Influence of different denture adhesives on patient-based outcomes: A crossover randomized controlled trial.

STATEMENT OF PROBLEM: The influence of different denture adhesive forms on retention, stability, denture movement, and masticatory efficiency have been studied. However, studies that investigated their effect on patient-based outcomes are scarce. PURPOSE: The purpose of this crossover randomized controlled trial was to investigate the influence of 3 different denture adhesive forms on patient satisfaction and oral health-related quality of life (OHRQoL) in edentulous individuals. MATERIAL AND METHODS: A total of 30 edentulous participants were enrolled. They initially received conventional dentures, which they used for 3 months. They were then instructed to use 3 forms of denture adhesives (cushion, paste, and powder) for 3 months each. Patient satisfaction was assessed by using a visual analog scale (VAS), and OHRQoL was assessed by using the oral health impact profile in the edentulous adults instrument. Assessments were done 3 months after wearing the conventional dentures, then after by using each denture adhesive form for 3 months, with a 1-month washout period. The average retention duration for each form and participant preference were also evaluated. Statistical analysis was conducted by using the repeated measures ANOVA test followed by the Scheffé test for VAS scores and retention duration. The Friedman test followed by the Wilcoxon signed-rank test was used for OHRQoL scores (α=.05). RESULTS: Irrespective of their forms, denture adhesives significantly improved patient satisfaction in most aspects (P<.001) and significantly improved OHRQoL (P<.001). VAS scores for the cushion form were significantly higher than those for the other 2 forms regarding general satisfaction, comfort, and ease of cleaning dentures and tissues. For stability and masticatory ability, the cushion and paste forms were significantly better (P<.05) than the powder form. OHRQoL scores were significantly higher (worse) for the powder form compared with the other 2 forms for the functional limitation, physical pain, and physical disability domains, with insignificant differences between the cushion and paste forms (P>.05). The powder form found the shortest retention duration and the least preference. CONCLUSIONS: Denture adhesives significantly improved OHRQoL and almost all aspects of patient satisfaction. The cushion form provided higher satisfaction levels for most aspects, followed by paste and then powder. OHRQoL outcomes were comparable for all forms, except for the functional limitation, physical pain, and physical disability domains, which were significantly better with the cushion and paste forms. The cushion and paste forms were more retentive and more preferred by the participants than the powder form.

Effect of non-rigid connector on the stress distribution of tooth-implant supported fixed prostheses using different implant length and diameter: A comparative 3D finite element study.

PURPOSE: To investigate the significance of the connector type on stress dissemination within the tooth-implant-supported fixed dental prostheses in the mandibular posterior region with different combinations of implant diameter and length by means of finite element analysis (FEA). MATERIALS AND METHODS: Six models of different designs for tooth-implant fixed dental prosthesis (FDPs) were simulated and divided into two main groups. Implant lengths were 10, 11.5, and 13 mm while implant diameters were 3.7, 4.7, and 5.7 mm. The main difference between the groups was the connector type. Models were evaluated using 3D FEA (Solidworks Premium 2018 × 64 Edition). Group A tooth-implant FDPs (5.7 mm × 10 mm) had a mesial and distal rigid connector while group B tooth-implant FDPs (3.7 mm × 10 mm, 3.7 mm × 11.5 mm, 3.7 mm × 13 mm, 4.7 mm × 10 mm and 5.7 mm × 10 mm) had a mesial non-rigid connector in their design between the pontic and the tooth. Models were analyzed to determine the magnitude of von Misses Stresses at six specific zones (fixed dental prosthesis, bone around distal implant, bone around tooth, cementum, periodontal ligament, implant) under vertical occlusal loading of 100 N after meshing and assigning the material properties. RESULTS: Stress values around the supporting bone were significantly higher in Group B (tooth-implant FDP with non-rigid connection) when compared to Group A (tooth-implant FDP with rigid connection). Also, the stresses measured at the FDP level showed that the rigid connection group (5.7 mm × 10 mm) exhibited 26% lower stress values when compared to the non-rigid group (5.7 mm × 10 mm). CONCLUSIONS: Implant-tooth FDPs with rigid connector design using the combination of implant diameter and length (5.7 mm × 10 mm) demonstrated a better design modality thus predicting a higher success rate and more longevity than using the non-rigid connection option.

Knowledge of Saudi dental students and interns towards luting cements and their applications in fixed prosthodontics.

BACKGROUND: Enhancement of students' knowledge is essential in improving their clinical skills and performance. Thus, the curriculum should be prepared to achieve a better outcome. The current study aimed to determine the dental students' and interns' basic knowledge towards dental luting cements and their application in dental practice to improve the theoretical and clinical training sections. MATERIALS AND METHODS: A cross-sectional study was conducted among dental students and interns at three Colleges of Dentistry in the Kingdom of Saudi Arabia between September 2019-June 2020. An online questionnaire was used which included demographic data, questions about luting cement usage, cementation techniques, and commonly used cements in dental clinics. Descriptive analysis and chi-square test were used to show the association between level of dental education and the use of dental cements using SPSS software. The significance level was set at 5%. RESULTS: The total respondents were 626 dental students/interns of whom 78.8% were undergraduate dental students. Participants who reported undergraduate studies as the source of information were 79.7%. The type of restoration was the main factor in luting cement selection (62.6%). Concerning the isolation technique in cementing laminate veneers, 49.7% used dri-angles, cotton rolls and saliva ejectors. Dual-cure resin cement was the most common cement used in all the mentioned restorations except in pressed porcelain laminate veneers and cement-retained implant-supported restorations. CONCLUSIONS: Students' knowledge and practice in managing dental implants and porcelain laminate veneers need to be improved. The selection of a luting agent for a given restoration by students and interns was based on the basic knowledge, available cement, and the type of restoration. Awareness towards the management of short prepared teeth and custom-made cast posts and cores is also limited.

Transmission of radiant light energy through the sides of fiber posts.

OBJECTIVES: Resin cements are light polymerized, but the light may not reach all areas of root canals. The purpose of this study was to determine the best predictor of transmitted light radiant exposure (TLRE) from posts' sides. MATERIALS AND METHODS: Fiber posts were placed in a custom-made apparatus and advanced by 1-mm increments. The LED curing probe tip was activated for 40 s on the coronal end of the post. The TLRE was measured with an LED radiometer detector positioned on the side of the post exposed by an opening in the apparatus. Hierarchical multiple linear regression analysis was performed. RESULTS: Post system explained an additional 23.62% of the variation in TRLE. Adding actual post diameter explained an additional 62.64% of the variation in TRLE. While adding post length explained an additional 0.67%. Changing post system from FiberKleer to Postec Plus will decrease the mean value of TRLE by 4.90 units on average. Also, a one-unit increase of actual post diameter and length will decrease the value of TRLE by 44.96 and 0.44 units respectively. The TLRE ranged from 46 to 290 mJ/cm2 , which was between 0.73% and 6.63% of the original emanating light. CONCLUSIONS: The changes in post system, posts' diameter and length can be used to predict the unit changes in TLRE on the side of a translucent fiber post. Emanating radiant exposure from the side of the post was lower than 6.63% of the exposure entering the post. CLINICAL RELEVANCE: Fiber post diameter and length and post system can influence light radiant exposure transmitted from posts' sides, transmitting minimal radiant exposure, which can be increased by increasing curing duration.

Novel CAD-CAM zirconia coping design to enhance the aesthetics and strength for anterior PLZ crowns.

BACKGROUND: The aesthetics and strength of anterior porcelain layered zirconia (PLZ) crowns are mainly affected by the zirconia (Zr) coping design. There is a need for a modified design to enhance aesthetics with strength. OBJECTIVES: The purpose of this study was to compare the fracture resistance of anterior PLZ crowns having modified CAD-CAM Zr coping designs (in terms of thickness and marginal collar designs) with standard Zr copings. METHODS: Fifty PLZ crowns were fabricated and divided into two groups: Gr 1: Standard Zr Coping (SZC) (control gr) with 0.5 mm thickness (Facial-F, Mesial-M, Distal-D, incisal-I, and Palatal-P) without a collar; Gr 2: Collar Zr Coping (CZC) (test gr) with 2.5 mm collar height on M, D, P and 0.2 mm F and variable facial wall thickness. Subgroups: Gr 2a: (CZC-0.5 mm) facial wall thickness 0.5 mm; Gr 2b: (CZC-0.4 mm) facial wall thickness 0.4 mm; Gr 2c: (CZC-0.3 mm) facial wall thickness 0.3 mm; Gr 2d: (CZC-0.2 mm) facial wall thickness 0.2 mm. The fracture load was determined and analysed using One-way ANOVA and Dunnet test. RESULTS: The minimum fracture load was 927.36 ± 127.80 N observed for Gr 2c (CZC at 0.3 mm) while the maximum fracture load was 1373.61 ± 146.54 N observed for Gr 2a (CZC at 0.5 mm). A highly significant difference in mean fracture load among various Zr coping groups (p< 0.001) was determined. CONCLUSIONS: Novel Zr coping design for anterior PLZ crowns can provide better aesthetics with strength. Reducing the thickness of Zr coping in the aesthetic zone to 0.2 mm and providing a modified collar design (2.5 mm collar height on M, D, P, and 0.2 mm F) would provide strength without jeopardizing aesthetics.

Synergistic effect of graphene oxide/calcium phosphate nanofiller in a dentin adhesive on its dentin bond integrity and degree of conversion. A scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared, micro-Raman, and bond strength study.

The objective was to formulate and analyze a dentin adhesive incorporated with graphene oxide (GO) nanoparticle and calcium phosphate (CaP) composite. Methods comprising of scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy, shear bond strength (SBS), and Fourier transform infrared (FTIR) spectroscopy were used to characterize nanoparticle composite, dentin bond toughness, degree of conversion (DC), and adhesive-dentin interaction. Postsynthesis of GO nanoparticles, they were functionalized with CaP using standard process. The GO-CaP composite was not added to experimental adhesive (negative control group, GO-CaP-0%), and added at 2.5 and 5 wt% to yield GO-CaP-2.5% and GO-CaP 5% groups, respectively. Teeth were set to form bonded samples utilizing adhesives in three groups for SBS testing, with and without thermocycling. The homogenous diffusion of GO-CaP composite was verified in the adhesive. Resin tags having standard penetrations were observed on SEM micrographs. The EDX analysis confirmed the occurrence of calcium, phosphorus, and carbon ions in the composite containing adhesives. The SBS test revealed highest mean values for GO-CaP-5% followed by GO-CaP-2.5%. The FTIR spectra verified the presence of apatite peaks and the micro-Raman spectra showed characteristic D and G bands for GO nanoparticles. GO-CaP composite in dentin adhesive may improve its bond strength. The addition of 5 wt% resulted in a bond strength that was superior to all other groups. GO-CaP-5% group demonstrated lower DC (to control), uniform distribution of GO and CaP composite within adhesive, appropriate dentin interaction, and resin tag formation.

Influence of abutment material on the shade of dental implant restorations in the esthetic zone: a single case report.

High esthetic demand and expectation challenges the rehabilitation of the esthetic zone with dental implants. Most implant system manufacturers offer customized and prefabricated ceramic, specifically zirconia or alumina abutments, as an alternative to titanium or gold alloy abutments, with the aid of computer-aided designing/computer aided manufacturing (CAD/CAM) technology. A 45-year-old male patient was referred to the prosthodontics clinic for the restoration of maxillary central incisors with all ceramic dental implants. After healing, both implants were restored with all-ceramic crowns but different customized abutment materials for the purpose of comparison. The all-ceramic crown was cemented on a customized zirconia abutment at the implant site # 11 and on a customized gold alloy abutment at implant site # 21. The treating dentist as well as two prosthodontists performed a meticulous clinical examination to compare the ceramic crowns side by side and agreed that the outcome was esthetically satisfactory. The patient was satisfied with the esthetics and functional outcome of the final restorations, as was the prosthodontist.

Effect of Er,Cr:YSGG on bond strength and microleakage of dentin bonded to resin composite with different distance and irradiation time.

BACKGROUND: To explore the surface modification of dentin using Er,Cr:YSGG phototherapy and bonding system on the shear bond strength and microleakage scores at two different distances and times of laser irradiation. MATERIALS AND METHODS: Ninety disease-free third molars were collected for the experiment. The four laser groups were divided on the basis of non-contact mode distance and time of irradiation: Group-I: Distance of 1 mm with duration of 60 s; Group-II: Distance of 1 mm with duration of 120 s; Group-III: Distance of 2 mm with duration of 60 s and; Group-IV: Distance of 2 mm with duration of 120 s. The surface for control group (Group-EB: Etch & bond group) was treated with etch and rinse bonding regime. Specimens from all the groups were assessed for shear bond strength and microleakage scores. Samples from all groups were immersed in 2% methylene blue for 24 h and assessed under a digital microscope for microleakage. RESULTS: The lowest bond strength and microleakage was observed in the control group EB. The maximum bond strength score was observed in Group-IV with mean scores 23.41 ± 1.83, while the maximum microleakage scores were observed in Group-II and Group-IV with mean scores 1.0 ± 0.36 and 1.0 ± 0.11, respectively. The lowest bond strength and microleakage among laser groups was observed in Group-II and Group-III, respectively. However, specimens in laser groups showed comparable bond strength and microleakge scores (p > 0.05). For bond strength and microleakage values, analysis of variance showed significant difference among the study groups (p < 0.001). Using Tukey post hoc test, bond strength and microleakage of laser groups showed statistically significant values than EB group. CONCLUSION: Use of phototherapy using Er,Cr:YSGG for dentin surface treatment has the potential for clinical application in comparison to conventional conditioning technique. Increasing the distance of laser application and time of irradiation has significant effect on the shear bond strength and microleakage scores of dentin bonded to resin composite. However, further in-vitro analysis should be undertaken in order to prove such findings.

Clinical indices and local levels of inflammatory biomarkers in per-implant health of obese and nonobese individuals.

BACKGROUND: Obesity seem to regulate peri-implant health. It is proposed that peri-implant crevicular fluid (PICF) levels of interleukin (IL)-1ß and IL-6 are higher in obese as compared to nonobese individuals. OBJECTIVE: The purpose of the present clinico-laboratory study is to estimate and compare the clinical and radiographic indices and PICF levels of IL-1ß and IL-6 among obese and nonobese patients. MATERIALS AND METHODS: Fifty patients were divided into two groups (25 obese with ≥27.5 kg/m2 and 25 nonobese with <27.5 kg/m2 individuals). Clinical indices for both periodontal and peri-implant evaluating plaque index (PI), bleeding on probing (BOP), probing depth (PD), clinical attachment level (CAL), and crestal bone loss (CBL) were recorded around teeth and implants. PICF was collected and assessed for the levels of IL-1ß and IL-6 using enzyme-linked immunosorbent assay. RESULTS: A significant difference was observed in PI and BOP around natural teeth and implants in obese patients, respectively (P < .05). CBL was found to be significantly higher among obese as compared to nonobese patients (P = .022). Peri-implant and periodontal PD was higher in obese as compared to nonobese but did not reach statistical significance. Levels of IL-1ß and IL-6 were statistically significantly higher among obese patients as compared to nonobese (P = .001). Pearson correlation analysis showed IL-1ß was positively correlated with CBL (P = .0079), whereas IL-6 showed positive correlation with both BOP (P = .0019) and CBL (P = .015) among obese patients. CONCLUSIONS: Clinical peri-implant parameters were worse and proinflammatory biomarkers were significantly higher in obese patients compared with nonobese subjects. The findings of the present study suggests that increased proinflammatory biomarkers in PICF of obese patients may modulate peri-implant inflammation around dental implants.

Effects of using Antifungal Gel on Retentive Bond Strength of Two Forms of Denture Adhesives: An in vitro Study.

AIM: The purpose of this in vitro study is to compare the bond strength to denture acrylics efficacy of miconazole gel against two denture adhesives with improved retentive properties (zinc-free PoliGrip cream and Snug denture soft cushion). MATERIALS AND METHODS: Eight heat-cured acrylic samples were prepared measuring 0.7 cm × 1.4 cm flat tested surface. The two well-adapted tested surfaces were matched and fixed to Universal Testing Machine clamp. Vertical separating load was applied at a rate of 1 mm/min to yield the maximum load before denture adhesive failure occurs. These measurements were used to express the retention bond strength when improved denture adhesive material was applied alone in comparison with micon-azole nitrate gel. Results were analyzed using one-way analysis of variance (ANOVA) statistical analysis at p-value of < 0.05. RESULTS: There was a statistically significant reduction in the mean tensile strength when the antifungal gel was opposed by the zinc-free PoliGrip cream. However, such a significant difference was not evident when the Snug denture cushion was opposed by the miconazole gel. CONCLUSION: The addition of antifungal gel to denture adhesives reduces retentive bond strength of denture adhesives to denture acrylics. However, if an antifungal gel has to be used, then a denture adhesive cushion soft plastic liner may provide a better retentive option than denture adhesive cream. CLINICAL SIGNIFICANCE: The incorporation of an antifungal agent into denture adhesives is required in many denture patients to suppress fugal growth and eliminate the undesirable health effects associated with such infections.

Effect of Surface Treatments and Adhesive Materials on the Shear Bond Strength of Artificial Denture Teeth to Denture Base Resins.

AIM: The purpose of the current study was intended to evaluate the effect of different surface modifications and different adhesive materials on the shear bond strength of artificial teeth to heat-polymerized and thermoplastic denture base materials using different repair techniques. MATERIALS AND METHODS: Forty cross-linked artificial teeth used to construct different types of acrylic based denture prosthesis were selected to be bonded to two types of denture base materials, heat-polymerized acrylic resin denture base material, and thermoplastic acrylic resin denture base material. The specimens were divided into four subgroups according to the repair technique and adhesive material used. The base surfaces of all acrylic teeth then were moistened with monomer prior to bonding to the denture base specimens. Then, the specimens were tested using Universal Testing Machine for shear bond strength. The results were analyzed by using two-way analysis of variance (ANOVA) statistical analysis and multiple comparison tests, α ≤ 0.05. RESULTS: The effect of the types of denture base materials vs the surface conditioning methods displayed a statistically significant difference. CONCLUSION: This study concluded that monomer surface treatment of the bonded surface of artificial denture teeth and the use of cyanoacrylate adhesive followed by additional microwave polymerization displayed better shear bond strength when compared with other repair techniques. CLINICAL SIGNIFICANCE: Artificial teeth debonding from their denture bases is a common complication in dental practice. The current study evaluates different repairing techniques. Within the limitation of this study, the use of cyanoacrylate adhesive in combination with microwave polymerization is one of the best techniques of repairing denture teeth debonding.

Effectiveness of adjunctive antimicrobial photodynamic therapy in reducing peri-implant inflammatory response in individuals vaping electronic cigarettes: A randomized controlled clinical trial.

BACKGROUND: There are no studies that have assessed the effectiveness of antimicrobial photodynamic therapy (aPDT) in reducing peri-implant inflammatory response in individuals vaping electronic cigarettes (e-cigs). This study explored the effectiveness of aPDT as an adjunct to mechanical debridement (MD) in the treatment of peri-implant mucositis (p-iM) in individuals vaping e-cigs. METHODS: Vaping individuals with p-iM were divided into 2 groups: (a) Group-I: receiving MD with aPDT (test group); and (b) Group-II: MD only (control group). Peri-implant inflammatory parameters including plaque index (PI), bleeding on probing (BoP), and pocket depth (PD) were assessed at baseline and 12-weeks follow-up. Inter- and intra-group comparisons were made using Mann-Whitney U test and Wilcoxon signed ranks test. P-value < 0.05 was considered significant. RESULTS: Thirty-eight male patients (20 in Group-I and 18 in Group-II) were included. The mean age of vaping individuals in groups I and II were 33.6 ±â€¯2.8 and 35.4 ±â€¯2.1 years, respectively. Mean daily frequency of vaping e-cigs in groups I and II was 7.3 ±â€¯0.9 and 5.9 ±â€¯1.0 whereas mean duration of vaping e-cigs was 4.8 ±â€¯1.5 and 4.1 ±â€¯1.3 years respectively. There was no significant difference between groups at baseline. There was significant improvement in PI (p < 0.001) and PD (p < 0.001) at 12-weeks follow-up with respect to the baseline visit in both groups. There was a significant reduction in PI (p < 0.001) and PD (p < 0.001) for group-I as compared to group-II at follow-up. There was no statistically significant difference for BoP between groups at follow-up. CONCLUSION: Antimicrobial PDT is more effective compared to MD alone in the treatment of p-iM in individuals vaping e-cigs. The findings of the present study should be considered preliminary and interpreted with caution. Further randomized clinical trials should be performed in order to obtain strong conclusions.

Assessment of matrix metalloproteinase-8 and -9 levels in the peri-implant sulcular fluid among waterpipe (narghile) smokers and never-smokers with peri-implantitis.

OBJECTIVES: It is hypothesized that levels of matrix metalloproteinase (MMP)-8 and MMP-9 are significantly higher in the peri-implant sulcular fluid (PISF) of waterpipe-smokers (WS) compared with never-smokers with peri-implantitis. The aim of the present convenience sample case-control study was to compare the levels of MMP-8 and MMP-9 in the PISF of WS and never-smokers with peri-implantitis. MATERIAL AND METHODS: Individuals smoking waterpipe (Group 1) and never-smokers (Group 2) were included. Demographic data was collected using a questionnaire. Peri-implant probing depth (PPD) was measured and crestal bone loss (CBL) was measured on digital bitewing radiographs. PISF samples were collected using paper strips and the collected PISF volume was determined. Levels of MMP-8 and MMP-9 were measured using enzyme-linked immunosorbent assay. Study sample-size was estimated and statistical analysis was performed. p values < .05 were considered statistically significant. RESULTS: Sixty-six individuals (33 individuals in Group 1 and 33 in Group 2) were included. In Groups 1 and 2, 41 and 44 implants, respectively were placed. The mean total PPD (p < .001) and peri-implant CBL (p < .001) was statistically significantly higher around implants affected by peri-implantitis in Group 1 compared with Group 2. The PISF volume (p < .05) collected and levels of MMP-8 (p < .01) and MMP-9 (p < .01) were statistically significantly higher among individuals in Group 1 compared with Group 2. CONCLUSION: PISF levels of MMP-8 and MMP-9 are significantly higher among WS compared with never-smokers with peri-implantitis.

Arabic Coffee as a Potential Alternative to Black Coffee in the Post- Bleaching Period: An in-vitro Study

Objective: To investigate the effect of Arabic coffee on bleached teeth in comparison to black coffee. Material and Methods: Forty teeth (sound maxillary or mandibular premolars with no carious lesions) were randomly selected into 4 groups (A, B, C and D). One group (A) did not receive bleaching and was incubated in saline. The second group (B) was bleached and then incubated in saline. The last two groups were bleached and were immersed in either Arabic coffee (C) or black coffee (D). Color recording of the samples was always carried out as near to their mid-buccal surfaces as possible using VITA Easyshade Advance System. Color measurements were carried out using a digital spectrophotometer at baseline and after short-term and long-term immersion. Data were subjected to two way ANOVA and T-test. The level of significance was set at was set at 0.05. Results: Results show that immersion in Arabic coffee resulted only in significant reduction in the b* color value upon long-term immersion (i.e. a reduction in the yellow hue). Black coffee on the other hand resulted in significant: reduction in lightness, increased red tint and increased yellow hue altogether. Conclusion: The use of Arabic coffee did not deteriorate color, with the only significant change being the reduction of yellowish hue. Arabic coffee could be an alternative to black coffee after bleaching.

Degree of conversion of resin cement with varying methacrylate compositions used to cement fiber dowels: A Raman spectroscopy study.

STATEMENT OF PROBLEM: Studies on the degree of conversion of dental cement in relation to the number of methacrylate components are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the degree of conversion of single- and multicomponent methacrylate-containing dental cements around opaque and translucent fiber dowels at varying depths. MATERIAL AND METHODS: Teeth were prepared for standard endodontic therapy, and a dowel space was created. Opaque and translucent fiber dowels consisting of Aestheti-Plus (AP) and FiberKleer were cemented with 4 methacrylate (MA)-containing cements, including RelyX U100 (R), which contains TEGDMA; Duolink (D), which contains TEGDMA and BisGMA; and Variolink N LC (V) and Breeze (B), which contain TEGDMA, BisGMA, and UDMA. Light-emitting diode polymerization was performed for 60 seconds. The specimens were immediately cut into halves and measured within the first hour at depths of 1, 3, and 5 mm using Raman spectroscopy, and the degree of conversion (DC) of resin cement was calculated. Data were analyzed using 3-way ANOVA and the Tukey multiple comparison test (α=.05). RESULTS: The measured dowel regions were not significantly different at various depths (P=.10). The dowel and cement types significantly influenced the degree of conversion of the cement (P<.05). The V and B cements exhibited a higher DC than D and R cements. With AP dowels, the DC of cement D was lower than that of the V, B, and R cements. CONCLUSIONS: Within the limitations of this in vitro study, the degrees of conversion of the tested resin cements were not affected by the tested dowel depths. Higher DC was found in cement with more than 2 types of flexible MA. Opaque dowels produced a lower DC than translucent dowels.