Association between sella turcica bridging and the impaction severity of palatally displaced canines: A retrospective study.

INTRODUCTION: This retrospective study aimed to investigate the association between the extent of the bridging and dimensions of sella turcica and the impaction severity of palatally displaced canines. Secondarily, any possible association between skeletal age and gender was evaluated. METHODS: Panoramic and cephalometric radiographs of 94 patients (63 female, 31 male; 19 pre-peak, 75 post-peak) with palatally displaced canines were evaluated. Sector classification and α angle were used to determine the impaction severity of palatally displaced canines on panoramic radiographs. The distance from the cusp tip of the palatally displaced canines to the occlusal plane (d) and the extent of the bridging and dimensions of the sella turcica were evaluated on cephalometric radiographs. RESULTS: Sella turcica bridging and dimensions did not vary regarding the impaction severity of palatally displaced canines, but a significant association was found between sella turcica bridging and skeletal age (P = 0.038). Class II (33.3%) and Class III (12.0%) bridging was higher in postpubertal patients. No differences between females and males were detected for the extent of bridging and dimensions of the sella turcica. CONCLUSIONS: These findings indicate no association between sella turcica bridging and dimensions and the impaction severity of palatally displaced canines. Sella turcica bridging is more frequent in the postpubertal period, whereas gender does not influence sella turcica bridging. More studies are needed to evaluate if the extent of sella turcica bridging may be indicative of severely impacted palatal canines, which in turn would allow for careful monitoring of patients from an early age and for the clinician to take preventive measures.

Influence of lateral cephalometric radiographs on extraction decision in skeletal class I patients.

BACKGROUND: Radiographic examination is considered 'justified' only when detection of a condition that would change the mechanisms and timing of treatment is possible. Radiographic safety guidelines have restricted the indication of lateral cephalometric radiographs (LCRs) to presence of distinct skeletal Class II or Class III. However, they are taken routinely in clinical practice and considered to be part of the 'gold' standard for orthodontic diagnosis. Therefore, the aim of this study was to test the null hypothesis that lateral cephalometric radiograph (LCR) evaluation would not alter the extraction/non-extraction decision in orthodontic treatment planning of skeletal Class I patients. MATERIALS AND METHODS: Intraoral and extraoral photographs, dental casts and extraoral radiographs of 60 skeletal Class I patients were prepared digitally for assessment using a presentation software. One experienced (EO) and inexperienced orthodontist (IO) was asked to decide on extraction or non-extraction on a Likert-type linear scale for treatment planning. This procedure was repeated 4 weeks later with a mixed order of patients and the LCRs being omitted. Kappa, Weighted Kappa (WK) and McNemar scores were computed to test decision consistency and Bland-Altman plots together with 95% limits of agreement were used to determine measurement accuracy and presence of systematic bias. RESULTS: Both EO (WK = 0.67) and IO (WK = 0.64) had good level of decision agreement with and without LCR evaluation. EO did not present a shift towards extraction nor non-extraction with LCR evaluation (McNemar = 0.999) whereas IO showed a tendency to extraction (McNemar = 0.07) with LCR data. Including LCR evaluation created a systematic inconsistency between EO and IO (Line of equality = 0.8, Confidence interval = 0.307-0.707). CONCLUSIONS: Lateral cephalometric radiograph evaluation did not influence the extraction decision in treatment planning of skeletal Class I patients. Reconsidering the necessity of lateral cephalograms in orthodontic treatment of skeletal Class I patients may reduce the amount of ionizing radiation. Key words: Lateral cephalometric radiograph, extraction, treatment planning, skeletal Class I.

Do long-term changes in relative maxillary arch width affect buccal-corridor ratios in extraction and nonextraction treatment?

INTRODUCTION: Our aims were to evaluate long-term maxillary arch width changes in orthodontic patients treated with and without premolar extractions and to provide a potential link to the buccal-corridor ratios. METHODS: Dental casts of 34 extraction and 32 nonextraction orthodontic patients with Class I malocclusions were digitized and evaluated before treatment (T1), at posttreatment (T2), and at postretention (T3). The mean postretention times for the extraction and the nonextraction groups were 5 years 2 months and 4 years 10 months, respectively. Specific arch width measurements were made on the anatomic y-axis of the casts between the most labial aspects of the anatomic dental arch immediately distal to the incisive papilla, the farthest point posteriorly of the conjunction of the third lateral and medial rugae on the midpalatal raphe and at an individually constant distance from the incisive papilla. Arch width changes were calculated and compared statistically to determine whether the dental arches were narrower after extraction treatment and at postretention. RESULTS: All maxillary arch width measurements remained virtually stable after extraction therapy and at the postretention follow-up. Significant increases were recorded for all maxillary arch width measurements in the nonextraction group after treatment (mean changes, 1.37-2.05 mm). Posterior arch width measurements decreased significantly between T2 and T3 (mean change, 0.5 mm). Mean changes between T1 and T2 were significant between the 2 groups for all measurements (P <0.05). Only the mean change in posterior arch width was significant between the 2 groups in the postretention period (P <0.05). CONCLUSIONS: Extraction treatment did not result in narrower maxillary dental arches, whereas nonextraction treatment slightly expanded the dental arch.

Osseointegrated implants with pendulum springs for maxillary molar distalization: a cephalometric study.

INTRODUCTION: Maxillary molar distalization is a common treatment approach for patients with Class II malocclusions who do not require extractions. Despite the many advantages of pendulum appliances, the maxillary incisors and premolars tend to shift mesially as the maxillary molars move distally. The purpose of this study was to investigate anchorage loss in patients treated with palatal osseointegrated implants combined with pendulum springs. METHODS: Pretreatment and posttreatment lateral cephalometric films of 30 consecutively treated patients were examined. One group (n = 15) had been treated with conventional pendulum appliances, and the other group (n = 15) was treated with palatal osseointegrated implants combined with pendulum springs. RESULTS: In the pendulum group, significant distal tipping of the maxillary first molars and mesial tipping of the maxillary premolars were noted. Distalization of the maxillary first molars, mesialization of the maxillary first premolars, and proclination of the maxillary left central incisor were significant in the linear measurements. In the implant group, the distal tipping of the maxillary first molars and first premolars and the increases in SNGoGn, FMA, Na Me, and Na ANS were significant. Intergroup comparisons showed that changes in the maxillary first premolars, maxillary central incisors, and vertical measurements were significant. CONCLUSIONS: The use of palatal osseointegrated implants is reliable and provides absolute anchorage.

Bolton tooth size discrepancies in skeletal Class I individuals presenting with different dental angle classifications.

The objective of this study was to investigate the frequency and association of Bolton tooth size discrepancies with dental discrepancies. Forty-eight skeletal Class I, 60 Class II, and 44 Class III subjects with similar skeletal characteristics were included in this study. Analysis of variance was performed to compare the mean ratios of Bolton analysis as a function of the Angle classification and sex. To determine the prevalence of tooth size imbalances among the three groups of occlusions and the two sexes, chi-square tests were performed. To determine the correlation of tooth size imbalances with certain dental characteristics, Pearson's correlation coefficients were calculated. No statistically significant differences were determined for the prevalence of tooth size discrepancies and the mean values of Bolton's anterior and overall ratios among the occlusal groups and sexes. Bolton's anterior ratio discrepancies had significant correlations with midline shifts (P < .05) in Angle Class I cases, with U1-SN angle (P < .01) in Angle Class II cases, and with L1-APog distance (P < .05) in Angle Class III cases. Bolton discrepancies related to overall ratio had significant correlations with overjet (P < .05) in Class I cases, with overbite (P < .05) and U1-SN angle (P < .01) in Class II cases, and with IMPA (P < .01) in Class III cases. A high prevalence of tooth size discrepancies in an orthodontic patient population and the statistically significant correlation of some of these with some dental characteristics suggest that the measurement of interarch tooth size ratios might be clinically beneficial for treatment outcomes.

Perception of pain during orthodontic treatment with fixed appliances.

The aims of this study were to investigate the initial time at which pain occurs after insertion of two initial wires of different sizes, the duration of the pain, the areas affected within the mouth, the level of self-medication, the effect of this pain on daily life, and whether gender is important in the perception of pain. The study group consisted of 109 patients (52 boys, 57 girls) with a mean chronological age of 13.6 years for boys and 14.7 years for girls. Insertion of either a 0.014 or 0.016 inch wire was by random selection. Following insertion of the archwires, a questionnaire comprising a total of 49 questions was given to the patients. They described the time of initial pain in the first question, answered the next 24 questions as 'yes' or 'no', and used a visual analogue scale for the final 24 questions. No significant differences were found in terms of gender, in the perception period of initial pain as regards the areas affected within the mouth or the effect of pain on daily living when the 0.014 and 0.016 inch wire groups were compared at 6 hours, 1, 2, 3, 4, 5, 6 and 7 days. At 24 hours, which was found to be statistically significant, more pain relief was used in the 0.014 inch archwire group. The results show that in both groups, initial pain was perceived at 2 hours, peaked at 24 hours and had decreased by day 3.

Evaluation of the position of the hyoid bone in relation to vertical facial development.

Evaluation of the position of the hyoid bone in relation to vertical facial development and comparative evaluation of the relation of this position with the dentofacial system was made on 25 patients with hyperdivergent vertical growth, 25 patients with hypodivergent vertical growth, and 25 patients with normal vertical facial development. SN-Go-Gn, Gonion, ANS-PNS/Go-Gn angles and S-Go, N-Me, S-Go/N-Me measurements from lateral cephalometric films were used as identification parameters. Seven horizontal, five vertical and five angular cephalometric measurements were made in order to determine the position of the hyoid bone. SN plane was used as the reference plane. Results were evaluated through "t" test. No significant relation was found between hyoid bone position and gender. When gender distinction was disregarded, and the group with normal facial development was compared with the hyperdivergent group, statistically significant differences were observed for CVT-H distance in horizontal measurements and for H-SN, H-F, H-PD, H-OD distances in vertical measurements. When the group with normal facial development was compared with the hypodivergent group, only the horizontal measurement Pg-H was statistically significant. The hyoid bone location in the hyperdivergent group was in a more of a posterior and superior position. The hyoid bone location in the hypodivergent group was not changed vertically, however, it had more of a posterior placement with the increase of Pg-H distance.

Scanning electron microscope study of the effects of soft drinks on etched and sealed enamel.

The purpose of this study was to determine the effects of cola and other acidic drinks on etched tooth enamel in a simulated oral environment. The test beverages were cola, orange soda, lemon soda, and sparkling mineral water. Sixty extracted premolars were divided into an experimental group (n = 40) and a control group (n = 20). Half of the buccal surface of each tooth in the experimental group was coated with wax. The teeth were etched for 60 seconds with 37% phosphoric acid, and half of the teeth were also bonded. The experimental group was further divided into 4 subgroups of 5 teeth each, and each subgroup was exposed to 1 of the test beverages in a thermocycling apparatus. The apparatus was designed to keep the teeth in artificial saliva for 2 hours and in the soft drink at room temperature for 15 minutes. This procedure was performed 3 times a day for 5 days. The control group was also divided into 4 subgroups of 5 teeth each. Half of the buccal surface of each tooth in 2 subgroups was coated with wax, and the teeth in the other 2 were left uncoated. One waxed and 1 unwaxed subgroup were then etched, and the other waxed and unwaxed subgroups were etched and bonded. The waxed subgroups were stored in artificial saliva for 5 days, and the unwaxed subgroups were examined without further exposure to liquids. Surfaces exposed to acidic soft drinks were compared with control surfaces under a scanning electron microscope. Defect zone borders were observed between the exposed areas and the wax-coated areas of teeth in the experimental groups, especially the subgroups exposed to cola, orange soda, and lime soda. Fewer defect zones were observed on teeth exposed to sparkling mineral water. The results indicate that acidic soft drinks cause enamel demineralization on etched tooth surfaces.

A comparison between zinc polycarboxylate and glass ionomer cement in the orthodontic band cementation.

Fixed orthodontic appliances have been held responsible for demineralization and caries since the time they were first introduced. Zinc polycarboxylate and glass ionomer cements are the primary materials used in band cementing. In this study, we evaluated the re-cementing frequencies, enamel demineralization and the degree of cement remains of the bands cemented with glass ionomer and zinc polycarboxylate cements. We have concluded that given the retentive properties and enamel decalcification degree, the glass ionomer cements are to be preferred by the orthodontist.