Ectopia and Partial Transposition of Mandibular Lateral Incisors in a Child Patient

Dental ectopia is a rare clinical finding characterized by a change in the normal tooth eruption pathway. In more severe cases, nontreated ectopia may develop into either partial or total transposition. The early diagnosis is of crucial importance for establishing a treatment planning correctly. Therefore, the present paper is aimed at reporting an unusual case of a 11-year-old boy with ectopic eruption and partial transposition of mandibular permanent lateral incisors as well as the diagnosis and therapeutic outcomes involving such an anomaly

Cone-Beam Computed Tomography and Radiographs in Dentistry: Aspects Related to Radiation Dose

Introduction. The aim of this study was to discuss the radiation doses associated with plain radiographs, cone-beam computed tomography (CBCT), and conventional computed tomography (CT) in dentistry, with a special focus on orthodontics. Methods. A systematic search for articles was realized by MEDLINE from 1997–March 2011. Results. Twenty-seven articles met the established criteria. The data of these papers were grouped in a table and discussed. Conclusions. Increases in kV, mA, exposure time, and field of view (FOV) increase the radiation dose. The dose for CT is greater than other modalities. When the full-mouth series (FMX) is performed with round collimation, the orthodontic radiographs transmit higher dose than most of the large FOV CBCT, but it can be reduced if used rectangular collimation, showing lower effective dose than large FOV CBCT. Despite the image quality, the CBCT does not replace the FMX. In addition to the radiation dose, image quality and diagnostic needs should be strongly taken into account

Shear bond strength of orthodontic brackets to enamel under different surface treatment conditions

The purpose of the present study was to evaluate the shear bond strength to enamel and the adhesive remnant index (ARI) of both metallic and polycarbonate brackets bonded under different conditions. Ninety bovine permanent mandibular incisors were embedded in acrylic resin using PVC rings as molds and assigned to 6 groups (n=15). In Groups 1 (control) and 3, metallic and polycarbonate orthodontic brackets were, respectively, bonded to the enamel surfaces using Transbond XT composite according to the manufacturer's recommendations. In Groups 2 and 4, both types of brackets were bonded to enamel with Transbond XT composite, but XT primer was replaced by the OrthoPrimer agent. In Groups 5 and 6, the polycarbonate bracket bases were sandblasted with 50-mm aluminum-oxide particle stream and bonded to the enamel surfaces prepared under the same conditions described in Groups 3 and 4, respectively. After bonding, the specimens were stored in distilled water at 37ºC for 24 hours and then submitted to shear bond strength test at a crosshead speed of 0.5 mm/min. The results (MPa) showed no statistically significant difference between Groups 4 and 6 (p>;0.05). Likewise, no statistically significant differences (p>;0.05) were found among Groups 1, 2, and 5, although their results were significantly lower than those of Groups 4 and 6 (

New methodology for evaluating osteoclastic activity induced by orthodontic load

Orthodontic tooth movement (OTM) is a dynamic process of bone modeling involving osteoclast-driven resorption on the compression side. Consequently, to estimate the influence of various situations on tooth movement, experimental studies need to analyze this cell. Objectives The aim of this study was to test and validate a new method for evaluating osteoclastic activity stimulated by mechanical loading based on the fractal analysis of the periodontal ligament (PDL)-bone interface. Material and Methods The mandibular right first molars of 14 rabbits were tipped mesially by a coil spring exerting a constant force of 85 cN. To evaluate the actual influence of osteoclasts on fractal dimension of bone surface, alendronate (3 mg/Kg) was injected weekly in seven of those rabbits. After 21 days, the animals were killed and their jaws were processed for histological evaluation. Osteoclast counts and fractal analysis (by the box counting method) of the PDL-bone interface were performed in histological sections of the right and left sides of the mandible. Results An increase in the number of osteoclasts and in fractal dimension after OTM only happened when alendronate was not administered. Strong correlation was found between the number of osteoclasts and fractal dimension. Conclusions Our results suggest that osteoclastic activity leads to an increase in bone surface irregularity, which can be quantified by its fractal dimension. This makes fractal analysis by the box counting method a potential tool for the assessment of osteoclastic activity on bone surfaces in microscopic examination

Rates of tooth movement and bone remodeling activity : self-ligating versus conventional brackets

Background: Bracket systems have been developed with the purpose of reducing frictional resistance between the archwire and accessories. The aim of this research was to compare rates of tooth movement and regions of cellular bone modeling activity along tooth root surfaces of teeth moved with conventional vs. self-ligating brackets. Material and Methods: The experiments were conducted in 20 male dogs. Bands were cemented in all intermediate incisors, with conventional brackets (Morelli) on the right side and hybrid self-ligating ones (T3-American Ortho-dontics) on the left side. A 0.019? x 0.025? stainless steel wire was inserted passively in the slot of these brackets with chain elastics (250 gf) to perform sliding mechanics. Clinical records of the orthodontic mechanics were made before and after 15 days of the tooth movement. The dental segments of the animals were prepared for light micros-copy. Statistical analysis of variance and the Tukey correction with a P value at 5% were used. Results: There were no significant differences in tooth movement rates between the two types of brackets but di-fferences, in the bone modeling activity, suggested that tooth movement with the self-ligating brackets resulted in more tipping and less translational movement than tooth movement with the conventional brackets. Conclusions: The rates of tooth movement were similar between the two systems. The histological evaluation of cellular bone modeling activity along tooth root surfaces showed more translation movement of teeth with the con-ventional brackets, and more tipping movement of teeth with self-ligating brackets

INFLUENCE OF LOW-LEVEL LASER APPLICATION ON ROOT RESORPTION AND PULP ALTERATIONS DURING TOOTH MOVEMENT

http://dx.doi.org/10.5902/223658345042The purpose of this study was to determine the effects of low-level laser (LLL) irradiation on root resorption and dental pulp during experimental tooth movement. Five groups were delineated: a control group without orthodontic force or LLL application, 2 other controls in which orthodontic force was applied for 2 and 7 days respectively, and two experimental groups with orthodontic force and LLL application for 2 and 7 days respectively. To induce experimental tooth movement in rats, orthodontic force of 40 cN was applied to the left first molars. In irradiated groups, Ga-Al-As diode laser (830 nm) was applied on 3 areas around the experimental maxillary molar: mesial, buccal and palatal. Two microscopic analyses were performed with HE staining: a quantitative for root resorption and a qualitative for pulp tissue reactions. Quantitative analysis showed that root resorptions were evident on day 7 of tooth movement. The irradiated group presented twice the amount of root resorption than the orthodontic control group, but this difference was not verified statistically (P=0.073). The qualitative pulp evaluation showed no significant alterations when orthodontic force or LLL were applied. Root resorption was verified when LLL was applied and no undesired effects on pulp tissue were observed. KEY WORDS: laser therapy, low-level; tooth movement; root resorption; dental pul

Long-term maxillary behavior in treated skeletal Class II malocclusion

Aim: To evaluate the post-treatment and long-term anteroposterior and vertical maxillary changes from the use of Kloehn cervical headgear in treated skeletal Class II Division 1 malocclusion. Methods: Using a longitudinal prospective study design, 90 lateral radiographs of 30 treated patients (12 male gender and 18 female gender) were taken at the beginning of the treatment (mean age = 10 years and 9 month), at the end of the treatment (mean age = 14 years and 6 months), and in the post-retention phases (mean age = 26 years and 2 months). Lateral radiographs of 30 adults patients with Class II malocclusion, as control group (mean age = 24 years and 1 month) were compared with lateral radiographs of patients in the post-retention phase in order to quantify the cephalometric measurements (5 angular and 2 linear) representing the maxillary position in the anteroposterior and vertical direction. Results: Under the effect of treatment, forward displacement of the maxilla was redirected in a downwards and backwards direction. When the means of the female measurements were compared between the two groups, only ANB was greater in the control group. When the male measurements were compared, they presented a mean value of ANB greater in the control group, and the mean of SNPP greater in the treated group. Conclusions: In the post-retention phase, maxillary displacement reverted in a downward and forward direction, confirming the transitory effect of the extra-oral action on maxillary displacement

Long-term maxillary behavior in treated skeletal Class II malocclusion

evaluate the post-treatment and long-term anteroposterior and vertical maxillary changes from the use of Kloehn cervical headgear in treated skeletal Class II Division 1 malocclusion. Methods: Using a longitudinal prospective study design, 90 lateral radiographs of 30 treated patients (12 male gender and 18 female gender) were taken at the beginning of the treatment (mean age = 10 years and 9 month), at the end of the treatment (mean age = 14 years and 6 months), and in the post-retention phases (mean age = 26 years and 2 months). Lateral radiographs of 30 adults patients with Class II malocclusion, as control group (mean age = 24 years and 1 month) were compared with lateral radiographs of patients in the post-retention phase in order to quantify the cephalometric measurements (5 angular and 2 linear) representing the maxillary position in the anteroposterior and vertical direction. Results: Under the effect of treatment, forward displacement of the maxilla was redirected in a downwards and backwards direction. When the means of the female measurements were compared between the two groups, only ANB was greater in the control group. When the male measurements were compared, they presented a mean value of ANB greater in the control group, and the mean of SNPP greater in the treated group. Conclusions: In the post-retention phase, maxillary displacement reverted in a downward and forward direction, confirming the transitory effect of the extra-oral action on maxillary displacement