International Journal of Dentistry最新文献

This study aimed to evaluate the fracture resistance of teeth with simulated internal root resorption cavities filled with calcium silicate-based cements (CSCs). Seventy-two extracted central incisor teeth had their crowns removed to standardize the root length to 14 mm. The teeth were randomized into six groups (n = 12 each), including a positive control (with no simulated resorption cavities) and negative control (with no filling) group. To simulate internal root resorption cavities, cavities were made along the 6 mm section using a number 10 round bur on groups. In four groups, artificially created resorption areas were filled with ProRoot MTA, Biodentine, NeoMTA 2, and BioMTA+. The specimens were subjected to fracture resistance testing using a universal testing machine (UTC). Compressive 135° angle loading was applied to the roots at a rate of 1 mm/min. The fracture resistance was recorded in Newtons and statistically analyzed using a one-way analysis of variance (Welch's test) and Tamhane's T2 test. The fracture resistance was significantly higher in the Biodentine group than in the negative control group. Therefore, the use of Biodentine in internal root resorption cavities may, to some extent, contribute to preserving or supporting the tooth structure.

Background and objective: Black discoloration is a major challenge encountered when using silver diamine fluoride (SDF) to manage early childhood caries (ECC). This study aimed to assess the carious primary dentin microhardness following the application of sodium fluoride (NaF) varnish with the intensive technique versus fluoride therapy with SDF.

Materials and methods: In this in vitro study, 45 extracted relatively sound primary molars were randomly assigned to three groups: Group 1: Application of 30% SDF, Group 2: Application of Aria Dent varnish (5% NaF) three times within 10 days, and Group 3: Application of MI varnish (5% NaF + casein-phosphopeptide amorphous calcium phosphate [CPP-ACP]) three times within 10 days. After sectioning and dentin surface preparation, dentin microhardness was measured at four different time points: baseline, after demineralization, and 24 h and 45 days after the application of the respective fluoride product. The teeth were under pH-cycling throughout the entire study period. The microhardness values were compared among the groups, and at different time points using the generalized estimating equations (GEEs) model.

Results: The mean microhardness at 24 h after treatment was not significantly different from that after demineralization in any group (p > 0.05). The mean microhardness significantly decreased in the 30% SDF group and significantly increased in the two NaF varnish groups at 45 days compared to 24 h (p  < 0.05). The pattern of change in microhardness was significantly different among the three groups (p  < 0.0001). MI varnish increased the microhardness significantly more than the other products within the 45-day study period (p  < 0.05).

Conclusions: The intensive protocol of NaF varnish application three times within 10 days, especially MI varnish that contains CPP-ACP, may enhance the microhardness significantly more than SDF in the first month of use. This protocol may be able to serve as an efficient alternative to SDF.

Objectives: This study evaluated the association between key prognostic factors in nonsurgical endodontic treatment and the presence and size of periapical lesions (PALs) in mandibular anterior and premolar teeth using cone-beam computed tomography (CBCT).

Materials and methods: A cross-sectional analysis was conducted on 63 CBCT scans covering 105 mandibular anterior and premolar teeth. Variables examined included missed canals, underfilled or overfilled canals, procedural errors (e.g., perforations and fractured instruments), intracanal posts (cast or prefabricated), and restoration type. The presence and volume of PALs were assessed, and associations were evaluated using a general linear model (GLM) and multiple logistic regression (α = 0.05).

Results: Among 63 patients (27 males and 36 females), PALs were observed in 43 teeth (41%) with an average lesion volume of 7.90 mm³. No significant association was found between PAL occurrence and age, gender, tooth type, restoration type, or intracanal posts (p  > 0.05). However, missed canals (p = 0.042), underfilled (p  < 0.001), overfilled canals (p  < 0.001), perforations (p = 0.020), and fractured instruments (p = 0.033) were significantly associated with PAL presence. Lesion size correlated significantly with gender (p = 0.047), overfilling (p = 0.013), fractured instruments (p  < 0.001), and apical perforations (p = 0.009).

Conclusions: The findings underscore the clinical relevance of missed canals, over- and underfilling, and procedural mishaps in the development and size of PALs. Patient gender also appeared to influence lesion size. These results highlight the need for precision in endodontic procedures to improve periapical healing.

Objective: This study aimed to assess the shear bond strength (SBS) between cobalt-chromium (Co-Cr) alloy and acrylic resin teeth using various surface conditioning methods and to investigate the failure modes associated with these methods.

Materials and methods: A total of 53 Co-Cr specimens were fabricated and randomly assigned to five groups (n = 10 per group) based on the type of surface treatment: (1) polymethyl methacrylate (PMMA; control group), (2) Clearfil Ceramic Primer Plus + PMMA, (3) M&C Primer + PMMA, (4) Super-Bond Universal, and (5) M&C Primer + Super-Bond Universal. Each specimen was subsequently bonded to an acrylic resin tooth. Three specimens from both the control and primer-treated groups were reserved for scanning electron microscopy (SEM) analysis. All samples were stored in distilled water at 37 ± 1°C for 24 h before SBS evaluation with a universal testing machine.

Statistical analysis: Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by Tukey's HSD post hoc test.

Results: A statistically significant difference in bond strength was observed among the experimental groups (p < 0.05), with the Super-Bond Universal group exhibiting the highest bond strength (8.01 ± 1.05 megapascals [MPa]), compared to the control group (3.07 ± 0.48 MPa). The control group and the PMMA + M&C Primer group exhibited predominantly adhesive failures, while the other groups showed a combination of adhesive and mixed failures.

Conclusion: Super-Bond Universal without primer achieved the highest bond strength, and the application of primers prior to PMMA or resin cement placement significantly improved bonding between Co-Cr alloys and acrylic resin teeth, suggesting that appropriate surface conditioning can enhance denture repair outcomes.

Objective: To evaluate the predictors of tensile strength of nylon and polyglycolic acid when immersed in Peruvian camu camu and tumbo juices.

Methods: An in vitro experimental and comparative study was conducted following the CRIS guidelines for reporting laboratory studies. A total of 192 samples of sutures were tested under laboratory conditions, measuring their initial resistance at days 3, 7, and 14. The juices, prepared in an artisanal way to preserve their natural characteristics, were monitored for pH daily. Mechanical tests were performed using a digital tensile machine, and data were analyzed with Stata 17.0 statistical software using Student's t-tests and linear regression.

Results: Both materials displayed a timewise decrease in strength, with polyglycolic acid being stronger than nylon at all time points measured. At time 0 polyglycolic acid and nylon were noted as 12.23 ± 0.40 N and 8.94 ± 0.17 N, respectively. At day 14 polyglycolic acid and nylon were noted as 11.24 ± 0.38 N and 7.59 ± 0.38 N, respectively. The camu camu juice and the tumbo juice displayed similar effects (p > 0.05), and pH was the only feature to display a significant decrease per unit variation (p < 0.05).

Conclusion: Such a conclusion tends to confirm the greater acid resistance of polyglycolic acid over nylon and adds more weight to pH as a variable affecting suture degradation. We may learn to make more intelligent choices of absorbable sutures at the operating table.

Introduction: Although tooth rotations are a common orthodontic problem, little research has addressed how lay observers perceive these rotations. Consequently, the aim of this study is to determine laypersons' esthetic perceptions of changes in the rotation of the maxillary lateral incisors.

Materials and methods: An intraoral digital scan of a female adult's dentition was manipulated with ClinCheck software to create four smile conditions: (A) no rotation either maxillary lateral incisor, (B) 20° mesial-out rotation of both, (C) 30° mesial-out rotation, and (D) 40° mesial-out rotation. Each condition was shown with frontal and three-quarter view images. A panel of laypeople (age 18-30, no dental training) rated the attractiveness of each smile using a 100 mm visual analog scale (VAS; 0 = least esthetic, 100 = most esthetic). The score for each condition was recorded. A mixed-model two-way ANOVA (gender × rotation) with repeated measures was used to analyze the data.

Results: No-rotation smiles were rated significantly more attractive than any smiles with rotated lateral incisors (p  < 0.05). Smiles with a 40° rotation received the lowest esthetic scores and were significantly less attractive than the others (p  < 0.001). Laypersons did not significantly distinguish between 20° and 30° rotations (p  > 0.05). There was no significant difference in ratings between male and female panelists (p = 0.104). No interaction effect between panelist gender and rotation level was observed.

Conclusion: Laypeople preferred the smile with no rotation of the lateral incisors. They could not perceive a notable esthetic difference between 20° and 30° rotations. However, a 40° rotation was perceived as substantially less esthetic. Panelist gender did not affect esthetic ratings.

Objective: The aim of this study was to evaluate the microleakage beneath orthodontic bands cemented with resin-modified glass ionomer (RMGI), following enamel treatment with two different deproteinizing agents in comparison to a control group.

Materials and methods: Thirty-six human third molars were used for this cross-sectional study. The samples were randomly divided into three equal groups of 12. The method of band cementation in each group was as follows: Group I (6% bromelain enzyme as deproteinizer + GC Fuji plus Conditioner + GC Fuji Plus Glass ionomer), Group II (chlorhexidine [CHX] as deproteinizer + GC Fuji Plus Conditioner + Glass ionomer), and Group III (GC Fuji Plus conditioner + GC fuji plus Glass ionomer) as the control group. All samples were sealed and dyed with methylene blue and then exposed to thermocycling. The samples were sectioned and prepared for microleakage evaluation at both occlusal and gingival sides for the enamel-cement interface margins. A stereomicroscope was used to evaluate the amount of dye penetration as the microleakage. Comparison of the microleakage values among the groups was done using the Kruskal-Wallis and Mann-Whitney U test as the post hoc test.

Results: The 6% bromelain enzyme deproteinization showed the least amount of microleakage at both occlusal and CEJ sides of the bands (p  < 0.05). Group II also showed a better microleakage value at the gingival side in comparison to the control group (p  < 0.05).

Conclusion: This study revealed that the pretreatment of enamel with 6% bromelain enzyme significantly reduced the microleakage beneath orthodontic bands cemented with RMGI cement (RMGIC). Improved marginal sealing by 6% bromelain enzyme was significant compared with that of the CHX pretreatment and untreated enamel surfaces.

Introduction: Martensitic endodontic instruments, thanks to their flexibility, produce less apical transportation compared to austenitic instruments. Recently, a sequence of instruments featuring a dual thermal treatment applied separately to the tip and the shank was introduced with the aim of achieving a tip with enhanced cutting capacity and a more flexible body. The increased stiffness at the tip could potentially lead to greater apical transportation. The aim of this study was to compare apical transportation produced by SlimShaper (single thermal treatment) and SlimShaper PRO (dual thermal treatment) nickel-titanium (NiTi) instruments (Zarc4Endo, Spain) in standardized simulated canals.

Methods: Forty-four standardized J-shaped resin blocks were used, divided into two groups (n = 22): Group A (shaped with SlimShaper up to size 25/0.04) and Group B (shaped with SlimShaper PRO up to size 25/0.04). Each block was photographed before and after shaping, and the images were superimposed to evaluate apical transportation. Data normality was verified with the Shapiro-Wilk test, and homogeneity of variances was assessed with Levene's test. Since assumptions were met, comparisons between the two groups were performed using the independent Student's t test, with the level of significance set at p  < 0.05.

Results: Mean apical transportation was 0.08423 mm (SD 0.01049) for SlimShaper and 0.08609 mm (SD 0.01102) for SlimShaper PRO, with no statistically significant difference between groups (p = 0.57).

Conclusions: Under the conditions of this study, the dual-thermally treated SlimShaper PRO instruments did not produce greater apical transportation than the single-thermally treated SlimShaper instruments.

Introduction: Human papillomavirus (HPV) is associated with several types of oral lesions (OLs), including oropharyngeal squamous cell carcinoma (SCC), especially in HIV-positive individuals.

Objectives: To identify the prevalence and clinical implications of the alpha (α) and beta (β) genera of HPV in the oral cavity and oropharynx of HIV-positive men who have sex with men (MSM).

Methods: A cross-sectional study from January 2022 to May 2023 was performed. Ninety-four participants were included; their sexual habits, risk factors, HIV-1 viral load, and CD4⁺ T-cell counts were obtained. Exfoliative cytology was performed, and deoxyribonucleic acid (DNA) was extracted from the samples to identify α and β HPV genera through endpoint polymerase chain reaction (PCR). OLs associated with HPV infection were described, and histopathological and immunohistochemical findings for p16 were reported.

Results: A total of 71.3% of the participants were positive for any HPV genus (22.4% α-HPV and 49.2% β-HPV). The 6.3% had OLs associated with HPV, principally leukoplakia, and although six of nine samples were p16 positive, none were malignant.

Conclusion: The prevalence of HPV infection in the oral cavity and oropharynx in HIV + MSM was high; however, the associated OLs were infrequent and not malignant. Future studies are necessary to evaluate the clinical relevance of HPV infection and p16-positive OLs.

Orthodontic treatment often lasts around 20 months, and prolonged duration increases the risk of adverse events. Physical adjunctive interventions (PAIs) are proposed to accelerate tooth movement, but their efficacy remains uncertain. This umbrella review synthesized systematic reviews and meta-analyses of randomized clinical trials (RCTs) on PAIs published through March 2025 (PubMed, Web of Science, Scopus, Cochrane Library). Review quality was appraised with the A Measurement Tool to Assess Systematic Reviews-2 (AMSTAR-2) and the Risk of Bias in Systematic Reviews (ROBIS) tools. Study overlap was quantified using the corrected Graphical Representation of Overlap for Overviews (GROOVE) method. Risk of bias in the primary studies was reassessed, when required, using the Cochrane Risk of Bias 2 (RoB 2) tool. Certainty of evidence was rated with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Random-effects models were used when statistical heterogeneity was substantial (I ² > 50%); otherwise, fixed-effects models were used. Effect estimates are reported as mean difference (MD) with 95% confidence intervals (CIs). Seventeen systematic reviews (12 meta-analyses, 5 narrative) covering 76 RCTs were included. Vibration devices showed minimal or no clinically significant acceleration: leveling/alignment MD = 0.05 mm (95% CI: -0.38 to 0.49), canine retraction + 0.27 mm/month (95% CI: 0.19-0.35), en-masse retraction + 0.19 mm/month (95% CI: -0.25 to 0.63) (GRADE: moderate-very low). Low-level laser therapy (LLLT) shortened alignment by -58.4 days (95% CI: -88.6 to -28.2) and, in maxillary extraction, by -28 days (95% CI: -39 to -17), with early canine retraction gains (95% CI: +0.31 to +0.27 mm/month) (GRADE: moderate-very low). Light-emitting diode (LED) therapy showed + 0.005 mm/day (95% CI: -0.001 to 0.012) with small, non-significant monthly estimates (GRADE: low-very low). Bioelectric stimulation (BES) added + 1.78 mm at 3 months (95% CI: 0.99-2.57) (GRADE: low). Overall, methodological quality varied widely, with most reviews rated low to critically low by AMSTAR-2 and at high risk of bias by ROBIS. Vibration should not be the primary accelerator. Photobiomodulation (PBM) is the most promising clinical option, but it requires standardized protocols (wavelength, dose, schedule). BES is promising yet underpowered. Registration: PROSPERO CRD420251043659.