Purpose: This study evaluated how the formation of various types of precipitates affects the accuracy of electronic apex locators in determining the working length.

Methods: Two hundred and forty extracted human maxillary incisors were selected. A total of eight groups were used: four groups (n = 30) for the application of different irrigants; saline, sodium hypochlorite (5.25% NaOCl), chlorhexidine (2% CHX) and ethylenediaminetetraacetic acid (EDTA) (17% EDTA), and four groups (n = 30) for the formation of precipitates; orange-brown (2% CHX + 5.25% NaOCl), orange-white (2% CHX + 0.16% NaOCl), white milky (2% CHX + 17% EDTA), salt (2% CHX + saline). Electronic working length was determined by two different electronic apex locators.

Results: The success rate of the 5.25% NaOCl group was significantly higher than that of the white milky precipitate group. The electronic apex locators were highly effective in identifying working length, but the success rate of both devices declined due to the production of a white milky precipitate.

Conclusion: The study emphasizes the importance of selecting appropriate irrigation protocols for optimal treatment outcomes, as the chemical interactions between solutions and precipitates significantly influence electronic apex locator measurements, highlighting the need for careful consideration of irrigant compatibility.

Purpose: To evaluate the effect of die spacer thickness on the fit and load to failure of cantilever resin-bonded fixed dental prostheses (RBFDPs).

Methods: Two identical maxillary RBFDPs with a retainer on the canine were designed to replace a lateral incisor. One design involved a closely fitting retainer with no die spacer (NDS), and the other included an 80-µm die spacer (DS). A total of 10 RBFDPs were produced for each group by selective laser melting. To simulate a natural canine abutment, lithium disilicate abutments were fabricated digitally. After bonding the RBFDP with an adhesive resin luting agent, the marginal fit was measured, and the specimens were then loaded until failure of the luting agent.

Results: The mean marginal fit in the NDS and DS groups was 79.1 µm and 75.7 µm, respectively, and the corresponding mean maximum load to failure was 272.8 N and 254.7 N, respectively. The inter-group differences in these values were not significant.

Conclusion: The inclusion of a RBFDP die spacer had no effect on the marginal fit and maximum load to failure. In addition, the die spacer had no significant effect on the pattern of resin luting agent failure.

Purpose: This study used descriptive and inferential statistics to evaluate healing complications and survival time of avulsed permanent teeth.

Methods: Records of children and adolescents with avulsion injury were identified, and data on age, gender, cause of trauma, number of affected teeth, and status of other teeth and supporting tissues were analyzed. In addition, data on root formation status, duration and medium of extraoral storage, and healing complications of avulsed and replanted permanent teeth were obtained for patients who attended follow-up appointments.

Results: During a period of almost 20 years, 187 permanent teeth of 138 patients were avulsed. Avulsion injuries were more frequent in males and at 10-12 years of age. Falls were the main cause of avulsion, and the teeth most frequently affected were the maxillary central incisors. Seventeen of 51 replanted and followed teeth were retained. Retention was shorter for teeth stored in dry medium. Duration of tooth retention was positively correlated with patient age at the time of trauma. The most common healing complications were ankylosis (70.6%) and inflammatory root resorption (54.9%).

Conclusion: Outcomes of traumatic injuries are multifactorial, and favorable storage conditions, shorter duration of extraoral storage, and biological response are important for survival of avulsed teeth.

Purpose: This study aimed to evaluate the removal efficiency of three different intracanal medicaments using either single-syringe irrigation (S-SI) or multiple ultrasonic-activated irrigation (M-UAI).

Methods: Forty-two extracted human mandibular premolars were prepared to a size of 30/0.06 taper and randomly assigned to two irrigation groups: S-SI and M-UAI. Each group was subdivided based on the intracanal medicament used: Calcipex II (calcium hydroxide-based; CP), Calfee paste (calcium hydroxide-based; CF), or Bio-C Temp (calcium silicate-based; BT) (n = 7 each). After 1 week of storage under 100% humidity at 37°C, the samples underwent removal using either S-SI (1.5 mL sodium hypochlorite, 30 s) or M-UAI (1.5 mL, sequentially: 17% ethylenediaminetetraacetic acid, distilled water, 6% sodium hypochlorite, and distilled water, with 30-s activation for each). Residual intracanal medicament volume was assessed using micro-computed tomography. Statistical analysis was performed using the Kruskal-Wallis test and Mann-Whitney U test (α = 0.05).

Results: In S-SI, CF was removed more effectively than CP. In M-UAI, CF and CP showed similar rates, whereas BT had a significantly lower removal rate.

Conclusion: Removal efficiency varied among medicaments. CF demonstrated superior removability under both S-SI and M-UAI protocols compared with CP and BT.

Purpose: Human dental caries is a troublesome disorder of the teeth, and the bacterium mostly responsible is Streptococcus mutans. The Cbm and Cnm genes, which encode the Cbm and Cnm proteins respectively, are two of the virulence factors associated with Streptococcus mutans strains. Oral appliances such as dental arches and brackets accelerate streptococcal colonization and caries formation. The aim of this study was to determine the gene frequency of Cnm and Cbm in Streptococcus mutans strains isolated from oral arches and brackets in orthodontics patients and their relationship to antibiotic resistance.

Methods: Four hundred seventy-three orthodontics patients were included in this study and 384 Streptococcus mutans strains were isolated from the arches and brackets of these patients. The strains were identified and verified using a Vitek-2 compact system and their antibiotic susceptibility was determined by the disc diffusion method. The presence of the Cbm and Cnm genes was confirmed by the PCR method.

Results: It was found that 2.08% of the strains the Cbm gene and 16.14% the Cnm gene. The rate of co-existence of these two genes was 0.78%.

Conclusion: Strains those harbored the Cbm and Cnm genes are more resistant to antibiotics and more likely to be major risk factors for caries in orthodontic patients.

Purpose: This study investigated the fluorescence intensity and color changes of tooth-colored dental materials under experimental conditions similar to those of charred bodies, from which dental evidence can be obtained.

Methods: Among 160 composite resin (CR) and glass ionomer cement samples, the fluorescence intensity was measured using a spectrofluorometer. CIELAB color space (L*a*b*), difference in lightness (ΔL*), and CIEDE2000 color difference (ΔE00) were calculated for all samples.

Results: The fluorescence intensity of CR was significantly higher in the flow type than in the paste type, and the A1 shade showed significantly higher intensity than the A3 before and after heating. The flow and paste type of the universal shade type CRs showed similar fluorescence to the A1 of conventional CRs before heating and tended to lose its fluorescence and transparency upon heating more easily than the conventional CRs. CR fluorescence intensity decreased significantly after 10 min of heating at 300°C, and many samples lost their fluorescence after 30 min. In contrast, glass ionomer cement fluorescence intensity increased with heating. ΔL* and ΔE00 were consistent with the macroscopic findings.

Conclusion: The findings of this study provide updated information on tooth-colored dental materials and help us understand the circumstances in charred cases.

Purpose: As the anatomy of proximal contact areas affects the risk of dental caries in primary molars, this study aimed to assess the impact of different resin and matrix systems on the geometry of reproduced proximal surfaces in primary molars.

Methods: Sixty mandibular primary first molar typodont teeth were prepared with standardized disto-occlusal cavities. Two experimental groups were created: Group I utilized GC UniFil Flow and Filtek Z250 XT; Group II utilized SDR Plus Bulk Fill Flowable Composite and Ceram.x Spectra ST. Each group was further subdivided into the Palodent V3 sectional matrix system (P) and the Tofflemire matrix system (T). Digital evaluations were then performed to calculate discrepancies.

Results: Significant discrepancies were found only between Group IT and Group IIP in the middle third (P < 0.05). Average root mean square values at proximal contact surfaces did not differ significantly among the groups. The proximal surface shape was also not significantly different.

Conclusion: Within the limits of this study, the reproduced proximal surface geometry was not significantly affected by the type of resin and matrix system.

This study aimed to evaluate the stick behavior and performance of an adhesive for facial prostheses on esthetics and strength. Forty subjects participated in this study. Mimic the skin was fabricated, applied to one cheek of each subject using only medical adhesive, and to the opposite cheek using the same medical adhesive and an overlying film dressing. Ninety-five percent of subjects reported that the silicone prosthesis with film dressing did not peel off and was less noticeable. The combination of medical adhesive and film dressing provided stronger adhesion and better esthetics compared to medical adhesive alone.