Comparison of three different sterilization and disinfection methods on orthodontic markers.

BACKGROUND: Marking pencils which are frequently used in orthodontics may cause microbial contamination. The purpose of this study was to evaluate and compare the effectiveness of three disinfection and sterilization methods (autoclave, glutaraldehyde solution, and Deconex spray) on orthodontic markers. MATERIALS AND METHODS: One hundred and twenty orthodontic markers were divided into four groups each 30 pencils: One control group and three groups for three different disinfection/sterilization methods. To evaluate the effectiveness of these methods, pencils were initially contaminated by common pathogen by immersing the pencils in a suspension containing 1.5 × 10(8) CFU/ml organisms. Then, the pencils were subjected to corresponding disinfection/sterilization methods, and the number of remaining microorganisms was calculated and compared with control group. RESULTS: In the control group, the mean number of Escherichia coli was significantly higher than the other two microorganisms (P = 0.01, P = 0.031). However, the mean numbers of Staphylococcus aureus and Candida albicans were not significantly different (P = 0.1). After sterilization with autoclave and glutaraldehyde, no microbial growth was observed, whereas after disinfection with Deconx spray some colonies of microorganisms still could be observed. CONCLUSION: Autoclaving and glutaraldehyde solution are the best methods for disinfecting orthodontic markers.

Success of Maxillary Alveolar Defect Repair in Rats Using Osteoblast-Differentiated Human Deciduous Dental Pulp Stem Cells.

PURPOSE: The use of cell-based therapies represents one of the most advanced methods for enhancing the regenerative response in craniofacial abnormalities. The main aim of this study was to evaluate the regenerative potential of human dental pulp stem cells, isolated from deciduous teeth, for reconstructing maxillary alveolar defects in Wistar rats. MATERIALS AND METHODS: Human deciduous dental pulp stem cells were isolated and stimulated to differentiate into osteoblasts in culture media. Maxillary alveolar defects were created in 60 Wistar rats by a surgical procedure. Then, on the basis of the type of graft used to repair the bone defect, the rats were divided into 6 equal groups: groups 1 and 2, transplantation of iliac bone graft; groups 3 and 4, transplantation of stem cells derived from deciduous dental pulp in addition to collagen matrix; groups 5 and 6, transplantation of just collagen matrix. Then, fetal bone formation, granulation tissue, fibrous tissue, and inflammatory tissue were evaluated by hematoxylin-eosin staining at 1 month (groups 1, 3, and 5) and 2 months (groups 2, 4, and 6) after surgery, and data were analyzed and compared using the Fisher exact test. RESULTS: Maximum fetal bone formation occurred in group 2, in which iliac bone graft was inserted into the defect area for 2 months; there also were significant differences among the groups for bone formation (P = .009). In the 1-month groups, there were no significant differences between the control and stem cell-plus-scaffold groups. There were significant differences between the 2-month groups for fetal bone formation only between the control and scaffold groups (P = .026). CONCLUSIONS: The study showed that human dental pulp stem cells are an additional cell resource for repairing maxillary alveolar defects in rats and constitute a promising model for reconstruction of human maxillary alveolar defects in patients with cleft lip and palate.

How Is the Enamel Affected by Different Orthodontic Bonding Agents and Polishing Techniques?

OBJECTIVES: The objective of this study was to assess the effect of new bonding techniques on enamel surface. MATERIALS AND METHODS: Sixty upper central incisors were randomly divided into two equal groups. In the first group, metal brackets were bonded using TransbondXT and, in the second group, the same brackets were bonded with Maxcem Elite. The shear bond strength (SBS) of both agents to enamel was measured and the number and length of enamel cracks before bonding, after debonding and after polishing were compared. The number of visible cracks and the adhesive remnant index (ARI) scores in each group were also measured. RESULTS: There were significantly more enamel cracks in the Transbond XT group after debonding and polishing compared to the Maxcem Elite group. There was no significant difference in the length of enamel cracks between the two groups; but, in each group, a significant increase in the length of enamel cracks was noticeable after debonding. Polishing did not cause any statistically significant change in crack length. The SBS of Maxcem Elite was significantly lower than that of Transbond XT (95% confidence interval). CONCLUSION: Maxcem Elite offers clinically acceptable bond strength and can thus be used as a routine adhesive for orthodontic purposes since it is less likely to damage the enamel.

Evaluation of the effects of three different mouthwashes on the force decay of orthodontic chains.

BACKGROUND: Elastomeric chains are commonly used in orthodontics. Force decay in these materials poses clinical problems. The aim of this study was to evaluate the effects of three different mouthwashes on the force decay of orthodontic chains. MATERIALS AND METHODS: In this experimental study, elastomeric chains with two different configurations were divided into eight groups (two control and six test groups). After 10 s of prestretching up to 100% of their initial length, the chains were stretched for 25 mm on jig pins and then immersed in artificial saliva, persica, chlorhexidine 0.2% and sodium fluoride 0.05% mouthwashes. Ten cycles of thermocycling between 5°C and 55°C were conducted daily during the test period. In order to reach a 200-g initial force, seven loop closed chains, and five-loop short chains were selected. Forces were recorded by digital force gauge (Lutron) at initial, 24 h, 1, 2, 3 and 4 weeks for all groups. The amount of force loss was compared among different mouthwashes and times using one-way analysis of variance (post-hoc, Tukey, α = 0.05). RESULTS: About 20% of the force decay occurred during the first 24 h, but after that and up to the 4(th) week the rate of force loss was gradual and steady. After 4 weeks, persica and chlorhexidine caused the lowest and the highest percentage of force loss, respectively. These two mouthwashes showed statistically significant differences at all points of time (P < 0.05). CONCLUSION: Within the limitations of this study, during the orthodontic treatment, persica is preferred to chlorhexidine for oral health control.

Which Factors Affect Dental Esthetics and Smile Attractiveness in Orthodontically Treated Patients?

OBJECTIVES: This study aimed to find the factors that affect dental esthetics and smile attractiveness in orthodontically treated patients according to laypeople's judgment, and to determine whether there is any relationship between dental and smile esthetics. MATERIALS AND METHODS: Using the Q-sort technique, 60 laypersons (30 males, 30 females) rated dental and smile photographs of 48 orthodontically treated patients based on their degree of attractiveness. Dental and smile parameters of each rated image were measured by Smile Analyzer software. The Student's t-test and chi-square test were used to compare dental and smile parameters between attractive and unattractive images. The logistic regression was used to assess which variables predicted dental and smile esthetics in treated individuals. RESULTS: The philtral to commissural height ratio and gingival display were significantly different in attractive and unattractive smiles (P=0.003 and P=0.02, respectively). None of the dental variables were found to be a determinant of dental esthetics at the end of the orthodontic treatment (P>0.05). According to the judgment of all raters (female and male) and the male raters' judgment, smile attractiveness could be predicted by philtral to commissural height ratio and buccal corridor ratio (P<0.05). There was no statistically significant relationship between dental esthetics and smile attractiveness in orthodontically treated patients (P>0.05). CONCLUSION: The philtral to commissural height ratio and buccal corridor ratio can be considered as predictors of smile attractiveness in orthodontically treated patients. Achieving dental esthetics at the end of orthodontic treatment does not guarantee smile attractiveness.

Evaluation of some facial anthropometric parameters in an Iranian population: infancy through adolescence.

OBJECTIVES: By finding the mean value of anthropometric parameters in normal samples of a population, it is possible to create a template for facial analysis. The aim of our study was to measure the anthropometric parameters in 0- to 12-year-old girls of Fars ethnic origin in the Northeast of Iran. STUDY DESIGN: Six hundred sixty-two newborn to 12-year-old girls of Fars ethnic origin participated in the study. A digital camera was used to take frontal full-face photographs of each child. Thirteen measurements were taken with the Smile Analyzer software: al-al, ch-ch, en-en, ex-ex, ft'-ft', go'-go', t-t, zy'-zy', n'-gn', n'-sn, t-g', t-gn', t-sn. Data were analyzed using the SPSS software at the significance level of 0.05. RESULTS: In almost all parameters, we found significant growth acceleration between 2 and 4 years as well as 5 and 6 years of age. Another growth spurt was seen between 9 and 11 years, although it was less noticeable. Comparing the linear regression equations suggests that different craniofacial dimensions do not grow similarly. CONCLUSIONS: By age, craniofacial dimensions change at different rates. Different craniofacial dimensions do not grow at consistent rates. Some parts grow slower compared with others. The intercanthal width has the slowest growth. Facial height shows the fastest growth.

Evaluation of nasomaxillary growth of adolescent boys in northeastern Iran.

Anthropometry, a useful method for evaluating craniofacial soft tissues, makes the quantitative description of the face possible. It also assesses the degree of disharmony and imbalance in the growth and development of the face. The aim of this study was to examine the overall common age-related changes of nasomaxillary complex of adolescent boys in northeast Iran. Three- hundred- twelve 12 to 15 year-old boys voluntarily participated in this study. They were divided into three age groups (12-13, 13-14 and 14-15 year-old groups). Digital photographs of the subjects' faces were taken in Natural Head Position (NHP) frontal and profile views. After determination of the landmarks, nine anthropometric parameters including nasal length, mouth width, alar width, columella width, philtrum height, nasal width, nasolabial angle, nasal root slope angle and nasal index were measured by the Smile Analyzer software considering the magnification ratio of each image. One way ANOVA and Tukey test were used for statistical analyses. Significant differences between the three groups were detected in the mean alar, mouth and philtrum widths, nose length, nasolabial angle and nasal index (P<0.05). We did not find any significant differences in the mean nasal-root-slope angle and the mean philtrum height between the groups (P=0.29 and P=0.13, respectively). Aging of the facial profile is not a gradual process; it occurs in spurts and at different periods of life. During the studied time span, significant growth in nose width and nose length was obvious.

Esthetic preferences for the shape of anterior teeth in a posed smile.

INTRODUCTION: Although various aspects of smile esthetics have been considered in many studies, few of them have compared laypeople's preferences for an esthetic smile with regard to the shape of the anterior teeth. The aim of this study was to evaluate the effects of the shapes of the maxillary anterior teeth in men and women on the perception of an esthetic smile by different age and sex groups of laypeople. METHODS: Two pamphlets, each consisting of 9 smile images that differed only in the shapes of the canines and incisors, were shown to 4 groups of judges of different ages and sexes. They were asked to rank feminine and masculine smile images according to their preferences using a 10-cell linear horizontal visual analog scale. RESULTS: Neither in the men's nor in the women's pamphlets were there significant differences between the scores of the 4 groups of judges to the various tooth forms. In both pamphlets, regardless of canine shape, all groups of judges gave significantly different scores to square, square-round, and round incisors so that the median of scores for square incisors was significantly lower than those of the 2 other incisor forms. CONCLUSIONS: Sex and age of the laypersons did not affect their esthetic perception of the shapes of the maxillary anterior teeth. Incisor shape was the key determinant of their esthetic preferences; round incisors were the most esthetic. It is recommended to improve smile esthetics by mildly rounding the mesial and distal corners of square incisors.

Lip-tooth relationships during smiling and speech: an evaluation of different malocclusion types.

BACKGROUND: Few studies have focused on the impact of malocclusion on lip - tooth relationships during smiling and speech. AIM: To evaluate the impact of different malocclusions on lip - tooth relationships during smiling and speech, using video images. METHODS: One hundred and three subjects with Class I (N = 31), Class II division 1 (N = 26), Class II division 2 (N = 16) and Class III malocclusions (N = 30) were asked to repeat the same sentence and then smile in front of a video camera. Nine frames were extracted from each subject's video clip: at rest, posed smile, unposed smile and during the pronunciation of the sounds: 'che', 'fa', 'se', 'chee', 'tee' and 'mee'. On each frame, up to 10 parameters describing the lip - tooth relationships were measured. RESULTS: In all frames, there were no statistically significant differences in the upper central incisor display ratios among the malocclusion groups (p > 0.05). The buccal corridor ratio in the posed and unposed smiles did not differ significantly among the malocclusions (p > 0.05). The most frequently visible last maxillary tooth was the first premolar in the posed smile, and the second premolar in the unposed smile. In each malocclusion group, the upper central incisor display ratio varied significantly among the nine frames and the buccal corridor ratio during the unposed smile was less than the ratio during the posed smile; although this was only significant in the Class II division 2 subjects. The smile arc was similar in all malocclusions. CONCLUSIONS: In each malocclusion the upper central incisor display ratio varied significantly among the nine frames. In each group, the buccal corridor ratio during the unposed smile was less than that during the posed smile, but only the Class II division 2 group was significantly different. The smile arc did not differ among the malocclusions.

Retrospective evaluation of facial soft tissue cephalometric parameters in adolescents with normal occlusion.

Facial soft tissue cephalometric parameters are specific to each society. These measurements should be considered during planning treatment for orthodontic patients. We establish lateral cephalometric facial soft tissue norms in adolescent boys and girls with normal occlusion in Mashhad in the northeast of Iran, and compare them with those of other societies.

In vitro comparative study of conventional radiography and Root ZX apex locator in determining root canal working length.

Success in endodontic treatment depends on various factors. One of the most important is appropriate preparation of the root canal system, in addition to keeping the periapical region intact as much as possible. This is achieved by determining the penetration depth of the instruments into the canal or the "working" length. Several methods are introduced for working-length determination. The most popular techniques are radiography and electronic apex locators. One type of apex locator is the Root ZX. The purpose of this study was to compare the accuracy of the Root ZX in vitro with conventional radiography.

The effects of bracket removal on enamel.

BACKGROUND: Enamel cracks, which may develop during debonding orthodontic brackets, may jeopardise the integrity of the enamel and detract from the appearance of the teeth. AIM: To compare the adhesive remnant scores (ARI), the number, lengths and directions of enamel cracks before bonding and after debonding metal orthodontic brackets with three different methods. METHODS: Metal brackets were bonded with a self-curing orthodontic adhesive to the buccal surfaces of 75 recently extracted upper and lower premolars. The teeth were randomly divided into three groups, and the brackets removed either with a side-cutter, a single-blade bracket remover or a two-blade bracket remover. The number, directions and lengths of the enamel cracks before bonding and after debonding were compared. The number of 'pronounced' cracks (i.e. cracks that could be identified with the naked eye) and the ARI scores in each group were also compared. RESULTS: After debonding, the number of enamel cracks and pronounced cracks, and the lengths of the enamel cracks increased in all groups (p < 0.001). There were no statistically significant differences between the groups. The ARI scores and the direction of propagation of the enamel cracks were not influenced by the debonding method used (p = 0.73). CONCLUSIONS: Concerns about the enamel damage caused by the three methods of debonding justify caution. Despite widespread use of these methods, it would be sensible to search for methods that result in less enamel damage.