Treatment decision analysis for palatally-displaced canines based on orthodontists' opinion and CBCT.

OBJECTIVES: The aim of this study was to assess difficulty of treatment of palatally-displaced canines (PDC) according to experts' opinion using CBCT data and to determine a cut-off point for extraction versus forced eruption. SUBJECTS AND METHODS: Seven CBCT variables of thirty PDC cases were measured with Dolphin 3D software. In addition to measurements of each case, nine 3D and 2D views were prepared on one page and uploaded on the website (canineimpaction.com). Thirty-four orthodontists were asked to judge the difficulty of bringing the impacted canine into occlusal plane. Then, they scored from 1 to 5 the effect of each variable on treatment difficulty and also decided whether to force-erupt or extract the impacted tooth. RESULTS: Overlap in frontal view, angulation of the canine to the occlusal plan, vertical distance to the occlusal plane, age, dilaceration and rotation had significant relationship with the level of treatment difficulty. The treatment plan decision for PDC with treatment difficulty>7.5 was extraction rather than forced eruption. CONCLUSION: We can predict treatment difficulty of PDC by measuring CBCT variables and decide to extract or force-erupt with a reasonable level of agreement among a panel of orthodontists.

Efficacy of a Newly Designed Cephalometric Analysis Software for McNamara Analysis in Comparison with Dolphin Software.

OBJECTIVES: Cephalometric norms of McNamara analysis have been studied in various populations due to their optimal efficiency. Dolphin cephalometric software greatly enhances the conduction of this analysis for orthodontic measurements. However, Dolphin is very expensive and cannot be afforded by many clinicians in developing countries. A suitable alternative software program in Farsi/English will greatly help Farsi speaking clinicians. The present study aimed to develop an affordable Iranian cephalometric analysis software program and compare it with Dolphin, the standard software available on the market for cephalometric analysis. MATERIALS AND METHODS: In this diagnostic, descriptive study, 150 lateral cephalograms of normal occlusion individuals were selected in Mashhad and Qazvin, two major cities of Iran mainly populated with Fars ethnicity, the main Iranian ethnic group. After tracing the cephalograms, the McNamara analysis standards were measured both with Dolphin and the new software. The cephalometric software was designed using Microsoft Visual C++ program in Windows XP. Measurements made with the new software were compared with those of Dolphin software on both series of cephalograms. The validity and reliability were tested using intra-class correlation coefficient. RESULTS: Calculations showed a very high correlation between the results of the Iranian cephalometric analysis software and Dolphin. This confirms the validity and optimal efficacy of the newly designed software (ICC 0.570-1.0). CONCLUSION: According to our results, the newly designed software has acceptable validity and reliability and can be used for orthodontic diagnosis, treatment planning and assessment of treatment outcome.

Color Stability of Enamel following Different Acid Etching and Color Exposure Times.

Background and aims. The aim of this study was to evaluate the effect of different etching times on enamel color stability after immediate versus delayed exposure to colored artificial saliva (CAS). Materials and methods. Human first premolars were divided into five groups of twenty. A colorimeter was used according to the CIE system on the mid-buccal and mid-lingual surfaces to evaluate initial tooth color. Samples in group A remained unetched. In groups B to E, buccal and lingual surfaces were initially etched with phosphoric acid for 15 and 60 seconds, respectively. Then, the samples in groups A and C were immersed in colored artificial saliva (cola+saliva). In group B, the teeth were immersed in simple artificial saliva (AS). Samples in groups D and E were immersed in AS for 24 and 72 hours, respectively before being immersed in colored AS. The teeth were immersed for one month in each solution before color measurement. During the test period, the teeth were retrieved from the staining solution and stored in AS for five minutes. This was repeated 60 times. Color changes of buccal and lingual surfaces were calculated. Kruskal-Wallis and Wilcoxon tests were used for statistical analysis (α ≤0.05). Results. There were no significant differences between the groups in term of ΔE of buccal (P = 0.148) and lingual surfaces (P = 0.73). Conclusion. Extended time of etching did not result in significant enamel color change. Immediate and delayed exposure of etched enamel to staining solutions did not result in clinically detectable tooth color changes.

Clinical Evaluation of Etched Enamel Discoloration following Immediate and Delayed Exposure to Colored Agents.

Introduction. The aim was to evaluate etched enamel discoloration following immediate and delayed exposure to colored agents. Method & Material. 64 premolars were divided into four groups. Buccal surface of the teeth was divided into two halves and baseline color values were measured. One half was covered and the other half was etched and dried. In first and second groups, the patients did not eat any colored agents for the next 24 hours. Both halves were colorimetered after 48 hours and 1 month, respectively. In third and fourth groups, the process was similar, but the patients drank cola and avoid eating any other colored agents and the teeth were colorimetered after 48 hours and 1 month, respectively. Color change values (ΔE) of each half were calculated according to CIE lab system. Sign test was used to compare values of etched and unetched halves. P < 0.08 was set as significant. Results. A significant difference was observed in groups III and IV regarding comparison of ΔE of the etched and control enamel (P = 0.077). Conclusion. Exposure of etched enamel to colored agents in the first 24 hours after etching can affect its color which remains at least for one month.

The efficacy of Er,Cr:YSGG laser in reconditioning of metallic orthodontic brackets.

OBJECTIVE: This study aimed to evaluate the efficiency of erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in removing adhesive from bracket bases, and its influence on shear bond strength (SBS) of orthodontic brackets, compared to several other recycling methods. BACKGROUND DATA: Reconditioning the dislodged attachments is frequently required in orthodontic practice to reduce treatment costs. MATERIALS AND METHODS: Seventy-five premolar teeth were selected and divided into five groups. In groups 1 to 4, brackets recycled with different methods were bonded on the tooth surface, whereas in group 5, new brackets were used. The recycling methods were: silicon carbide stone grinding (group 1), aluminum oxide sandblasting (group 2), and Er,Cr:YSGG laser operated at 3.5 W (group 3) and at 4 W (group 4). The quantitative amount of remaining adhesive on the bracket base was determined after recycling using stereomicroscopic images, and the SBS values were measured. RESULTS: The percentage of adhesive remnants was significantly lower in brackets cleaned with aluminum oxide sandblasting, and significantly higher in those grinded by silicon carbide stone (p<0.05). Brackets cleaned with silicon carbide stone produced the lowest, and those prepared by aluminum oxide blasting or Er,Cr:YSGG laser produced the highest SBS among the groups (p<0.05). There was a significant correlation between changes in percentage of remaining adhesive on the base after recycling with changes in SBS (Pearson r=-0.41, p<0.0001). CONCLUSIONS: Under the study conditions, both aluminum oxide blasting and Er,Cr:YSGG laser were efficient in removing adhesive from bracket bases, and resulted in significantly higher bond strength than for new brackets.

Progesterone effects on experimental tooth movement in rabbits.

The effect of progesterone on tooth movement was evaluated for nine weeks. Twenty-four rabbits were assigned into three groups of long-term, short-term and no progesterone injection. Orthodontic force was applied to incisors for three weeks. Statistical tests showed no significant difference at the seventh and eighth week; but at the ninth week, tooth movement was significantly lower in the long-term group. Long-term progesterone administration could reduce the rate of tooth movement.

Evaluation of the Divine Proportion in the facial profile of young females.

BACKGROUND: Beauty is the phenomenon of experiencing pleasure, through the perception of balance. According to some authors, attractive faces have ideal proportions that are related to the Divine Proportion (1.618:1). AIM: The purpose of this study was to evaluate the Divine Proportion in the human profile and investigate the effects of this ratio on the perception of the beauty of the profile. STUDY AND DESIGN: We conducted a cross-sectional study to determine the mentioned aims. MATERIALS AND METHODS: In this cross-sectional study, fifty females in the age range of 20-25 years, with acceptable profiles were selected. Standardized profile silhouettes were each given a score by 20 judges (consisting of 10 men and 10 women) using the visual analog scale. Five landmarks were determined and five ratios were measured on the silhouettes by using the adobe photoshop program. STATISTICAL ANALYSIS: The Student's t test was used to compare profile proportions of the subjects. RESULTS: Statistical analysis showed none of the proportions had the mean of 1.618, but in subjects having higher esthetic scores, trichion (Te)-soft tissue menton (Me):Tr-subnasale (Sn) and Tr-Me:soft tissue nasion (N)-Me, with the mean of 1.58 were closer to Divine Proportion. CONCLUSIONS: The results suggested the perception of beauty is influenced by the Divine Proportions and Tr-Me:Tr-Sn and Tr-Me:N-Me are the most influential ratios in the perception of the beauty of profile; however, if the Divine Proportion is to be used in treatment planning, it should be used along with other factors.

Forced eruption of adjoining maxillary premolars using a removable orthodontic appliance: a case report.

Forced eruption can be performed in teeth with caries, fracture, resorption or perforation in the cervical third of the root or isolated teeth with one- or two-walled vertical periodontal defects. The purpose of this case report is to introduce an innovative orthodontic appliance which enables forced eruption. This appliance is easy to fabricate, cost-effective and very effective in forced eruption of non-restorable teeth.