Assessment of the Acceptable Range of Lips and Chin Position in Two Different Geographical Zones of Iran among Laypersons.

Statement of the Problem: The position of the chin and lips are important components in the lower third of the face and can be changed by orthodontic treatment. It seems that factors such as diversity in culture, ethnicity, and place of residence are among the factors affecting people's perception of beauty. Iran, as a vast country, contains different ethnicities and cultures, and of course, it is not exempt from this point of view. Purpose: Our purpose of conducting this study is to investigate the impact of the difference in living environment and culture on people's aesthetic perception. Orthodontists and oral surgeons can use these data to choose the best treatment plan for the patients according to their geographical zones. Material and Method: A descriptive cross-sectional study was conducted to evaluate the perception of lips and chin position. A series of 25 profile images were prepared in 5 sets. Each set contained 5 profile images. Northern and Southern lay people and orthodontists were asked to evaluate the profile series of each set in 1 session and score them from 1 to 5: 1, very unattractive; 2, unattractive; 3, neither attractive nor unattractive; 4, attractive; or 5, very attractive. Results: 652 participants in 3 groups, including 16 orthodontists (10 men and 6 women), 318 lay people of the North of Iran (172 men and 138 women), and 318 lay people of the South of Iran (175 men and 139 women) participated in this study. Regardless of the chin position, normal lip position and slight changes of that (in both protruded and retruded positions) were more favorable for all three groups. The images with moderately retruded lips were scored as the least attractive by all three groups and orthodontist gave the lowest score to these profiles. Southern people could better tolerate moderately retruded lips than other two groups. In the fifth series, orthodontists preferred slightly and moderately protruded lips in comparison to other two groups of laypeople. Conclusion: Regardless of the chin position, normal and slightly (-2mm to +2mm) protruded and retruded lips were more favorable in all three groups. Southern people could better tolerate moderately retruded lips than the two other groups.

Mechanical properties of combined packable and high-filled flowable composite used for the fixed retainer: an in vitro study.

BACKGROUND: Clinicians often utilize both flowable and packable composites concurrently in bonding fixed retainers. Thus, this study aimed to assess the synergistic effect of these composites in the bonding process. METHODS: This in vitro study divided specimens into three groups: flowable composite (nano-hybrid, Tetric N-Flow, Ivoclar Vivadent), packable composite (nano-hybrid, Tetric N-ceram, Ivoclar Vivadent), and combined use of flowable and packable composite. Shear bond strength (SBS), adhesive remnant index (ARI), and wire pull-out resistance were compared among the groups. Statistical analyses were conducted using ANOVA and Tukey tests to compare study groups. Additionally, Chi-square and Kruskal-Wallis tests were employed to analyze the ARI index among the groups. RESULTS: ANOVA results indicated no statistically significant differences among test groups (P = 0.129) regarding SBS. However, a significant difference existed between flowable and packable composite groups (P = 0.01) regarding ARI scores. Among the study groups, flowable composite exhibited the highest frequencies of ARI scores of 1 and 2, whereas packable composite showed the highest frequency of ARI scores of 0. The combined group had higher frequencies of ARI scores of 0 and 1 compared to the flowable composite. The wire pull-out test revealed that the combined application of flowable and packable composite resulted in significantly lower detachments compared to the packable composite alone (P = 0.008). However, no significant differences were observed in the comparisons between the flowable-packable (P = 0.522) and combined-flowable (P = 0.128) groups. CONCLUSION: The combined use of flowable and packable composites for fixed retainers demonstrated adequate shear bond strength and ideal ARI scores, suggesting it as a suitable adhesive system for bonding orthodontic fixed retainers.

A Comparison of Lower Dental Arch Changes Using Two Types of Space Regainers: A Removable Appliance with a Distalizing Screw and a Fixed Double-Banded Appliance.

Aim: The aim of this study was to compare lower dental arch changes using two types of space regainers, including a removable appliance with a distalizing screw and a fixed double-banded appliance. Methods and Materials: In this case-control study, the study sample was comprised of thirty-eight children with mixed dentitions, all of whom had unilateral space deficiency due to premature loss of the second deciduous molar in the mandibular arch. Patients were treated with either a removable appliance with a distalizing screw or a fixed double-banded space regainer (DBSR) (n = 19). Pre- and posttreatment dental casts and lateral cephalograms of patients were evaluated to compare the effects of the two space-regaining devices on the mandibular dental arch. The data were analyzed using paired and independent t-tests. Results: Available space, molar angle, IMPA, and the first molar distance to the mandibular plane and symphysis increased significantly in both groups (P < 0.001). The mean amount of IMPA changes was significantly greater in the distalizing screw group than in the DBSR group (P < 0.05). But, there were no statistically significant differences between the mean changes of available space, molar angle, and the first molar distance to the mandibular plane and symphysis in the distalizing screw and the DBSR group (P < 0.05). The DBSR group's treatment time was significantly shorter (P < 0.001). Conclusion: The removable device with a distalizing screw and the DBSR were both able to regain mild-to-moderate unilateral space loss, achieving an increase in molar angle, IMPA, and molar extrusion. However, treatment time with the DBSR was shorter and with less incisor tipping as a side effect.

The Effect of Toothpastes Containing Natural Ingredients Such As Theobromine and Caffeine on Enamel Microhardness: An In Vitro Study.

The current study aimed to investigate the effect of biocompatible kinds of toothpastes containing natural ingredients such as theobromine and caffeine on the enamel microhardness after demineralization. 72 maxillary premolar teeth extracted for orthodontic purposes were used in this study. Primary enamel surface microhardness examinations were performed using a Digital Micro Vickers Hardness Tester following the Knoop technique (50 g load for 15 s with three indentations at various points). The specimens were immersed in lactic acid (pH = 5.4) for 7 days, washed with distilled water, dried, and then retested for microhardness. According to the type of toothpaste used for brushing, all specimens were categorized as follows: Group 1, Theodent classic® toothpaste (theobromine); Group 2, Power Energy toothpaste (caffeine); Group 3, Colgate toothpaste (fluoride); and Group 4, distilled water as the negative control. The specimens were retested for enamel microhardness after brushing 2 times a day for one month. After brushing with different types of toothpaste, for all experiment groups, the increase in microhardness values in the demineralized enamel surfaces was significant and there were significant differences between them (p value <0.05). The fluoride group had the highest microhardness and had a significant difference with the caffeine and distilled water groups, but there was no significant difference with the theobromine group (p value <0.05). In the theobromine group, the hardness was considerably higher than in the caffeine and distilled water groups. There was no significant difference between the caffeine and distilled water groups. Theobromine toothpaste had the same remineralization effect as that of fluoride toothpaste, while caffeine toothpaste had no positive effect on the remineralization process.

Therapeutic applications of herbal/synthetic/bio-drug in oral cancer: An update.

Oral cancer, as one of the most prevalent and invasive cancers that invade local tissue, can cause metastasis, and have high mortality. In 2018, around 355,000 worldwide oral cancers occurred and resulted in 177,000 deaths. Estimates for the year 2020 include about 53,260 new cases added to previous year's cases, and the estimated death toll from this cancer in 2020 is about 10,750 deaths more than previous years. Despite recent advances in cancer diagnosis and treatment, unfortunately, 50% of people with cancer cannot be cured. Of course, it should be remembered that the type of treatment used greatly influences patient recovery. There are not many choices when it comes to treating oral cancer. Research efforts focusing on the discovery and evolution of innovative therapeutic approaches for oral cancer are essential. Such traditional methods of treating this type of cancer like surgery and chemotherapy, have evolved dramatically during the past thirty to forty years, but they continue to cause panic among patients due to their side effects. Therefore, it is necessary to study and use drugs that are less risky for the patient as well as to provide solutions to reduce chemotherapy-induced adverse events that prevent many therapeutic risks. As mentioned above, this study examines low-risk therapies such as herbal remedies, biological drugs, and synthetic drugs in the hope that they will be useful to physicians, researchers, and scientists around the world.

Effect of Maxillary Posterior Space Discrepancy on the Molars and Overbite in Class II Malocclusions with Different Vertical Patterns.

AIM: The purpose of this cross-sectional study was to investigate the influence of maxillary posterior space discrepancy (MPDD) on angulation and vertical position of molars in patients with skeletal class II malocclusions, presenting long, short, and normal vertical growth patterns. MATERIALS AND METHODS: In total, 120 lateral cephalograms of patients (mean age: 23 years) with skeletal class II malocclusion were evaluated. Patients were divided into six groups based on their vertical growth pattern (normal, long, and short faces) and the presence or absence of maxillary posterior discrepancy. Maxillary molars' sagittal angulation and vertical position were measured on cephalograms via Dolphin™ three-dimensional (3D) software (version 11.5). The comparison between groups with the same vertical dimension and different status of MPDD was done with independent t test. The analysis of analysis (ANOVA) was used to make pairwise comparison between all six groups. Finally, a multiple regression analysis was performed to evaluate the influence of molar position and MPDD on the anterior overbite. RESULTS: The results showed that the angulation of the maxillary first molar was not statistically different between groups with the same vertical dimension but varied in terms of MPDD. The maxillary second molar was more distally inclined in patients with MPDD than those without MPDD with short and normal facial types (p value = 0.016 and p value = 0.001, respectively). The second molar had significantly more distal angulation in long face patients than short and normal face participants, without considering the status of MPDD. The upper first and second molars were erupted more in patients with long than short or normal faces, without any influence of MPDD. CONCLUSION: The presence of MPDD caused more distal inclination of the maxillary second molar, in skeletal class II patients with short and normal vertical growth patterns. CLINICAL SIGNIFICANCE: The status of MPDD and its effect on the maxillary second molar teeth should be considered in skeletal class II patients with short and normal vertical growth patterns.

Comparison between Classic Twin-block and a Modified Clear Twin-block in Class II, Division 1 Malocclusions: A Randomized Clinical Trial.

AIM: The aim of this study was to compare dentoskeletal effects and patient's satisfaction with a modified twin-block (clear twin-block) and classic twin-block. MATERIALS AND METHODS: A total of 62 patients with skeletal class II malocclusion contributing to mandibular retrognathism with a minimum of 4 mm overjet, the FMA angle between 20 to 25 degree and being in stage 2 to 3 of cervical vertebral maturation participated in this study. Subjects were randomized in 1:1 ratio to classic and clear twin-block. Lateral cephalograms were taken at two stages-Pre- and post-treatment (when the overjet reduced to 1 to 0 mm). All the measurements were done with Dolphin software version 10.5. Four months after the start of the treatment the patients were asked to fill the questioners regarding their compliance from the appliances. RESULTS: Both classic and clear twin-block groups showed mandibular advancement without statistically significant difference between them. However, SNB angle increased slightly more in clear group than the classic one. "Headgear effect" is not statistically noticeable in both groups. However, SNA angle decreased slightly more in classic group. Increased in lower incisors proclination was happening in both groups, but in a clear group, this increase was significantly less. Overbite reduction could be seen in both groups with significantly more reduction in the classic group. CONCLUSION: Increase in lower incisors proclination was less in clear group than the classic one. Overbite reduction was more in the classic group than the classic one. CLINICAL SIGNIFICANCE: Clear twin-block is more beneficial in skeletal class II patients with proclined lower incisors and vertical growth pattern.

Resistance to Sliding in Clear and Metallic Damon 3 and Conventional Edgewise Brackets: an In vitro Study.

STATEMENT OF THE PROBLEM: Frictional forces are considered as important counterforce to orthodontic tooth movement. It is claimed that self-ligating brackets reduce the frictional forces. PURPOSE: The aim of this study was to compare the resistance to sliding in metallic and clear Damon brackets with the conventional brackets in a wet condition. MATERIALS AND METHOD: The samples included 4 types of brackets; metallic and clear Damon brackets and metallic and clear conventional brackets (10 brackets in each group). In this study, stainless steel wires sized 0.019×0.025 were employed and the operator's saliva was used to simulate the conditions of oral cavity. The tidy-modified design was used for simulation of sliding movement. The resistance to sliding and static frictional forces was measured by employing Testometric machine and load cell. RESULTS: The mean (±SD) of resistance to sliding was 194.88 (±26.65) and 226.62 (±39.9) g in the esthetic and metallic Damon brackets, while these values were 187.81(±27.84) and 191.17(±66.68) g for the clear and metallic conventional brackets, respectively. Static frictional forces were 206.4(±42.45) and 210.38(±15.89) g in the esthetic and metallic Damon brackets and 220.63(±49.29) and 215.13(±62.38) g in the clear and metallic conventional brackets. According to two-way ANOVA, no significant difference was observed between the two bracket materials (clear and metal) and the two types of bracket (self-ligating versus conventional) regarding resistance to sliding (p= 0.17 and p= 0.23, respectively) and static frictional forces (p= 0.55 and p= 0.96, respectively). CONCLUSION: Neither the type of bracket materials nor their type of ligation made difference in resistance to sliding and static friction.