Frontiers in Dentistry最新文献

Dens in dente is a rare structural abnormality arising during tooth development. It is also called dens invaginatus or dilated odontoma, which develops following inward folding (invagination) of the enamel organ into the dental papilla. Maxillary lateral incisors are the most frequently affected teeth. Dens in dente often leads to pulp necrosis and development of a periapical lesion. Also, impacted teeth are one of the reasons for development of odontogenic cysts and tumors. A dentigerous cyst, classified as an odontogenic cyst, develops around the crown of an unerupted tooth. These cysts most frequently involve mandibular third molars; they are also commonly associated with maxillary canines and mandibular second premolars. This report describes a dens in dente in a maxillary lateral incisor, and impacted maxillary canine teeth with extended periodontitis and their management by a combination of root canal and surgical treatments.

Objectives: This study evaluated the effect of bioactive glass (BAG) in different forms on microshear bond strength (µSBS) of composite resin to dentin using a universal adhesive in self-etch (SE) and etch-and-rinse (E&R) modes after different storage times. Materials and Methods: In this in vitro study, 120 extracted human third molars were sectioned 3mm occlusal to their cementoenamel junction to expose dentin. The teeth were then randomly assigned to three groups (n=40): (I) 20% BAG suspension for dentin pretreatment, (II) 1% BAG-modified adhesive (G2-Bond Universal), and (III) BAG-free control group. Each group was subdivided based on the adhesive application mode (SE or E&R) and storage time (immediate at 24 hours, or delayed at 3 months), with 10 teeth per each subgroup. The µSBS was measured by a universal testing machine. Data were analyzed by three-way and two-way ANOVA, followed by the Tukey's post-hoc test (α=0.05). Results: Three-way ANOVA showed significant interaction effect of BAG incorporation and storage time on µSBS (P=0.017); while other interactions were not significant (P>0.05). The effects of BAG incorporation (P=0.951) and application mode (P=0.769) were not significant on immediate µSBS (P>0.05). After 3 months, the 1% BAG-modified adhesive showed a significantly higher µSBS than the 20% BAG suspension (P=0.001) and the control group (P<0.001), with no significant effect of application mode (P=0.417). Conclusion: BAG incorporation did not affect the immediate µSBS of the adhesive but improved its long-term durability, such that the 1% BAG-modified adhesive showed the highest delayed µSBS, regardless of the application mode.

Objectives: This study evaluated the magnitude of generated aerosols and the extent and intensity of splatter during three orthodontic procedures. Materials and Methods: Ten extracted teeth were mounted in a phantom jaw. Acridine orange dye was injected into the water irrigation reservoir. For each procedure, 24 grade-I filter paper discs at 2,4,6,8,10 and 12 o'clock positions at 1, 2,3, and 4ft distances, and 5 additional discs were placed on the operator's face shield and right arm. Three orthodontic procedures (orthodontic bonding, motorized interproximal reduction, and debonding and clean-up of adhesive remnants) were performed. After each procedure, the filter papers were left in place and the operator remained in his position for 30 minutes. The filter papers were analyzed for the amount and concentration of acridine orange dye using a stereomicroscope and a fluorescent microscope. Results: The maximum surface area of contamination was at the 4 o'clock position at 1ft and 2ft. The minimum was at the 10 o'clock position at 1ft distance in all procedures. Contamination of filter papers was found to be maximum on the operator's face shield and minimum on the operator's right arm for all three procedures. The intensity of contamination was similarly maximum at 1ft. distance at the 4 o'clock and 6 o'clock positions for the first procedure and the at 4 o'clock position for the second and third procedures. It was equally minimum at 12, 8 and 10 o'clock positions at 1ft distance in all 3 procedures. Conclusion: Orthodontic procedures can result in localized contamination, highlighting the need for protective equipment for the operator, assistant and patient.

Objectives: The purpose of this study was to compare the clinical performance of coronally advanced flap (CAF) with connective tissue graft (CTG) and vestibular incision subperiosteal tunnel access (VISTA). Materials and Methods: The statistical population of this randomized clinical trial consisted of 24 healthy non-smokers with Miller Class I or II gingival recession (GR) defects, equally divided into two groups of 12 to receive either a CAF or the VISTA technique. Clinical parameters including the clinical attachment level (CAL), gingival biotype, pocket probing depth (PPD), recession height (RH), recession width (RW), root coverage (RC), and keratinized tissue width (KTW) were measured and compared between the two groups using ANCOVA, Fisher's exact test, independent samples t-test, Mann-Whitney U test, and repeated-measures ANOVA (alpha=0.05). Results: The CAF group showed a significantly higher RC percentage (97.22%±9.62%) than the VISTA group (77.22%±24.28%%). Both techniques exhibited similar performance in terms of reducing the PPD and increasing the KTW and gingival attachment. However, the CAF group experienced a significantly greater reduction in CAL, RW, and RH than the VISTA group (P<0.05). Conclusion: The VISTA and CAF groups showed a complete root coverage (CRC) percentage of 33.3% and 91.7%, respectively, indicating higher effectiveness of CAF than VISTA.

Considering the increasing use of dental implants, their failure is a serious challenge encountered by dentists. An accurate prediction of the rate of failure based on the underlying factors allows patients to accept the risk of failure. This study assessed the failure rate and time of implant treatment in patients referred to a specialized clinic. This study was conducted on implant cases in Shahid Montazeri Clinic in Tehran, Iran, from March 2008 to March 2017. A total of 544 patients including 248 patients in the failure group (case) and 296 patients in the treatment success group (control) were evaluated. Data were analyzed using the univariate and multivariable logistic regression. Males, older patients, posterior implant placement site, and shorter height and/or diameter of dental implants increased the risk of failure (P<0.05). The implant brand was also an effective factor in the failure rate (P<0.001). Implants with smaller length or diameter were more prone to failure. Accordingly, in selecting a dental implant, attention should be paid to the patient's age, sex, and location of implant to reduce the failure rate by increasing the diameter and length of implant.

Objectives: This study compared the antimicrobial effects of Endoseal MTA and AH Plus sealers on Enterococcus faecalis (E. faecalis) and Candida albicans (C. albicans) mature biofilms on dentin blocks. Materials and Methods: In this in vitro study, the root canals of 207 dentin blocks sectioned from the roots of extracted teeth were inoculated with E. faecalis and C. albicans, and incubated for 3 weeks. The specimens were evaluated in 12 groups (n=17) for random root canal filling with AH Plus, Endoseal MTA, or no sealer, and assessment after 24 hours and 2 weeks. Dentin chips were cultured on blood agar, and the colonies were counted. One random specimen from each group was assessed under a scanning electron microscope (SEM). Data were analyzed using the Kruskal-Wallis and Mann-Whitney tests with Bonferroni adjustment at 0.05 level of significance. Results: At 24 hours, Endoseal MTA significantly decreased the E. faecalis count compared with the positive control (P<0.008). At 2 weeks, the colony count of both microorganisms was significantly lower in the AH Plus group compared with the control group (P<0.008). The C. albicans colony count in the Endoseal MTA group was significantly lower than that in the control group at 2 weeks (P<0.008). AH Plus caused significantly greater reduction in C. albicans colony count at 2 weeks compared with Endoseal MTA (P<0.008). Conclusion: AH Plus showed a higher antimicrobial activity over time against both E. faecalis and C. albicans. Endoseal MTA only showed short-term antibacterial effect.

Objectives: The prevalence of temporomandibular disorders (TMDs) is increasing in adults, and they are associated with symptoms such as pain and dysfunction. Non-surgical treatment, which may include pharmacotherapy, laser therapy, and physiotherapy, is the first step in treatment of TMDs. This study aimed to compare the effects of naproxen, diclofenac, and piroxicam on TMDs. Materials and Methods: This clinical trial was conducted on 104 patients who were randomly assigned to four groups (n=26) to receive either 500mg naproxen tablets, 50mg diclofenac tablets, 10mg piroxicam capsules, or the placebo. The patients were evaluated for pain, clicking, tenderness, and maximum mouth opening (MMO) in five stages, i.e., before starting the treatment and 1 week, 3 weeks, 5 weeks, and 6 weeks after starting the treatment. Data were analyzed by one-way repeated measures ANOVA with one repeated and one between-subject factor, Fisher's exact test, and Chi-square test (alpha=0.05). Results: Tenderness and clicking decreased with time in all groups (P≤0.05). The mean pain intensity and tenderness were significantly lower in the naproxen group than the other groups (P<0.05). Conclusion: Naproxen tablets can reduce pain and tenderness in TMD patients more than diclofenac tablets, piroxicam capsules, and the placebo.

Objectives: This study evaluated the effects of using a universal adhesive and application of a flowable composite by the snow-plow technique on microleakage of Class II composite restorations in primary molars. Materials and Methods: In this in vitro study, Class II cavities were prepared with their gingival margin at the cementoenamel junction in the proximal surfaces of 90 freshly extracted primary molars. The teeth were then assigned to 3 groups (n=30) for the application of a universal adhesive (Single Bond Universal) in total-etch and self-etch modes and a conventional etch-and-rinse adhesive (Single Bond 2). Each group was divided into 3 subgroups (n=10) for restoration without a flowable liner (control), application of a precured flowable liner, and using a flowable composite as liner by the snow-plow technique. After 1000 thermal cycles, the gingival margin microleakage was evaluated using the fluid filtration technique. Data were analyzed by two-way ANOVA and Tukey's test (alpha=0.05). Results: Type of adhesive, unlike liner application (P=0.579), had a significant effect on microleakage (P=0.01). Application of universal adhesive (whether in self-etch or total-etch mode) resulted in less microleakage than the conventional etch-and-rinse adhesive. There was no statistically significant difference between the two application modes of the universal adhesive (P>0.05). Conclusion: Application of Single Bond universal adhesive for composite restoration of primary molars may improve the marginal seal and decrease microleakage.

Objectives: The aim of this study was to assess the color change (∆E) of teeth following the use of several bleaching protocols with power bleaching. Materials and Methods: This in vitro study evaluated 50 sound incisors and premolars. After cleaning, the teeth were immersed in a 2g/100mL tea solution for 6 days. The samples were randomly divided into 5 bleaching groups: Snow L [containing 40% hydrogen peroxide (HP) and 20% carbamide peroxide] with 980nm diode laser, White Smile (containing 32% HP) with LED (Monitex), Boost (containing 40% HP) with 980nm diode laser, Boost (containing 40% HP) with LED (Monitex), and Boost without activation. Color parameters were measured before and after staining, immediately and 1 week after bleaching by a spectrophotometer, and their ∆E was calculated and compared by one-way ANOVA followed by the Tukey's test. Results: All bleaching protocols improved the color parameters. The ∆E in each group was significant after bleaching compared to before bleaching in the cervical (P<0.001), middle (P<0.001) and incisal (P<0.001) thirds. The ∆E was significant at 1 week compared to before bleaching (P=0.002 for the cervical, P<0.001 for the middle, and P<0.001 for the incisal third, respectively), immediately after bleaching compared with after staining (all Ps<0.001), and also at 1 week compared with after staining (all Ps<0.001). Conclusion: Within the study limitations, all power bleaching protocols caused color change of the teeth. The efficacy of Boost (conventional bleaching), Boost plus LED, and White Smile was better than Snow L regarding color change of teeth.