The Asymmetry of the Mandible in Patients with Unilateral Temporomandibular Joint Disc Displacement Confirmed by Magnetic Resonance Imaging.

Objectives: The study aimed to determine the relationship between the mandibular asymmetry index according to Kjellberg between patients with painful unilateral anterior disc displacement (DD) and asymptomatic volunteers without disc displacement. Vertical measurements were performed on a panoramic single-image radiograph, and the disc status was confirmed by magnetic resonance imaging (MRI). Material and methods: Two groups of subjects were retrospectively selected, 40 patients (the overall mean age was 35.5 years; 75% female) with temporomandibular disorder symptoms confirmed by RDC/TMD axis I and manual functional analysis. Unilateral DD was determined by MRI. A comparative group of asymptomatic volunteers (20 dental students with a mean age of 23.4 years; 72% female) had the physiological position of the disc determined by MRI. The vertical asymmetry of the condyle was determined by the method of Kjellberg et al. The symmetry of the gonial angle of the mandible was also measured. Results: A comparison of the mean of the asymmetry index between patients (average 90.89±7.08%) and asymptomatic volunteers (mean 95.86±4.44%) showed a statistically significant difference (p=0.0029). There was no difference (p=0.088) in gonial angle symmetry between the patients (mean 96.48±2.96°) and the asymptomatic volunteers (mean 97.52±2.31°). The distribution of the presence of individual DD diagnoses (partial and total displacement with reduction, displacement without reduction) in patients diagnosed with asymmetry of the mandible was without statistical significance (p>0.05). Conclusion: This study actually points to the asymmetry of the mandible as a potential morphological risk of anterior DD.

Canine Crown Sexual Dimorphism in a Sample of the Modern Croatian Population.

Sex assessment is a key part of forensic analysis to establish the identity of unknown deceased individuals. Previous studies have shown that canines are the most dimorphic teeth, but population-specific data are necessary for forensic methods. This study explores sex dimorphism in canine crown dimensions and morphology in a contemporary Croatian population. The material consisted of 302 dental casts (147 females, 155 males) of orthodontic patients and dental students (11-25 years). The distal accessory ridge (DAR) of the upper and lower canines was evaluated using the Arizona State University Dental Anthropology System. Mesiodistal (MD) and buccolingual (BL) crown dimensions were measured on 120 casts. Sex differences in MD and BL dimensions were significant (p < 0.05) for all the canines (upper and lower, left and right), while in DAR only for lower canines (p < 0.000001). When all variables were put into the model, backward stepwise discriminant function analysis isolated lower canine DAR and lower left canine MD as the two independent variables differentiating sex. Using these two variables, a discriminant function formula allowed for sex determination with an accuracy of 73.5%. This study shows that both canine crown morphology and dimensions are useful for sex determination, especially for lower canines. These methods can be applied to children, as lower canines erupt at about 9 years of age.

Artificial neural network model for predicting sex using dental and orthodontic measurements.

Objective: To investigate sex-specific correlations between the dimensions of permanent canines and the anterior Bolton ratio and to construct a statistical model capable of identifying the sex of an unknown subject. Methods: Odontometric data were collected from 121 plaster study models derived from Caucasian orthodontic patients aged 12-17 years at the pretreatment stage by measuring the dimensions of the permanent canines and Bolton's anterior ratio. Sixteen variables were collected for each subject: 12 dimensions of the permanent canines, sex, age, anterior Bolton ratio, and Angle's classification. Data were analyzed using inferential statistics, principal component analysis, and artificial neural network modeling. Results: Sex-specific differences were identified in all odontometric variables, and an artificial neural network model was prepared that used odontometric variables for predicting the sex of the participants with an accuracy of > 80%. This model can be applied for forensic purposes, and its accuracy can be further improved by adding data collected from new subjects or adding new variables for existing subjects. The improvement in the accuracy of the model was demonstrated by an increase in the percentage of accurate predictions from 72.0-78.1% to 77.8-85.7% after the anterior Bolton ratio and age were added. Conclusions: The described artificial neural network model combines forensic dentistry and orthodontics to improve subject recognition by expanding the initial space of odontometric variables and adding orthodontic parameters.

Association between arch width changes and long-term stability 20 years after orthodontic treatment with and without extractions.

OBJECTIVES: To investigate long-term stability 20 years after orthodontic treatment and the association with arch width changes during treatment. MATERIALS AND METHODS: This retrospective study investigated 103 patients with Class I and II malocclusions treated with fixed appliances with and without extractions. The sample was treated by one experienced orthodontist and collected from a private orthodontic office. Dental casts were obtained pretreatment (T1), posttreatment (T2), and long-term postretention (T3); they were scanned and converted to STL files. Measurements were evaluated in for the upper and lower arch: intercanine width (IC), intermolar (IM) width, Little's irregularity index (LII). RESULTS: There were 73 female and 30 male patients. Class I was present in 74 patients and Class II in 29. Average postretention time was 17.2 (±6.5) years after an average active retention time of 3.4 (±1.17) years. Extraction was performed in 55 patients while 48 received nonextraction treatment. Bonferroni Post Hoc test showed that LII in the upper and lower arches at T1 was significantly higher in the extraction group (P < .001). Upper and lower arch LII at T3 was slightly higher in extraction cases but remained under 2.05 mm. LII at T3 in the upper and lower arches showed negative correlation with IM T3 in the upper arch (Pearson, N = 103, P = .047), while IC in the upper and lower arches at T3 correlated with IM T3 in the upper and lower (N = 103, P < .001). CONCLUSIONS: Clinically relevant long-term stability in both arches was found in extraction and nonextraction cases. Intermolar width and its change during orthodontic treatment was an influential factor on long-term stability in extraction cases.

The Cameriere, Haavikko, Demirjian, and Willems methods for the assessment of dental age in Croatian children.

AIM: This study aimed to evaluate the accuracy and precision of the Cameriere European formula, Demirjian, Haavikko, and Willems methods for estimating dental age in a sample of children with permanent dentition in Croatia. MATERIAL AND METHODS: The study consisted of a sample of 1576 panoramic radiographs; a sub-sample of 84 OPGs, in which all first seven mandibular teeth were maturated, was excluded from the study. A final sample of 1492 (704 males and 788 females) aged 6.0 to 13.9 years was evaluated. Seven mandibular teeth from the left side of the mandible were analyzed, and dental age (DA) was determined by the Cameriere European formula, Demirjian method from 1976, Haavikko, and Willems methods and compared to chronological age (CA). In addition, the mean age difference (DA-CA), the mean absolute error (MAE) between dental and chronological age, the percentage of the individuals of dental age within ± 0.25 to ± 2 years of chronological age, and intra-observer and inter-observer statistics were calculated. RESULTS: The Cameriere European formula estimated the best dental age compared to the chronological age; the mean underestimation was - 0.4 years for both sexes, Haavikko underestimated by - 0.17 years, while Demirjian and Willems overestimated by 1.02 years and 0.48 years, respectively. The most significant difference showed the Demirjian method in 11-year-old and 12-year-old females. The MAE were 0.50 years, 1.01 years, 0.61 years, and 0.78 years in males and 0.51 years, 1.18 years, 0.61 years, and 0.70 years in females for the Cameriere European formula, Haavikko, Willems, and Demirjian methods, respectively. Furthermore, the Cameriere European formula showed the highest proportions of individuals with DA within ± 0.5 year difference of the CA, 61.5% in males and 59.6% in females. In addition, the Cameriere method showed the best intra-observer and inter-observer agreements. CONCLUSIONS: Although the Demirjian method was used previously in Croatian children for legal, medical, and clinical purposes, the Cameriere European formula, Haavikko, and Willems were more accurate in the tested sample. According to our findings, the Cameriere European formula showed the best accuracy and precision in dental age assessment in Croatian children following Haavikko, and we recommend it as the method of the first choice in forensic and clinical analyses.

Impact of Gingival Margin Asymmetries on the Smile Esthetic Perception of Dental Specialists, Doctors of Dental Medicine, Students, and Laypeople: a Comparative Pilot Study.

Objective: To evaluate the perceptions of altered incisor gingival position among dental specialists, dentists, dental students, and laypeople. Materials and methods: Four digital smile photographs with altered gingival margin position of the right maxillary incisor (0, 1, 2, and 3 mm) were presented to a sample of 232 respondents (71.1% female; 28.9% male): 42 dental specialists, 63 dentists, 33 dental students (1st to 3rd year), 38 dental students (4th to 6th year) and 56 laypeople. The questionnaire consisted of four randomly displayed photographs, administered via Google Form, and respondents were asked to rate the images on a scale from 1 to 5, from the least attractive to the most attractive. A statistical analysis was performed using the TIBCO Statistica program (v. 13.3. 0, TIBCO Software Inc., Palo Alto, CA, USA; 2017). According to the Shapiro- Wilk's test, the data were not distributed normally. The Kruskal-Wallis test with post hoc multiple comparisons with the Bonferroni adjustment were used to compare group esthetic scores and to determine the threshold levels of deviation at which each group was discriminated between esthetic and non-esthetic situations. Results: Median values of esthetic scores decreased in all groups as the gingival asymmetries increased. Dental professionals were significantly more critical of esthetics than laypeople in all levels of asymmetry. The greatest difference was found for 2 mm of gingival asymmetry (p=0.002). Conclusion: From the results of our study, we can conclude that the perception of gingival asymmetries in the esthetic zone of smile differs among dental specialists, doctors, students, and laypeople. Dental specialists, doctors, and clinical students were more critical of these asymmetries, while preclinical students and laypeople noticed only 2 mm or more of gingival asymmetry of central incisors.

Dental and Skeletal Age in Patients with Palatally Displaced Canines.

Objective: To determine potential associations between dental and skeletal maturation and palatally displaced canines (PDC) considering gender and chronological age. Material and methods: This study included pretreatment panoramic and lateral cephalometric radiographs of 43 subjects with PDCs and 203 randomly selected orthodontic subjects with normally erupted canines. Both groups were non syndromic patients. Chronological age of subjects was rounded and noted in years with decimal points and compared with chronological age according to Demirjian's dental age assessment. Skeletal maturation was determined by cervical vertebrae changes on cephalometric radiographs. Results: Female subjects with PDC were more affected by left side canine displacement than males (p=0.027) with five times higher odds ratio (OR = 4.9; 95% CIL=1.2-19.7). A comparison of chronologic and skeletal age indicated that PDC subjects were skeletally younger than unaffected groups with statistically significant differences at the age of 10, 12 and 13. (p=0.05). Conclusion: Young subjects with PDCs showed skeletal maturation delay compared to control group, indicating that skeletal maturation assessment could be one of unexplored predicting factors of a PDC, especially at the age between 10 and 13 years in both genders. Subjects with PDC showed intensive growth spurt after the age of 12 years in females, and after the age of 13 in males. Dental maturation delay showed no statistical significance in PDC prediction.

EVAULATION OF BLINK REFLEX BETWEEN PATIENTS WITH IDIOPATHIC TRIGEMINAL NEURALGIA AND HEALTHY VOLUNTEERS.

The purpose of the study was to find differences in the parameters of the response to the blink reflex (BR) between patients with idiopathic trigeminal neuralgia (TN) and health volunteers. A prospective cohort study was conducted over 2 years. The TN-subgroup included 15 patients (mean age / SD 62.3 ± 10.7 years). Pain-free and healthy volunteers as a HV-subgroup (mean age / SD: 30.8 ± 8.1 years) were recruited from asymptomatic students of dental medicine. Diagnostic parameters were determined by measuring latency to the onset of the BR components from electric stimulation. The following branches of the trigeminal nerve were affected: maxillary branch only (26.7%), mandibular branch only (20%), combined: ophthalmic branch with maxillary branch (6.7%), and ophthalmic branch with mandibular branch (6.7%) respectively, combined maxillary and mandibular branch (26.7%) and affected all three branches (13.4%). The latencies of the BR, left and right side together, between subgroups were significantly higher for values R1 (homolateral early response), R2 (homolateral late response), R2c latency (contralaterally expressed response) in the TN-subgroup (p < 0.05). On the basis of the presence of R1c and R3 latencies and upon considering the abnormal findings of the BR, no statistically significant differences were found between the examined subgroups (p > 0.05). Blink-reflex parameters (R1, R2 and R2c) were significantly abnormal comparing TN-patients with healthy volunteers. The R3 component of the BR was related to noxious stimuli, likewise by innocuous stimuli.

Skeletal Maturation in Different Vertical Facial Growth Pattern.

OBJECTIVE: To assess whether there are differences in skeletal maturation among subjects with horizontal, vertical, and neutral facial growth patterns. MATERIAL AND METHODS: The study was performed on 48 latero-lateral craniographs of patients with horizontal, 48 with vertical and 50 with neutral growth patterns aged 12 to 18 years. Eight variables from the Zagreb 82 MOD, Bracchetti and Accord analysis, were selected for measuring angular and linear parameters on latero-lateral craniographs. The assessment of skeletal maturation was done by using the CVMS method. RESULTS: Statistical analysis showed significant differences in skeletal maturity (p <0.001) between subjects with horizontal and vertical growth pattern and between the subjects with neutral and vertical growth pattern (p <0.05), while no significant difference was found between patients with horizontal and neutral growth pattern. In the younger group (12 - 15 years) there was a statistically significant difference (p <0.05) among subjects with horizontal and vertical growth patterns. In the older group (16 - 18 yrs) there was a statistically significant difference (p > 0.05) in skeletal maturity among subjects with vertical growth patterns compared with horizontal and neutral. In terms of stages of skeletal maturity, patients with a horizontal and neutral growth pattern in the younger group were on average in the fourth stage, and those with a vertical growth pattern in the third stage. In the older group, patients with a horizontal and neutral growth pattern were on average in the fifth stage of skeletal maturity and those with a vertical growth pattern in the fourth stage. CONCLUSION: According to the growth pattern, patients differ in the stage of skeletal maturity.

Alcohol Abuse in the Dental Patient and Temporomandibular Disorder Caused by Trauma.

The aim of the paper was to describe the multidimensional character of alcoholism and its effects on oral health, with a review of the relation between the traumatogenic factor of temporomandibular disorders (TMDs) and bruxism development. The difference between moderate drinking and the development of alcohol addiction which leads to alcoholism-related medical, social, legal and economic issues is not always clear. Alcoholism is often hidden within the private and wider social framework of a patient. Oral diseases are easy to notice in recorded alcoholics as well as in, for example, smokers. TMDs consist of a disorder of masticatory muscles and/or a disorder of temporomandibular joint (TMJ). Since the traumatogenic factor of individuals under the influence of alcohol is clearly evident, it can potentially become an initializing factor of TMJ disorder's clinical signs and symptoms development. A modern approach to the etiopathogenesis is to include the multifactorial model, that is, combinations of potential factors with various individual importances. In everyday dental practice, co-morbidities of oral diseases and alcoholism are expected more often, as well as oral diseases with their etiopathogenesis partially related to alcohol use.

Oral Hygiene Behavior of Croatian Adolescents during Fixed Orthodontic Treatment: A Cross-sectional Study.

OBJECTIVE: To investigate the impact of fixed orthodontic treatment on adolescents' oral hygiene behavior and to examine their food consuption during fixed orthodontic treatment, as well as their motivation to maintain oral hygiene. MATERIALS AND METHODS: This research was carried out in a form of a survey questionnaire consisting of 23 questions. The sample comprised 170 adolescent patients aged from 11 to 19 who underwent the fixed orthodontic treatment at the Orthodontic Clinic of the Zagreb University Hospital Centre. RESULTS: The orthodontic appliance did not interfere with the patients' maintenance of oral hygiene, but it made the consumption of certain foods more difficult. Most adolescents brushed their teeth twice a day, using medium-soft brushes (35%). Regarding additional oral hygiene aids, 72.4% of the respondents used interdental brushes, more than 50% of the respondents used antiseptic mouthwashes for mouth rinsing, whereas only 31.2% of the tested population used dental floss (4.1% of which daily). The respondents were highly motivated to maintain oral hygiene by their orthodontists (96.5%), but only a small number of the respondents were informed about the importance of an adequate diet while undergoing a fixed orthodontic treatment. CONCLUSION: Orthodontists should provide their patients with detailed instructions on hygiene maintenance and adequate diet during orthodontic treatment to minimize negative side effects of the fixed orthodontic treatment. Patients should be motivated upon each follow-up examination and encouraged to use as many oral hygiene aids in their daily routines as possible.

Validity and reliability of the Psychosocial Impact of Dental Aesthetics Questionnaire in Kosovar adolescents.

OBJECTIVE: To test the validity and reliability of the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ)-Albanian version in Kosovar adolescents and assess gender-based differences of malocclusion on PIDAQ subscales. METHODS: A sample of 200 adolescents aged 12-15 years were evaluated for orthodontic treatment need by a previous calibrated dental examiner, using the aesthetic component (AC) of the Index of Orthodontic Treatment Need-Aesthetic Concern (IOTN-AC) and the dental aesthetic index (DAI). Internal consistency, test-retest reliability, discriminant validity and gender-based impact of malocclusion on psychosocial impact was assessed. RESULTS: The Albanian version of the PIDAQ shows satisfactory internal consistency (α ranging from 0.73 to 0.90) with high test-retest reliability (r > 0.83). The discriminant validity revealed that subjects with minor and severe malocclusion according to dichotomous DAI categorization had different PIDAQ scores. No significant gender-based differences were noted on the impact of malocclusion on psychological and social aspect or Dental Self-confidence (DSC); however, significant gender-based difference was noted on the impact of malocclusion on AC. CONCLUSION: The Albanian version of the PIDAQ demonstrated good psychometric properties and applicability to this age group in Kosova.

OROFACIAL PAIN - DIAGNOSTIC AND THERAPEUTIC CHALLENGES.

The concept of diagnostics and therapy of musculoskeletal and neuropathic diseases of the stomatognathic system, which are the subject of this paper, has been developing for decades. It can be said that in order to avoid misunderstanding, the orofacial pain as a clinical problem, in the narrower sense, involves non-odontogenic and non-malignant causes of orofacial region. In this study, the results of clinical diagnosis of the population of 557 consecutive patients with orofacial pain based on multidisciplinary diagnostics were evaluated. 15.6% of patients have given up on the participation in the study. It has been shown that the patients who dropped out of the study were significantly older (p=0.0411) than those who agreed to participate, but there was no difference in gender ratio (p=0.185) since the proportion of female patients prevailed. In an analysis of 84.4% of patients participating in the study, the elevated anxiety values were established (mean value on STAI 1 was 39.2 and STAI 2 was 41.1) and statistical significance was found in correlation between elevated anxiety and intensity of pain as shown on visual analogue scale on open mouth (p<0.0001). Compared to the age, the statistical significance was for STAI 1 (p=0.0097) but not for STAI 2 (p=0.5599). The most common form of therapy is Michigan stabilization splint: for disc displacement of temporomandibular joint (TMJ) in 38.9% of patients and in combination with physiotherapy in 18.7% of patients; for osteoarthritis of TMJ in 28.4% and in combination with physiotherapy in 26.4% of patients. The treatment with anticonvulsant drugs for trigeminal neuralgia predominates in 54.3% of patients, which is combined with acupuncture in 25.7% of patients and only acupuncture in 17.1% of patients. In this study, a multidisciplinary co-operation in initial diagnostics and differential was designed to develop subspecialist knowledge on orofacial pain.

Comparison of Shear Bond Strength Orthodontic Brackets Bonded to Zirconia and Lithium Disilicate Crowns.

AIM: of this study was to analyze Shear Bond Strength (SBS) and Adhesive Remnant Index (ARI) of ceramic and metallic orthodontic brackets bonded to zirconia or lithium-disilicate ceramics used for prosthetic restorations, conditioned with hydrofluoric acid (HFA) or phosphoric acid (PhA), as well as to determine the Porcelain Fracture Index (PFI), in order to examine the condition of the ceramic surface after debonding. MATERIAL AND METHODS: The research was conducted on 96 prepared all-ceramic samples divided into 8 groups combined from the type of ceramic material, orthodontic brackets, and surface conditioning. SBS was tested with Universal Testing Machine, and the samples were analyzed using a Scanning Electron Microscope, to determine ARI and PFI. Statistical data were processed using ANOVA, with the level of significance α = 0.05. RESULTS: Lithium-disilicate showed better bond strength in almost all groups. However, no significant difference between the groups was noticed and none of the factors had a significant influence on the mean values of SBS (p>0.05). Nevertheless, ARI significantly depended on the type of bracket (p = 0.005), and PFI significantly depended on the type of etchant (p = 0.029). CONCLUSION: The use of HFA for surface etching of zirconia and lithium-disilicate, does not cause a significant increase in the SBS values as compared to etching with PhA and silane application. Furthermore, HFA can weaken the surface structure of the ceramic, and considering its toxicity, might not be the best suitable conditioner prior to orthodontic bonding to lithium disilicate, and in particular to zirconia, also taking into account its crystalline structure.

Hypodontia, Gender-Based Differences and its Correlation with other Dental Clinical Features in Kosovar Adolescents.

AIM: The primary aim of this study was to evaluate the gender-based differences in patients with hypodontia. As a secondary outcome, the study looked into the correlation between hypodontia and other dental clinical features among Kosovar adolescents. MATERIAL AND METHODS: 3,306 students, aged between 15-21 years were examined in schools in Kosovo. Examinations were performed using a dental mirror to assess the number of teeth present, and dental impressions were taken from hypodontia subjects. Panoramic and periapical radiographs, as well as intraoral photographs, were taken in subjects who were suspected to have hypodontia to verify the diagnosis. RESULTS: 77 of the examined subjects had hypodontia, among which 46 were females (59.7%) and 31 were males (40.3%). The most frequently missing teeth were the maxillary lateral incisors, followed by the mandibular second premolars. 68 patients (88.3%) had at least one dental clinical feature concurrent with hypodontia. CONCLUSION: No significant difference was noted in the prevalence of hypodontia according to gender. Teeth rotation was the most commonly observed clinical feature followed by inclination.

Mesiodistal and Buccolingual Dimensions in Croatian Orthodontic Hypodontia Patients' Teeth.

OBJECTIVE: This study compared mesiodistal (MD) and buccolingual (BL) tooth dimensions of hypodontia patients with a control group with complete dentition. The null hypothesis was that there was no difference in tooth sizes between hypodontia patients and the controls. METHODS: The sample comprised 76 patients with hypodontia (50 female and 26 male) aged between 11 and 18 years. The control group comprised 50 females and 26 males with the same age range as the study group. Mesiodistal (MD) and buccolingual (BL) dimensions were measured on pretreatment dental casts with a digital caliper to the nearest 0.01 mm. The data were analyzed using Statistica 7.1 (StatSoft Inc.) statistical package (descriptive statistics, test of distribution normality, parametric statistics). RESULTS: The most common congenitally missing teeth were the lower second premolars (left 13.45% and right 13.90%) and upper lateral incisors (both left and right 12.56%), followed by upper second premolars (right 9.4o% and left 10.31%). The greatest differences between the study and control group were found in upper lateral incisors, 8.08% in MD and 6.40% in BL dimension. The smallest difference was found in BL dimension of lower lateral incisor (2.37%), MD dimension of lower second premolars and upper first molar (2.61%) and MD dimension of lower central incisor (2.26%). CONCLUSION: The teeth are smaller in subjects with hypodontia than those of the controls on average 4.02% in MD dimension and 3.85% in BL dimension. The tooth that showed the greatest difference in tooth dimension was maxillary lateral incisor.

Changes of bite force and occlusal contacts in the retention phase of orthodontic treatment: A controlled clinical trial.

INTRODUCTION: We aimed to determine whether appliance type affects changes in maximum voluntary bite force (MVBF) and the number of occlusal contacts (NOC) during retention, controlling for sex, age, and body mass index. METHODS: The sample comprised 176 examinees (70 male, 106 female) aged 14 to 20 years: 30 had maxillary and mandibular Essix retainers, 30 had wrap-around retainers, and 30 had a combination of fixed mandibular canine-to-canine retainers bonded on each tooth separately (double twisted, 0.254 mm in diameter, stainless steel ligature wire) and Essix retainer in the maxillary arch; 86 with normal occlusion were not treated. MVBF and the NOC were measured immediately after removal of preadjusted edgewise appliances (Roth prescription), 6 weeks after that, and after the next 4 weeks. RESULTS: Increases in MVBF and the NOC were demonstrated, but subjects with 2 Essix retainers showed lower values than did the others. Changes were related to type of appliance, sex, and age (P <0.05) but not to body mass index. The increase in NOC occurred faster than the increase of MVBF, more and sooner with the wrap-around retainer and in male subjects than with the Essix and in female subjects. MVBF and NOC nearly reached the values of the control subjects. CONCLUSIONS: Settling of the occlusion depends on appliance type: it takes longer in female patients and with Essix in both dental arches than with the other tested appliances.

Shear Bond Strength of Orthodontic Brackets Bonded to Zirconium Crowns.

BACKGROUND: An increasing demand for esthetic restorations has resulted in an increased use of all-ceramic restorations, such as zirconium. However, one of the challenges the orthodontist must be willing to face is how to increase bond strength between the brackets and various ceramic restorations.Bond strength can beaffected bybracket type, by the material that bracketsaremade of, and their base surface design or retention mode. ​: Aim: of this study was to perform a comparative analysis of the shear bond strength (SBS) of metallic and ceramic orthodontic brackets bonded to all-zirconium ceramic surfaces used for prosthetic restorations, and also to evaluate the fracture mode of these two types of orthodontic brackets. MATERIAL AND METHODS: Twenty samples/semi-crowns of all-zirconium ceramic, on which orthodontic brackets were bonded, 10 metallic and 10 ceramic polycrystalline brackets, were prepared for this research. SBS has been testedby Universal Testing Machine, with a load applied using a knife edged rod moving at a fixed rate of 1 mm/min, until failure occurred. The force required to debond the brackets was recorded in Newton, then SBS was calculated to MPa. In addition, the samples were analyzed using a digital camera magnifier to determine Adhesive Remnant Index (ARI). Statistical data were processed using t-test, and the level of significance was set at α = 0.05. RESULTS: Higher shear bond strength values were observed in metallic brackets bonded to zirconium crowns compared tothoseof ceramic brackets, with a significant difference. During the test, two of the ceramic brackets were partially or totally damaged. CONCLUSION: Metallic brackets, compared to ceramic polycrystalline brackets, seemed tocreate stronger adhesion with all-zirconium surfaces due to their better retention mode. Also, ceramic brackets showed higher fragility during debonding.

ASSOCIATION BETWEEN DENTAL AND SKELETAL MATURATION STAGES IN CROATIAN SUBJECTS.

This study investigated the relationships between the stages of calcification of teeth and cervical vertebral maturation. The sample consisted of 295 subjects (129 male and 166 female), mean age 13.36 ± 2.65 (range 7-18) years. Dental age was evaluated from panoramic radiographs according to the method of Demirjian. Cervical vertebral maturation was determined on lateral cephalometric radiographs using cervical vertebrae maturation stages (CVS). For assessing the relationship between cervical vertebral and dental maturation, percentage distributions of the stages of calcification for each studied tooth were calculated. Only in the first CVS stage, boys and girls were of the same age. In all other stages (CVS 2-CVS 6) girls were by 0.98 (range 0.23-1.86) younger than boys. Gender differences in the mineralization pattern were also observed. It was found that dental maturation was finished earlier in female subjects. The highest correlation coefficient between dental and skeletal maturity was found for second premolars. Mineralization pattern of second premolars could be considered as a guideline for prediction of the pubertal growth spurt. Dental maturation stages might be clinically useful as a reliable indicator of facial growth.

Antimicrobial effect of different brushing frequencies with fluoride toothpaste on Streptococcus mutans and Lactobacillus species in children with fixed orthodontic appliances.

OBJECTIVE: To evaluate the antimicrobial effect of different frequencies of brushing with fluoride toothpaste on the levels of salivary mutans streptococci and lactobacilli in children undergoing fixed orthodontic treatment. METHODS: The study included 22 patients scheduled for fixed orthodontic therapy distributed between 2 groups with different hygiene regimes. All the subjects received identical braces, bands, and brackets bonded with the same material. Stimulated saliva samples were obtained before placement of the appliance and at 6, 12, and 18 weeks during the therapy. Saliva samples were cultured on selective microbial agar for the detection of microorganisms. RESULTS: Salivary mutans streptococci were significantly suppressed throughout the experimental period in the group that brushed 4 times a day as compared to the group that brushed twice a day. Salivary lactobacilli were not significantly affected by the frequency of brushing with 0.32% sodium fluoride (NaF) toothpaste. CONCLUSIONS: The use of 0.32% NaF-containing toothpaste more than 3 times a day has effective antimicrobial activity on mutans streptococci but not lactobacilli in the saliva of children with fixed orthodontic appliances.