Evaluation of First Molar Buccolingual Angulations and Dental Arch Parameters in Adolescents with Bilateral Posterior Crossbite.

Objective: This study aimed to compare the maxillary and mandibular transverse dental arch widths and buccolingual inclinations of the molar teeth in patients with and without bilateral posterior crossbite (BPC) divided into different age groups. Methods: The study included dental models from 120 patients (age: 12-18 years), including 60 with BPC (32 boys and 28 girls) and 60 without BPC (controls; 30 boys and 30 girls), who were divided into three age groups (12-14, 14-16, and 16-18 years). The centroid and lingual transverse arch widths, dental arch perimeters, dental arch depths, and buccolingual angulation of the molar teeth in the maxillary and mandibular regions were evaluated using scanned three-dimensional dental models. Results: Dental arch parameters and buccolingual molar angulation did not significantly differ between the different age groups in either the patients with BPC or the controls (p>0.05). However, several dental arch width parameters differed significantly between sexes in both groups, with higher values in boys than in girls (p<0.05). The difference in the upper and lower molar buccolingual angulation between patients with BPC and controls was greater at the age of 16-18 years than the age of 12-14 years (p<0.05). Conclusion: Patients with BPC have smaller maxillary dental arch widths and larger mandibular intermolar widths than those without BPC. The difference in the molar buccolingual angulation between them increases with advancing age.

Effects of a flash-free system on dental plaque accumulation and bonding-debonding process: A clinical study.

INTRODUCTION: The objectives of this study were to evaluate the effects of a flash-free (FF) System on (1) the amount of plaque accumulation around the braces on buccal surfaces of the teeth, (2) the time required for the placement of brackets, including the clean-up of the flash, (3) the amount of adhesive left on the tooth after debonding, and (4) time required for adhesive remnant clean-up. METHODS: Thirty-six patients (aged 19.96 ± 5.74 years) were randomly distributed to receive adhesive precoat (APC)-FF and APC-Plus ceramic brackets on the maxillary right or left anterior 6 teeth. Bonding and debonding time were measured per segment in milliseconds. A plaque revealer agent was applied to discolor the dental plaque, and a modified plaque accumulation index was used to evaluate the amount of plaque at 2 different time points. An adhesive residue index was used after the debonding. RESULTS: The mean bonding times were 138.87 seconds (8332.47 milliseconds) and 77.82 seconds (4669.31 milliseconds) for APC-Plus and APC-FF, respectively. The difference was statistically significant (P ≤0.001). The difference between the mean debonding times was not statistically significant. A significant difference was found between the adhesive residue index scores of the 2 systems (P ≤0.001). There was no statistically significant difference between plaque accumulation scores at first- and second-time points for both adhesive systems. APC-Plus score (0.94 ± 0.98) was higher than the APC-FF score (0.50 ± 0.91) on the incisal side at the second time point (P ≤0.05). CONCLUSIONS: FF adhesives can be a good alternative to reduce chair time in bonding appointments.

Evaluation of Initial Stress Distribution and Displacement Pattern of Craniofacial Structures with 3 Different Rapid Maxillary Expansion Appliance Models: A 3-dimensional Finite Element Analysis.

OBJECTIVE: This study aimed to describe the displacement of anatomical structures and the stress distributions caused by the Hyrax, fan-type, and double-hinged expansion screws via the 3-dimensional (3D) finite element method (FEM). METHODS: The 3D FEM was based on the computed tomography data of a 12-year-old patient with a constricted maxilla. The Hyrax model included 1,800,981 tetrahedral elements with 2,758,217 nodes. The fan-type model included 1,787,558 tetrahedral elements with 2,737,358 nodes. The double-hinged model included 1,777,080 tetrahedral elements with 2,722,771 nodes. The von Mises stress distributions after 0.2 mm of expansion and displacement patterns after 5 mm of expansion were evaluated. RESULTS: The highest stress accumulation was observed in the sutura zygomatico maxillaris area with all 3 appliances. An increase in stress was noted at the pterygomaxillary fissure, the medial and lateral pterygoid process of the sphenoid bone, and the nasal areas. The wedge-shaped skeletal opening was observed with all 3 appliances. In the transverse plane, maximum posterior expansion was achieved with the Hyrax appliance, whereas the maximum anterior expansion was observed with the double-hinged appliance. The maxilla moved inferiorly and anteriorly with all the 3 appliances. The greatest inferior displacement of the maxilla was recorded with the Hyrax appliance, whereas anterior maxillary displacement was the greatest with the double-hinged appliance. CONCLUSION: All the appliances showed similar stress distributions. The use of double-hinged screw caused a slight anterior displacement of point A. The fan-type and double-hinged appliances were shown to be more effective on anterior maxillary constriction, whereas the Hyrax appliance might be chosen for resolving maxillary posterior constriction.

Stress Distribution and Displacement of Craniofacial Structures Following Rapid Maxillary Expansion in Different Types of Cleft Palate: A Three-Dimensional FEM Study.

OBJECTIVE: To evaluate displacements and stress distributions in finite element models (FEMs) of the craniofacial complex of 13-yearold male patient with complete unilateral cleft palate (UCP), a 15-year-old female patient with complete bilateral cleft palate (BCP), and a 15-year-old female patient with isolated cleft palate (ICP), which may respond differently to expansive forces. METHODS: The FEMs were based on computed tomography scans of patients with UCP, BCP, and ICP who needed maxillary expansion. Von Mises stress distribution after 0.2 mm of expansion and displacements after 5 mm of expansion were investigated. RESULTS: The highest amount of stress was observed in the ICP model. Surprisingly, no stress was noted around the nose in the BCP model. The amount of dentoalveolar expansion decreased from anterior to posterior on the cleft side of the UCP, BCP, and ICP models. In contrast, on the non-cleft side of the UCP model, the maximum dentoalveolar expansion occurred at the molar area, decreasing toward the anterior parts. Anatomical structures expressed posterior displacement in the UCP model. In the ICP model, structures close to midline showed anterior displacement, while structures in the lateral parts showed posterior displacement. In contrast with the other 2 models, the structures in the BCP model showed anterior displacement. Vertically, all the anatomic structures in the BCP model showed inferior displacement, while in the ICP and UCP models, only the structures close to the midline showed inferior displacement. CONCLUSION: Maxillary expansion caused different patterns of stress distribution and displacement in different types of clefts. Clinicians should consider the type of the cleft, and may expect differing patterns of widening following maxillary expansion.

Does audiovisual information affect anxiety and perceived pain levels in miniscrew application? - a within-person randomized controlled trial.

BACKGROUND: Anxiety can cause difficulties during surgical procedures. The main objective of this study was to evaluate changes in patients' anxiety and perceived pain levels after receiving audiovisual and verbal information about miniscrew application. MATERIALS AND METHODS: Eighty-eight patients (30 males and 58 females) with a mean age of 18.18 ± 5.39 years who had fixed orthodontic treatment and required miniscrew anchorage took part in this questionnaire-based randomized controlled trial. The participants were randomly allocated to two groups and either watched a video depicting miniscrew application (study group, 44 patients) or were informed verbally about the procedure (control group, 44 patients) before miniscrew placement. The audiovisual information was given via a video containing footage of local anesthesia injection, topical antiseptic application, and miniscrew insertion. The Spielberger State-Trait Anxiety Inventory (STAI) was used to measure anxiety immediately before miniscrew application. Self-drilling miniscrews (8 mm length, 1.5 mm diameter; Aarhus System Miniscrews, American Orthodontics, Washington, USA) were placed in posterior buccal interdental region. Each patient received only one miniscrew. Postoperative pain (PP) was determined using a 100-mm horizontal visual analog scale (VAS). RESULTS: State and total anxiety scores were significantly higher in the study group than in the control group (p = 0.009 and p = 0.011 respectively). The mean PP scores (SD) for control and study groups were 12.86 (14.22) and 12.8 (16.22), respectively. The results of Mann-Whitney U test showed no significant difference (p > 0.05). Participants' PP scores did not have a significant effect on state, trait, or total anxiety scores. There was a weak but significant positive correlation between trait anxiety and state anxiety scores in both groups. CONCLUSION: Using an audiovisual method to inform patients about miniscrew placement increased anxiety levels but did not affect pain perception.

Effects of different settings for 940 nm diode laser on expanded suture in rats.

OBJECTIVES: To evaluate the effects of the Indium Gallium Arsenide Phosphoride (InGaAsP) diode laser at different energy levels on orthopedically expanded midpalatal sutures of rats. MATERIALS AND METHODS: Eighty Wistar rats were randomly divided into four groups: a control group and low-, moderate-, and high-level laser groups with amounts of energy irradiated at 0 J, 18 J, 42 J, and 60 J, respectively. Each group was divided into two subgroups (n = 10) according to the schedule of sacrifice (7 and 21 days). Laser application (940 ± 10 nm, 0.1 W) was completed twice weekly until sacrifice. The number of osteoblasts (OB), osteocytes (OC), and vessels (V); area of connective tissue (CT); inflammation (IN); and newly formed bone (NB); as well as the ratio of newly formed bone to the total bone area (N/T) were evaluated statistically at a significance level of P < .05. RESULTS: For the low-level laser group, OB, NB, and N/T were significantly higher, and CT was lower, on both the 7th and 21st days. The amount of OC was significantly higher in the low-level laser group compared with the control group on the 7th day and the control and high-level laser groups on the 21st day. The IN was significantly higher for the high-level group on the 21st day compared with other groups. Both the moderate-level and high-level laser groups possessed fewer vessels than the low-level laser group on the 21st day. CONCLUSIONS: The InGaAsP laser at the low dosage induced a favorable effect on bone formation in the orthopedically expanded midpalatal suture of rats.

Do total or partial etching procedures effect the rate of white spot lesion formation? A single-center, randomized, controlled clinical trial.

OBJECTIVE: To determine whether total or partial etching procedures influence the appearance of white spot lesions (WSLs). MATERIALS AND METHODS: This split-mouth, double-blind, controlled, randomized study included 20 patients (mean age 16.75 years), who had class I malocclusion, mild crowding, and satisfactory oral hygiene. A total of 40 maxillary quadrants were randomly allocated to be treated using a total etching (TE) or partial etching (PE) protocol. Quantitative light fluorescence images were captured at the beginning and at 3 (T1) and 6 (T2) months after beginning orthodontic treatmen, as well as when the debonding phase of orthodontic treatment was complete (T3). The presence of pre- and posttreatment WSLs was assessed with quantitative light fluorescence software and analyzed with Student's t-test. RESULTS: The analyses showed that, at T2, the total etching group had significantly higher ΔQ and A scores than the partial etching group ( P < .05). The ΔF scores increased significantly at all timepoints in the TE group, but only at T1 and T3 in the PE group. However, no differences were noted at T3 between the TE and PE groups ( P > .05). The inclusion of only right-handed people may have limited the generalizability of the findings. The absence of analyses of the plaque and gingivitis scores of patients was another limitation of this study. CONCLUSIONS: WSL formation was observed mostly in maxillary lateral incisor teeth irrespective of the etching technique. Although PE seems to be more successful in the first 6 months, no difference was observed between PE and TE in the long term for WSL formation.

Intrapulpal Temperature Increase During Er:YAG Laser-Aided Debonding of Ceramic Brackets.

OBJECTIVE: The purpose of this study was to evaluate the temperature changes in the pulp chamber while using a newly introduced application of Er:YAG laser to debond ceramic brackets in a study model with a pulpal circulation with and without thermocycled samples. BACKGROUND DATA: An esthetic alternative to stainless steel brackets, ceramic brackets have been proposed. However, because of their low fracture resistance and high bond strengths, ceramic brackets can cause a problem when they are being removed using conventional techniques. MATERIALS AND METHODS: Experimental Groups A and B were established for samples with or without thermocycling. The same 20 maxillary central incisor and 20 premolar teeth were used in both groups. Pulpal blood microcirculation was simulated using an apparatus described in a previous study. Monocrystalline brackets were bonded by using Transbond XT. In Group A, brackets were debonded using the Er:YAG laser (600 mJ, 2 Hz, long pulse, and no air or water spray) after being stored in distilled water for 24 h. In Group B, brackets were debonded using the same laser system as that used in Group A after being stored in distilled water for 24 h and then thermocycled for a total of 5000 cycles between 5°C and 55°C. The laser irradiation duration and intrapulpal temperature changes were measured. RESULTS: In Group B, the intrapulpal temperature increase of the central incisors was significantly higher than that of the premolar teeth. In the central incisor and premolar teeth groups, there were no statistically significant difference between Groups A and B (p > 0.05). A positive correlation was found between laser irradiation duration and temperature increase (p < 0.01). CONCLUSIONS: The use of Er:YAG laser is an effective method for debonding the monocrystalline ceramic brackets. This method can be used safely under the consideration of intrapulpal temperature changes.

The effect of different concentrations of topical ozone administration on bone formation in orthopedically expanded suture in rats.

BACKGROUND/OBJECTIVE: The aim of this study was to investigate the effects of different concentrations of ozone (O3) therapy on bone regeneration in response to an expansion of the inter-premaxillary suture in rats. MATERIALS AND METHODS: Forty-eight Wistar rats were randomly divided into four groups (n = 12). In groups I, II, and III, 1ml of O3 at 10, 25, and 40 µg/ml was injected at the premaxillary suture, respectively. In group IV (control group), 1ml of saline solution was injected at the same point during the expansion procedure for 5 days. Bone regeneration in the suture was evaluated histomorphometrically. The area of new bone and fibrotic area, the number of osteoblasts and osteoclasts, and the amount of vascularity were measured and compared. The density of the newly formed bone in the expansion area was measured by using cone beam computed tomography. Data were analyzed using the Kruskal-Wallis one-way analysis of variance and post hoc Student-Newman-Keuls tests. RESULTS: New bone area, fibrotic area, osteoblast and osteoclast numbers, and the amount of vascularity were significantly higher in experimental groups compared with the control group (P < 0.001). The density of newly formed bone (P < 0.001), new bone formation (P = 0.009), number of capillaries (P < 0.001), number of osteoclasts (P = 0.016), and number of osteoblasts (P < 0.001) in the maxillary sutures were highest in the 25 µg/ml O3 group compared with the other experimental groups and control group. CONCLUSIONS/IMPLICATIONS: The application of O3 therapy can stimulate bone regeneration in an orthopedically expanded inter-premaxillary suture during both the expansion and retention periods.

Reliability Assessment of Orthodontic Apps for Cephalometrics.

OBJECTIVE: The aim of this study was to evaluate the accuracy and reliability of cephalometric measurements using iPad apps called CephNinja and SmartCeph Pro. The measurements were compared with the measurements obtained using Dolphin Imaging computer software. METHODS: Twenty digital cephalometric radiographs were randomly selected from the archives and traced using the CephNinja app, SmartCeph Pro app, and Dolphin Imaging software. Twenty-one landmarks and 16 measurements were performed in each program. The statistical analysis was conducted using the Bland-Altman analysis at a significance level of 0.05. RESULTS: For the CephNinja app, there were seven measurements that were in accordance with Dolphin Imaging software. For the SmartCeph Pro app, six measurements were in accordance with Dolphin software. Both apps gave better results for angular measurements than linear ones. CONCLUSION: These findings indicate that, although they are user-friendly, orthodontic apps for cephalometrics are not equal with Dolphin software now and need to be developed to be more reliable for most of the measurements.

Temperature rise caused in the pulp chamber under simulated intrapulpal microcirculation with different light-curing modes.

OBJECTIVE: To evaluate and compare intrapulpal temperature rise with three different light-curing units by using a study model simulating pulpal blood microcirculation. MATERIALS AND METHODS: The roots of 10 extracted intact maxillary central incisors were separated approximately 2 mm below the cement-enamel junction. The crowns of these teeth were fixed on an apparatus for the simulation of blood microcirculation in pulp. A J-type thermocouple wire was inserted into the pulp chamber through a drilled access on the palatal surfaces of the teeth. Four measurements were made using each tooth for four different modes: group 1, 1000 mW/cm(2) for 15 seconds; group 2, 1200 mW/cm(2) for 10 seconds; group 3, 1400 mW/cm(2) for 8 seconds; and group 4, 3200 mW/cm(2) for 3 seconds. The tip of the light source was positioned at 2 mm to the incisor's labial surface. RESULTS: The highest temperature rise was recorded in group 1 (2.6°C ± 0.54°C), followed by group 2 (2.57°C ± 0.62°C) and group 3 (2.35°C ± 0.61°C). The lowest temperature rise value was found in group 4 (1.74°C ± 0.52°C); this value represented significantly lower ΔT values when compared to group 1 and group 2 (P  =  .01 and P  =  .013, respectively). CONCLUSIONS: The lowest intrapulpal temperature rise was induced by 3200 mW/cm(2) for 3 seconds of irradiation. Despite the significant differences among the groups, the temperature increases recorded for all groups were below the critical value of 5.6°C.

Comparison of three different orthodontic wires for bonded lingual retainer fabrication.

OBJECTIVE: We evaluated the detachment force, amount of deformation, fracture mode, and pull-out force of 3 different wires used for bonded lingual retainer fabrication. METHODS: We tested 0.0215-inch five-stranded wire (PentaOne, Masel; group I), 0.016 × 0.022-inch dead-soft eight-braided wire (Bond-A-Braid, Reliance; group II), and 0.0195-inch dead-soft coaxial wire (Respond, Ormco; group III). To test detachment force, deformation, and fracture mode, we embedded 94 lower incisor teeth in acrylic blocks in pairs. Retainer wires were bonded to the teeth and vertically directed force was applied to the wire. To test pull-out force, wires were embedded in composite that was placed in a hole at the center of an acrylic block. Tensile force was applied along the long axis of the wire. RESULTS: Detachment force and mode of fracture were not different between groups. Deformation was significantly higher in groups II and III than in group I (p < 0.001). Mean pull-out force was significantly higher for group I compared to groups II and III (p < 0.001). CONCLUSIONS: Detachment force and fracture mode were similar for all wires, but greater deformations were seen in dead-soft wires. Wire pull-out force was significantly higher for five-stranded coaxial wire than for the other wires tested. Five-stranded coaxial wires are suggested for use in bonded lingual retainers.

Comparison of the outcomes of the lower incisor extraction, premolar extraction and non-extraction treatments.

The aim of this retrospective study was to evaluate the treatment outcome of lower incisor extraction and to compare it with premolar extraction and non-extraction treatment. The sample consisted of 60 subjects with Class I malocclusion and moderate crowding. The sample was separated into three groups: extraction of a lower incisor group, extraction of a four first premolar group and a non-extraction group. All groups involved 13 girls and 7 boys with a total of 20 patients. The Peer assessment rating (PAR) index was applied to a patient's pre-treatment (T1) and post-treatment (T2) dental casts. T1 dental casts were also used for determining Bolton discrepancy. One-way analysis of variance and post hoc Tukey HSD tests were used for statistical analysis. For the mean percentage PAR score reduction for each group, there was one significant difference seen between the lower incisor extraction group and the non-extraction group (P = 0.047). For the mean anterior ratios, there were significant differences among premolar extraction group versus non-extraction group (P = 0.042) and non-extraction group versus lower incisor extraction group (P = 0.000). For the mean overall ratios, there were significant differences among the premolar extraction group versus lower incisor extraction group (P = 0.048) and the non-extraction group versus lower incisor extraction group (P = 0.001). Orthodontic treatment without extraction has a better treatment outcome than the four-first premolar extraction and single lower incisor extraction protocols in Class I cases with moderate to severe mandibular anterior crowding.

Effects of high-intensity curing lights on microleakage under orthodontic bands.

INTRODUCTION: Our objective was to compare the effects of 3 light-curing units (LCUs) (quartz-tungsten-halogen [QTH], light-emitting diode [LED], and plasma-arc curing [PAC]) on the microleakage patterns of a polyacid-modified composite (PAMC) for band cementation between the cement-enamel and the cement-band interfaces from the buccal, lingual, occlusal, and gingival margins. METHODS: Sixty freshly extracted third molars were randomly divided into 3 groups of 20 teeth each. Microetched molar bands were cemented in all groups with the PAMC (Ultra Band-Lok, Reliance Orthodontic Products, Itasca, Ill) and cured for 30 seconds with the QTH (Hilux 350, Express Dental Products, Toronto, Ontario, Canada), for 20 seconds with the LED (Elipar Freelight 2, 3M Espe, Seefeld, Germany), or for 6 seconds with the PAC (Power-Pac, American Medical Technologies, Hannover, Germany). A dye penetration method was used for microleakage evaluation. Microleakage was determined with a stereomicroscope for the cement-band and cement-enamel interfaces from the buccal and lingual sides at the occlusal and gingival margins. Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was set at P <0.05. RESULTS: The gingival sides in the LED and PAC groups had higher microleakage scores compared with those observed on the occlusal sides at both the cement-band and cement-enamel interfaces. The buccal sides had similar microleakage values compared with those on the lingual sides for the cement-enamel and cement-band interfaces in all LCU types. Statistical comparisons showed that there were statistically significant differences among the investigated LCUs at the cement-enamel interface (P <0.05). Post hoc comparisons showed statistically significant microleakage differences between the PAC (median, 0.950 mm), the QTH (median, 0.383 mm) (P <0.01), and the PAC and the LED (median, 0.558 mm) (P <0.05) LCUs at the cement-enamel interfaces. CONCLUSIONS: The high-intensity curing device PAC is associated with more microleakage than the LED and QTH at the cement-enamel interface.

Amorphous calcium phosphate-containing orthodontic cement for band fixation: an in vitro study.

AIM: To evaluate the shear bond strength (SBS) and fracture mode of amorphous calcium phosphate (ACP)-containing and conventional glass-ionomer cement (GIC) for band fixation. METHODS: Sixty extracted human third molars were embedded in acrylic resin blocks, leaving the buccal surface of the crowns parallel to the base of the molds. The teeth were randomly divided into two groups containing 30 teeth each. GIC (group 1, Ketac-Cem) or ACP-containing orthodontic cement (group 2, Aegis-Ortho) was applied onto microetched strip band material (4.0 × 3.8 mm), which was then attached to the tooth surfaces. With a universal testing machine, each cemented band strip was shear mode loaded until failure. Thereafter, all teeth and band strips were examined under 10× magnification. The remaining cement was assessed with a modified Adhesive Remnant Index (ARI). The SBS data were analyzed using the t test and the fracture modes by the chi-square test. RESULTS: There was no significant difference between the bond strength of group 1 (GIC, mean: 28.9 ± 15.2 MPa) and group 2 (ACP-containing cement, mean: 26.3 ± 11.8 MPa). The fracture modes differed significantly between the two groups (P<.01). CONCLUSION: Both groups had a similar level of SBS. The fracture sites of the ACP-containing cement were predominantly in the enamel-cement interface.

Microleakage of orthodontic band cement at the cement-enamel and cement-band interfaces.

INTRODUCTION: Our objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC), resin modified GIC (RMGIC), and polyacid-modified composite for band cementation. METHODS: Sixty freshly extracted third molars were randomly divided into 3 groups of 20 teeth each. Microetched molar bands in the 3 groups were cemented to enamel with one of three orthodontic cements: Ketac-Cem (3M ESPE, Gmbh, Seefeld, Germany), Multi-Cure (3M Unitek, Monrovia, Calif), and Transbond Plus (3M Unitek). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces from both the buccal and lingual margins. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The buccal sides had similar microleakage values compared with the lingual sides for the cement-enamel and cement-band interfaces with all cements. Statistical comparisons showed statistically significant differences among the band cements between both interfaces (P <0.001). When the cement systems were compared, conventional GIC showed the highest leakage scores between cement-band (median, 3.50 mm) and cement-enamel (median, 2.88 mm) interfaces. Teeth banded with RMGIC and modified composite showed similar microleakage scores, and both had less leakage (<1 mm) than conventional GIC. CONCLUSIONS: Conventional GIC is associated with more microleakage than RMGIC and modified composite at both the cement-band and cement-enamel interfaces.

Investigation of bacteremia following insertion of orthodontic mini-implants.

AIM: To investigate the incidence of bacteremia in the bloodstream immediately after orthodontic mini-implant insertion, which can be an invasive procedure. METHODS: Blood samples (10 mL) were taken before and after mini-implant insertion from 40 patients (18 males, 22 females; mean age 21.3 ± 7.7 years). These samples were inoculated into BacT/Alert aerobic and anaerobic blood culture bottles and processed in a BacT/Alert 9240 Blood Culture System. The findings were analyzed with the McNemar test. RESULTS: No bacteremia was detected in the pretreatment samples, but it was in one of the postprocedure samples. The respective bacteria was Streptococcus sanguinis, which is strongly associated with bacterial endocarditis. CONCLUSION: Orthodontic mini-implant placement might possibly be correlated to transitory bacteremia. Therefore, a very careful approach seems indicated when dealing with patients who are at risk for cardiopathic complications.

Microleakage under orthodontic brackets bonded with the custom base indirect bonding technique.

The aim of this in vitro study was to compare microleakage of orthodontic brackets between enamel-composite and composite-bracket interfaces at the occlusal and gingival margins, bonded using indirect bonding systems with that of a conventional direct bonding method. Forty freshly extracted human maxillary premolar teeth were randomly divided into two groups. In group 1, the brackets were bonded to teeth directly according to the manufacturer's recommendations. Group 2 consisted of 20 teeth bonded indirectly with Transbond XT (3M-Unitek), as the adhesive, and Sondhi Rapid Set A/B Primer (3M-Unitek), a filled resin primer. After bonding, the specimens were further sealed with nail varnish, stained with 0.5 per cent basic fuchsine for 24 hours, sectioned and examined under a stereomicroscope, and scored for microleakage at the enamel-composite and composite-bracket interfaces from both the occlusal and gingival margins. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction. The gingival sides of group 1 displayed a higher median microleakage score than the occlusal side at the enamel-composite interface but this was not statistically significant (P > 0.05). All occlusal margins in both groups showed no microleakage under orthodontic brackets at the enamel-composite or composite-bracket interfaces. Comparisons of the microleakage scores between the direct and the indirect bonding groups at the enamel-composite and composite-bracket interfaces indicated no statistically significant microleakage differences at the gingival and occlusal margins (P > 0.05). The type of bonding method (direct versus indirect) did not significantly affect the amount of microleakage at the enamel-composite-bracket complex.

Maxillary expansion in the mixed dentition: rapid or semi-rapid?

The purpose of this study was to investigate the effects of rapid maxillary expansion (RME) and semi-rapid maxillary expansion (SRME) in the mixed dentition period. The SRME group consisted of 18 patients (11 girls and 7 boys) with a mean age of 8.63 +/- 1.09 years and the RME group 17 patients (11 girls and 6 boys) with a mean age of 8.78 +/- 1.21 years. A splint type tooth- and tissue-borne modified bonded RME appliance was used, with the patients activating the screw two-quarter turns per day for the first week, followed by one-quarter turn every other day in the SRME group and two-quarter turns per day throughout treatment in the RME group. The average treatment time was 57.16 +/- 21.52 and 21.23 +/- 8.36 days for the SRME and RME groups, respectively. A Wilcoxon signed rank test was used to evaluate the treatment effects [pre-(T(0)) - post-(T(1)) treatment changes] for both the SRME and RME groups and a Mann-Whitney U-test to determine the differences between the two groups (T(0)-T(1) changes SRME versus T(0)-T(1) changes RME). For both groups, the maxillary base, nasal cavity width and upper intercanine and intermolar distances were increased, and the upper molars tipped buccally. The only statistically significant (P < 0.05) difference between two groups was in inferior movement of posterior nasal spine (PNS) relative to the SN plane (SN upper left and right quadrantsPNS). This measurement increased in both groups yet significantly more in the RME group. The results suggest that RME and SRME have similar effects on dentofacial structures both in the transverse, vertical, and sagittal planes.

Condylar and ramal vertical asymmetry in unilateral and bilateral posterior crossbite patients and a normal occlusion sample.

INTRODUCTION: Our objective was to evaluate the condylar, ramal, and condylar-plus-ramal mandibular vertical asymmetry in a group of adolescent subjects with normal occlusion and unilateral and bilateral posterior crossbite malocclusions. METHODS: Mandibular asymmetry index measurements (condylar, ramal, and condylar-plus-ramal) were made on the panoramic radiographs of 126 subjects (51 boys, 75 girls). The study groups consisted of 46 unilateral (19 boys, 27 girls; mean age, 13.06 +/- 3.52 years) and 40 bilateral (16 boys, 24 girls; mean age, 12.72 +/- 3.22 years) posterior crossbite patients and a group of 40 subjects (16 boys, 24 girls; mean age, 14.43 +/- 3.05 years) with normal occlusion. One-way analysis of variance (ANOVA) was used to determine possible statistically significant differences between the groups for condylar, ramal, and condylar-plus-ramal asymmetry index measurements at the 95% confidence interval. RESULTS: No group showed statistically significant sex- or side-specific differences for posterior vertical height measurements (P > 0.05). Asymmetry indexes (condylar, ramal, and condylar-plus-ramal) were similar, and no statistically significant differences were found among the unilateral and bilateral posterior crossbite groups and the normal occlusion sample. CONCLUSIONS: No statistically significant sex- or side-specific mandibular asymmetry was found among the 3 groups. Condylar asymmetry index values were significantly high compared with the 3% threshold value in each of the 3 groups, but comparisons between groups were not statistically significant.