The extraction of third molars is a common task carried out at dental/surgery clinics. Postoperative pain is one of the two most common complications of this surgery, along with dry socket. Knowledge of the frequent risk factors of this complication is useful in determining high-risk patients, planning treatment, and preparing the patients mentally. Since the risk factors for postoperative pain have never been summarized before while the risk factors for dry socket have been highly debated, this report summarizes the literature regarding the common predictors of postextraction pain. Except for surgical difficulty and the surgeon's experience, the influences of other risk factors (age, gender and oral contraceptive use) were rather inconclusive. The case of a female gender or oral contraceptive effect might mainly be associated with estrogen levels (when it comes to dry socket), which can differ considerably from case to case. Improvement in and unification of statistical and diagnostic methods seem necessary. In addition, each risk factor was actually a combination of various independent variables, which should instead be targeted in more comprehensive studies.
Contraceptive Agents ; Dry Socket ; Estrogens ; Female ; Humans ; Molar, Third* ; Pain, Postoperative* ; Risk Factors*

PURPOSE: Heat of composite polymerization (HP) indicates setting efficacy and temperature increase of composite in clinical procedures. The purpose of this in vitro experimental study was to evaluate the effects of 5 temperatures on HP of two new composites. MATERIALS AND METHODS: From each material (Core Max II [CM] and King Dental [KD]), 5 groups of 5 specimens each were prepared and their total HPs (J/gr) were measured and recorded, at one of the constant temperatures 0degrees C, 15degrees C, 23degrees C, 37degrees C and 60degrees C (2 x 5 x 5 specimens) using a differential scanning calorimetry (DSC) analyzer. The data were analyzed using a two-way ANOVA, a Tukey's test, an independent-samples t-test, and a linear regression analysis (alpha=0.05). RESULTS: No polymerization reactions occurred at 0degrees C; then this temperature was excluded from statistical analyses. The mean HP of the remaining 20 KD specimens was 20.5 +/- 14.9 J/gr, while it was 40.7 +/- 12.9 J/gr for CM. The independent-samples t-test showed that there were significant differences between the HP of the two materials at the temperatures 15degrees C (P=.0001), 23degrees C (P=.0163), 37degrees C (P=.0039), and 60degrees C (P=.0106). Linear regression analysis showed statistically significant correlations between environment temperatures and HP of CM (R2=0.777). CONCLUSION: Using CM is advantageous over conventional composite because of its better polymerization capacity. However due to its high HP, further studies should assess its temperature increase in vivo. Preheating KD is recommended. Refrigerating composites can negatively affect their polymerization potential.
Calorimetry, Differential Scanning ; Composite Resins ; Dental Materials ; Differential Thermal Analysis ; Hot Temperature ; Linear Models ; Polymerization ; Polymers ; Refrigeration

OBJECTIVES: This study was performed to assess the anatomy of mandibular first molars. MATERIALS AND METHODS: In this in vivo study, cone-beam computed tomography (CBCT) volumes of 312 bilateral intact first mandibular molars from 156 patients (79 men and 77 women; average age, 35.6 ± 11.2 years) were investigated in terms of the direction of each canal's curvature in the buccolingual and mesiodistal dimensions (direction of the position of the apex in relation to the longitudinal axis of the root), the presence of an isthmus (a narrow, ribbon-shaped communication between 2 root canals) in 3 segments (0–2, 2–4, and 4–6 mm) from the apex), and the presence and number of accessory canals (smaller canals besides the main root canals, connecting the pulp to the periodontium). Data were analyzed statistically (α = 0.05). RESULTS: Mesiolingual canals were mostly buccally and distally inclined, while mesiobuccal and distolingual canals were mostly distally curved. Isthmuses were more common in younger patients (χ2 test, p < 0.05). The average numbers of accessory canals in the apical, middle, and coronal segments were 9.9 ± 4.2, 6.9 ± 2.9, and 9.3 ± 3.0 canals per segment, respectively (analysis of variance, p < 0.001). Age and sex were not associated with the number of accessory canals (p > 0.05). CONCLUSIONS The complex anatomy of these teeth deserves attention during non-surgical or surgical endodontic treatment. Around the apex, isthmuses might be more prevalent in younger and female individuals.

OBJECTIVES: This study was performed to assess the anatomy of mandibular first molars.MATERIALS AND METHODS: In this in vivo study, cone-beam computed tomography (CBCT) volumes of 312 bilateral intact first mandibular molars from 156 patients (79 men and 77 women; average age, 35.6 ± 11.2 years) were investigated in terms of the direction of each canal's curvature in the buccolingual and mesiodistal dimensions (direction of the position of the apex in relation to the longitudinal axis of the root), the presence of an isthmus (a narrow, ribbon-shaped communication between 2 root canals) in 3 segments (0–2, 2–4, and 4–6 mm) from the apex), and the presence and number of accessory canals (smaller canals besides the main root canals, connecting the pulp to the periodontium). Data were analyzed statistically (α = 0.05).RESULTS: Mesiolingual canals were mostly buccally and distally inclined, while mesiobuccal and distolingual canals were mostly distally curved. Isthmuses were more common in younger patients (χ2 test, p < 0.05). The average numbers of accessory canals in the apical, middle, and coronal segments were 9.9 ± 4.2, 6.9 ± 2.9, and 9.3 ± 3.0 canals per segment, respectively (analysis of variance, p < 0.001). Age and sex were not associated with the number of accessory canals (p > 0.05).CONCLUSIONS: The complex anatomy of these teeth deserves attention during non-surgical or surgical endodontic treatment. Around the apex, isthmuses might be more prevalent in younger and female individuals.
Cone-Beam Computed Tomography ; Dental Pulp Cavity ; Endodontics ; Female ; Humans ; Male ; Molar ; Tooth

PURPOSE: Bonding agents (BA) are the crucial weak link of composite restorations. Since the commercial materials' compositions are not disclosed, studies to formulize the optimum ratios of different components are of value. The aim of this study was to find a proper formula of BAs. MATERIALS AND METHODS: This explorative experimental in vitro study was composed of 4 different sets of extensive experiments. A commercial BA and 7 experimental formulas were compared in terms of degree of conversion (5 experimental formulas), shear bond strength, mode of failure, and microleakage (3 experimental formulas). Statistical analyses were performed (alpha=.05). The DC of selected formula was tested one year later. RESULTS: The two-way ANOVA indicated a significant difference between the shear bond strength (SBS) of two tissues (dentin vs. enamel, P=.0001) in a way that dentinal bonds were weaker. However, there was no difference between the four materials (P=.283). The adhesive mode of failure was predominant in all groups. No differences between the microleakage of the four materials at occlusal (P=.788) or gingival (P=.508) sites were detected (Kruskal-Wallis). The Mann-Whitney U test showed a significant difference between the microleakage of all materials (3 experimental formulas and a commercial material) together at the occlusal site versus the gingival site (P=.041). CONCLUSION: A formula with 62% bisphenol A-glycidyl methacrylate (Bis-GMA), 37% hydroxy ethyl methacrylate (HEMA), 0.3% camphorquinone (CQ), and 0.7% dimethyl-para-toluidine (DMPT) seems a proper formula for mass production. The microleakage and SBS might be respectively higher and lower on dentin compared to enamel.
Adhesives ; Bisphenol A-Glycidyl Methacrylate ; Dental Enamel ; Dentin* ; Dentin-Bonding Agents ; Polymerization* ; Polymers* ; Tooth*

OBJECTIVE: The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. METHODS: This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (alpha < 0.05). RESULTS: The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 +/- 915 Adegrees, 1,378 +/- 372 Adegrees, 2,444 +/- 369 Adegrees, and 5,242 +/- 2,832 Adegrees, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 +/- 210 Adegrees, 1,831 +/- 1,156 Adegrees, and 4,018 +/- 2,214 Adegrees, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. CONCLUSIONS: The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires.
Microscopy, Electron, Scanning ; Orthodontics ; Stainless Steel

OBJECTIVE: Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. METHODS: In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (α = 0.05). RESULTS: In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). CONCLUSIONS: Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results.
Humans ; Kaplan-Meier Estimate ; Ligation ; Prospective Studies ; Research Design ; Survival Analysis* ; Survival Rate

OBJECTIVE: Our aim was to determine the correlation between dental treatment need as assessed by the components of the index of orthodontic treatment need (IOTN) and a self-evaluation questionnaire in a population selected from the dental clinics of Shiraz, Iran. METHODS: The dental treatment needs of 240 participants (120 men and 120 women) were measured on the basis of the IOTN dental health component (IOTN-DHC), IOTN aesthetic component (IOTN-AC), IOTN AC determined by the examiner (IOTN-ACE), and a self-evaluation questionnaire (SEQ). The correlations between the treatment needs assessed by all the methods as well as the correlations of the treatment needs with age and gender were assessed using a Spearman's correlation coefficient (alpha = 0.01). RESULTS: All methods were significantly correlated (p < or = 0.001). The associations of IOTN-ACE with IOTN-DHC and SEQ were moderately significant (rho = 0.49 and 0.41, respectively). The associations of IOTN-AC with IOTN-DHC and SEQ were weakly significant (rho = 0.24 and 0.35, respectively). The IOTN-DHC was moderately associated with SEQ (rho = 0.53). Gender and age were not associated with treatment needs estimated by any of the methods used (p > 0.06). CONCLUSIONS: The correlations between the self-evaluation and the IOTN components in young adults were close to those reported in children, and IOTN-ACE was more reliable than IOTN-AC.
Child ; Dental Clinics ; Diagnostic Self Evaluation ; Humans ; Index of Orthodontic Treatment Need ; Male ; Surveys and Questionnaires ; Young Adult

OBJECTIVES: One of the most common complications of bilateral sagittal split ramus osteotomy (BSSRO) is neurosensory impairment of the inferior alveolar nerve (IAN). Accurate preoperative determination of the position of the IAN canal within the mandible using cone-beam computed tomography (CBCT) is recommended to prevent IAN dysfunction during BSSRO and facilitate neurosensory improvement after BSSRO. MATERIALS AND METHODS: This randomized clinical trial consisted of 86 surgical sites in 43 patients (30 females and 13 males), including 21 cases (42 sides) and 22 controls (44 sides). Panoramic and lateral cephalographs were obtained from all patients. In the experimental group, CBCT was also performed from both sides of the ramus and mandibular body. Neurosensory function of the IAN was subjectively assessed using a 5-point scale preoperatively and 7 days, 1 month, 3 months, 6 months, and 12 months post-surgery. Data were analyzed using Fisher's test, Spearman's test, t-test, linear mixed-model regression, and repeated-measures ANCOVA (α=0.05, 0.01). RESULTS: Mean sensory scores in the control group were 1.57, 2.61, 3.34, 3.73, and 4.20 over one year and were 1.69, 3.00, 3.60, 4.19, and 4.48 in the CBCT group. Significant effects were detected for CBCT intervention (P=0.002) and jaw side (P=0.003) but not for age (P=0.617) or displacement extent (P=0.122). CONCLUSION Preoperative use of CBCT may help surgeons to practice more conservative surgery. Neurosensory deficits might heal faster on the right side.

Objective: Body dysmorphic disorder (BDD) is a form of obsessive-compulsive disorder that may be negatively associated with the self-image. It might be associated with orthodontic treatment demand and outcome, and therefore is important. Thus, this study was conducted. Methods: The Yale-Brown ObsessiveCompulsive Scale modified for Body Dysmorphic Disorder (BDD-YBOCS) questionnaire was used in 699 orthodontic patients above 12 years of age (222 males, 477 females), at seven clinics in two cities (2020–2021). BDD diagnosis and severity were calculated based on the first 3 items and all 12 items of the questionnaire. The dental health component of the index of orthodontic treatment need (IOTN-DHC) was assessed by orthodontists. Multivariable and bivariable statistical analyses were performed on ordinal and dichotomized BDD diagnoses to assess potentially associated factors (IOTN-DHC, age, sex, marital status, education level, and previous orthodontic consultation) (α = 0.05). Results: IOTN-DHC scores 1–5 were seen in 13.0%, 39.9%, 29.8%, 12.4%, and 4.9% of patients. Age/sex/ marital status/education were not associated with IOTN-DHC (p > 0.05). Based on 3-item questionnaire, 17.02% of patients had BDD (14.02% mild). Based on 12-item questionnaire, 2.86% had BDD. BDD was more prevalent or severer in females, married patients, patients with a previous history of orthodontic consultation, and patients with milder IOTN-DHCs (p< 0.05). Conclusions IOTNDHC was negatively/slightly associated with BDD in orthodontic patients. Being female and married may increase BDD risk.