mobility of specific types of teeth. CONCLUSION: The results of this study imply a relationship between chewing movements and tooth mobility and indicate that functional evaluation of occlusion is necessary for the examination of periodontal tissue. Occlusal evaluation with border and tapping movements might be insufficient, and functional occlusal evaluation during chewing movements can be clinically useful for using to evaluate periodontal tissue.

An in vitro evaluation of the adhesion of Candida species to oral and lung tissue cells.

The analysis of the adherence capacity of fungi to surfaces of both oral tissue and different tissues would be of interest in the fungal dissemination as an oral and systemic pathogen. We developed an in vitro adenosine triphosphate (ATP)-based assay technique to extract the cellular and fungal ATP separately, which allowed the quantitative evaluation of the adhesion of the yeast to monolayers of human gingival epithelial cells (GEC), gingival fibroblasts (GF) and pulmonary fibroblasts (PF). Seven oral isolates of Candida species (three of Candida albicans, three of Candida tropicalis and one of Candida glabrata) were used in the study. The adherent level of the Candida species varied depending on both the isolates and the cell origins, although all the Candida isolates had a significantly higher level of adherence to GEC than to GF except the single isolate of C. tropicalis. Whereas the adherent level of the five isolates to GEC was significantly higher than that to PF, the adherent level of the remaining two isolates of C. tropicalis to GEC was significantly lower than that to PF. These results suggest that candidal adherence to host tissue cells should be regulated in an isolate-dependent and cell-origin-dependent manner, and that the phenomena may be involved in the colonisation and/or dissemination of the fungi.

Self-reported remission, difficulty, and satisfaction with nonsurgical therapy used to treat anterior disc displacement without reduction.

OBJECTIVE: The purpose of this study was to identify the appropriate treatment element for initial anterior disc displacement without reduction subjects. STUDY DESIGN: Sixty-nine consecutive patients with temporomandibular joint disc displacement without reduction confirmed on magnetic resonance images were randomly divided into 3 experimental treatment groups. The treatment of group 1 consisted of short-term nonsteroidal anti-inflammatory drugs and self-care instructions (palliative care group); group 2, nonsteroidal anti-inflammatory drugs, self-care instructions, and occlusal appliance and mobilization therapy (physical medicine group); and group 3, no treatment (control group). Outcomes were assessed by means of a 5-item questionnaire that evaluated (1) symptom improvement, (2) difficulty of treatment, and (3) satisfaction with treatment during the 8-week observation period. RESULTS: Improvement scores in the palliative care group were significantly better than those in the physical medicine group or the no-treatment group. Satisfaction scores showed no significant difference among the 3 groups. Difficulty from treatment for the physical medicine group was significantly greater than that for other 2 groups. CONCLUSION: These data suggest that palliative care would be more appropriate as the initial therapy to treat painful anterior disc displacement without reduction.

A repetitive, steady mouth opening induced an osteoarthritis-like lesion in the rabbit temporomandibular joint.

Although excessive mechanical stress is assumed to be one of the factors contributing to pathogenesis of temporomandibular joint (TMJ) osteoarthritis (OA), no pure mechanical-stress-induced OA model has been developed without surgical manipulation or puncture of the joint cavity. The purpose of this study was to establish a genuine mechanical-stress-induced OA model of the rabbit TMJ. In the experimental rabbits, repetitive, forced jaw-opening, 3 hrs/day for 5 days, was applied with the use of a general anesthesia protocol. By histological assessment of the TMJ articular tissues, partial eburnation of the articular cartilage, reactive marginal proliferation of the articular cartilage chondrocytes, and nested proliferation of chondrocytes in the subchondral bone area were observed at 7 days after the repetitive, forced-jaw-opening period. These results suggest that the repetitive, forced-jaw-opening protocol without surgical intervention can induce evident OA-like lesions in the rabbit TMJ, and this OA model may greatly contribute to the elucidation of the cartilage degradation mechanism in TMJ OA.

Signal intensity changes in T2-weighted MR image of the human trapezius muscle upon cold pressor stimulation.

OBJECTIVE: The ability to measure hemodynamics of skeletal muscle proper is one of the major goals for muscle pain researchers. The aim of the present study was to evaluate the ability of signal intensity (SI) in T2-weighted trapezius muscle magnetic resonance imaging (MRI) to detect intramuscular hemodynamic changes during cold pressor stimulation (CPS). MATERIALS AND METHODS: Fifteen healthy volunteers (mean age, 25.9+/-2.1 years) participated in this study. T2-weighted MRI was acquired using a 1.5 tesla MR unit with a body array coil. The slice level was set perpendicular to the muscle long axis at the mid-point of the horizontal portion of the right trapezius muscle. Cold pressor stimulation (4 degrees C) was applied to each subject's right foot and ankle for 2 min. The SI changes were recorded continuously for 7 min before, 2 min during, and 6 min after withdrawal of cold pressor stimulation. Six of these subjects also underwent a mock-CPS trial. RESULTS: The mean SI level in T2-weighted trapezius muscle MRI significantly increased during CPS (P<0.0001, one way repeated measure ANOVA) and returned to the baseline level after cold pressor withdrawal. No statistically significant signal changes were observed across the mock-CPS trial subjects. These findings are identical to the cold pressor-induced hemodynamic changes documented in the trapezius muscle by near-infrared spectroscopy evaluation. CONCLUSIONS: SI measurement in T2-weighted trapezius muscle MRI is sufficiently sensitive to detect intramuscular hemodynamic changes during CPS.

Regulatory mechanism of human connective tissue growth factor (CTGF/Hcs24) gene expression in a human chondrocytic cell line, HCS-2/8.

CTGF/Hcs24 is a multi-functional growth factor that potentiates either the growth or differentiation of mesenchymal cells, according to the biological conditions. Among various functional aspects of CTGF/Hcs24, it is especially notable that CTGF/Hcs24 may promote endochondral ossification in growth cartilage through all stages, and it is highly expressed in a human chondrosarcoma-derived chondrocytic cell line (HCS-2/8). In this study, to clarify the regulatory mechanism of CTGF/Hcs24 gene expression in chondrocytes, we analyzed the transcriptional activity of the CTGF/Hcs24 promoter and the effect of the CTGF/Hcs24 3'-untranslated region (3'-UTR) on gene expression in HCS-2/8 by means of an established DNA transfection and luciferase reporter gene assay system. As a result, the luciferase activity of the CTGF/Hcs24 promoter was found to be remarkably high in HCS-2/8. The 3'-UTR of the CTGF/Hcs24 gene strongly repressed the luciferase activity in HCS-2/8, when it was linked to the downstream of the luciferase reporter gene, suggesting its functionality also in chondrocytic cells. Deletion analysis of the CTGF/Hcs24 promoter clarified a major segment responsible for the enhanced CTGF/Hcs24 promoter activity in HCS-2/8. The TGF-beta response element in the DNA segment was active in HCS-2/8, and point mutations in the element moderately decreased the highly maintained promoter activity with total loss of TGF-beta responsiveness. These results indicate that the strong expression of the CTGF/Hcs24 gene in HCS-2/8 was mainly caused by high transcriptional activity of the CTGF/Hcs24 promoter, and that the TGF-beta response element is one of the critical elements that support the high transcription activity.

Correlation of the near-infrared spectroscopy signals with signal intensity in T(2)-weighted magnetic resonance imaging of the human masseter muscle.

The purpose of this study was to compare and contrast blood volume changes transcutaneously measured using near-infrared (NIR) spectroscopy against water signal intensity changes taken from a transverse T(2)-weighted MR image of the masseter muscle in healthy human subjects before, during and after contraction. Eight healthy non-smoking males with no history of chronic muscle pain or vascular headaches participated (mean age: 23.9+/-0.6 years). The MRI data were gathered using a turbo spin echo sequence (TR: 2300 ms; TE: 90 ms; FOV: 188x300 mm; scanning time: 30 s; slice thickness: 10 mm) and the slice level was set at the mid-point between the origin and insertion of the masseter. Intramuscular haemoglobin (Hb) levels and water content of the right masseter muscle were continuously monitored for 2 min before, 30 s during and 15 min after a maximum voluntary clenching (MVC) task. Both the near-infrared and MRI data were baseline-corrected and normalized and mean levels were established and plotted. Plots of the data showed that both near-infrared-based total Hb and T(2)-weighted MRI-based signal-intensity levels clearly decreased during contraction and a clear post-contraction rebound response was evident after the contraction. The near-infrared data were found to be highly correlated with MRI-based signal-intensity data (Pearson's r=0.909, P<0.0001). In conclusion, these data provide powerful evidence that near-infrared data (total Hb), transcutaneously taken from the masseter muscle in humans, will reflect the intramuscular water signal intensity changes seen using a T(2)-weighted MRI imaging method.

Randomized controlled evaluation of non-surgical treatments for temporomandibular joint anterior disk displacement without reduction.

The common methods for treating anterior disk displacement without reduction (ADDwor) are not based on randomized controlled clinical trials. Our study evaluated non-surgical treatments in 69 MRI-confirmed ADDwor subjects (m/f = 6/63). Subjects were randomly assigned to a control group and one of two treatment groups. Outcomes included maximum mouth opening, visual analogue scale of pain, and daily activity limitation. Calibrated examiners collected data at the initial interview and at 0, 2, 4, and 8 weeks of treatment. At the eight-week point, within-group improvements were present for all variables, for all groups. Between-group differences were not highly evident, with only mean daily activity limitation for the self-care/NSAID group being significantly lower than that of the occlusal appliance/jaw mobilization + self-care/NSAID group at the two- and four-week time-points. These results suggest that ADDwor subjects will improve with only minimal treatment intervention, and no significant difference was evident for the treatments tested and the control condition.

Intramuscular haemodynamic responses to different durations of sustained extension in normal human masseter.

Ten healthy non-smoking males (mean age 24.3+/-0.8 years) with no history of chronic muscle pain or migraine participated in this study. Intramuscular total haemoglobin (Hb), an indicator of blood volume in the illuminated area, was measured with a non-invasive, near-infrared spectroscopic device. Each participant was told to maintain maximal mouth opening to extend the masseter muscle for 30, 60 or 120 s in random order. Data were continuously recorded from the right masseter 1 min before, at set times during and for 5 min after sustained muscle extension in each trial. Each trial was separated by a 10-min interval. Heart rate (HR) and blood pressure (BP) were also recorded. The mean normalized Hb decreased during muscle extension and rebound hyperaemia was observed after it in each trial (P=0.0001). Hb returned to baseline within 60 s. The magnitude of the decremental change during extension and of the incremental change in the rebound hyperaemia was not significantly different among the three trials (P=0.9071); neither were mean normalized HR and BP. These data suggest that sustained extension of the masseter produces a reduction in total intramuscular Hb during extension and a secondary increase in Hb following a return to the resting muscle's normal length.

Pilot study of conditioner/primer effects on resin-dentin bonding after provisional cement contamination using SEM, energy dispersive x-ray spectroscopy, and bond strength evaluation measures.

STATEMENT OF PROBLEM: Previous studies have shown that provisional cement cannot be completely removed from the dentin surface and the remnants inhibit adhesion of resin cement to dentin. PURPOSE: This study investigated the effects of dentin conditioners on resin-dentin bonding after provisional cement contamination. MATERIAL AND METHODS: A total of 216 bovine dentin specimens were divided into 2 groups with and without provisional cement coating on the dentin surface. Each group was further divided into 3 subgroups with 2 conditioning methods and without dentin conditioning (36 specimens per subgroup). The 2 methods applied were (1) phosphoric acid etching and (2) phosphoric acid etching, followed by sodium hypochlorite gel. Provisional cement was completely removed with a curette before dentin conditioning. Stainless steel rods were luted to dentin surfaces with Panavia 21 resin cement. Tensile bond strengths were measured before and after thermocycling. The dentin surface was analyzed by SEM and energy dispersive x-ray spectroscopy. Three-way ANOVA and Scheffe's comparison test were performed (P =. 05). RESULTS: Bond strength was significantly influenced by provisional cement application, type of dentin conditioning, and thermocycling. Bond strength decreased when treated with provisional cement, but the decreased strengths were restored to their original values or higher by both dentin conditioners used. Specimens treated with sodium hypochlorite gel applied after phosphoric acid etching demonstrated the highest bond strengths with good stability after thermocycling. CONCLUSION: Application of sodium hypochlorite gel after phosphoric acid etching was more effective than etching with phosphoric acid alone to eliminate the inhibitory effect of provisional cement remnants on adhesion between resin cement and dentin.