World journal of orthodontics最新文献

Aim: To evaluate the periodontal status and orthodontic treatment need of autistic children and compare these findings to nonaffected, same-age individuals.

Method: The periodontal status and orthodontic treatment need were evaluated in 32 autistic and 48 nonautistic boys and girls age 8 years to 12 years (mean 9.7 ± 1.2 years and 9.9 ± 1.1 years, respectively). The periodontal status of all subjects was recorded using the Community Periodontal Index of Treatment Need (CPITN) with a slight modification. The orthodontic treatment need was determined using the Dental Aesthetic Index (DAI). Chi-square test and odds ratio were used for statistical analysis.

Results: No significant sex differences were found in the autistic or nonautistic groups. The autistic children presented with a significantly poorer periodontal status than the nonautistic children (P<.05). No significant differences in terms of the various malocclusion categories were found between both groups (P>.05); however, children with autism showed missing teeth, spacing, diastemas, reverse overjets, open bites, and Class II molar relationship tendencies in a higher percentage than nonautistic individuals. In all, autistic children and nonautistic children frequently needed orthodontic treatment.

Conclusion: This study suggests that children with autism require special dental management to improve their oral hygiene as well as their dental esthetics. More care from parents, general dentists, and pedodontists/orthodontists should be provided routinely to autistic children.

Aim: To determine the tangential tensile force loading behavior of mini-implants relative to cortical bone thickness in the porcine mandible.

Methods: Eighteen mini-implants were placed both anteriorly and posteriorly perpendicular to the bone surface in porcine mandibles and subjected to shear tests using a Universal Testing Machine (Instron). Further, cone beam CT was used to measure cortical bone thickness at each mini-implant site.

Results: The shear strength differed significantly between the anterior (mean 89.05 ± 35.9 N) and posterior (mean 179.85 ± 29.01 N) sites. The same was true for the cortical bone thickness (anteriorly, mean 3.59 ± 0.49 mm; posteriorly, mean 4.24 ± 0.5 mm).

Conclusion: The shear forces required to dislodge mini-implants were much higher than forces typically applied for orthodontic purposes. Therefore, mandibular cortical bone supporting monocortical orthodontic mini-implants would most likely withstand immediate loading with tangential shear forces. In addition, it seems that mini-implants loaded tangentially continue to exhibit adequate anchorage for orthodontic forces even after they are displaced.

This is a report about the orthodontic treatment of a 13-year, 10-month-old boy with total ankyloglossia combined with a Class III occlusion. The patient's tongue was fixed to the floor of his mouth and could not be elevated at all. He had a maxillary deficiency and a mandibular protrusion with a negative overjet. However, he was able to retrude his mandible to an edge-to-edge position. Before orthodontic treatment, the ankyloglossia was surgically rectified. Orthodontic treatment was initiated to improve the patient's occlusion and facial appearance by correcting his retruded maxilla by means of a face mask, fixed appliances, and Class III elastics. This led to a functional occlusion and an acceptable facial appearance.

Aim: To compare friction (F) of conventional and ceramic brackets (0.022-inch slot) using a model that tests the sliding of the archwire through 10 aligned brackets.

Methods: Polycrystalline alumina brackets (PCAs), PCA brackets with a stainless steel slot (PCA-M), and monocrystalline sapphire brackets (MCS) were tested under elastic ligatures using various archwires in dry and wet (saliva) states. Conventional stainless steel brackets were used as controls.

Results: In both dry and wet states, PCA and MCS brackets expressed a statistically significant higher F value with respect to stainless steel and PCA-M brackets when combined with the rectangular archwires (P<.01). PCA brackets showed significantly higher friction than MCS brackets (P<.01) when coupled with 0.014 x 0.025-inch nickel-titanium (Ni-Ti) archwire. SEM analysis showed differences in the surfaces among stainless steel, MCS, PCA-M, and PCA brackets. In the wet state, the mean F values were generally higher than in the dry state.

Conclusion: PCA brackets showed significantly higher F than MCS brackets only when combined with 0.014 x 0.025-inch Ni-Ti archwires. Thus, in this study, a 10 aligned-brackets study model showed similar results when compared to a single bracket system except for friction level with 0.014 × 0.025-inch Ni-Ti archwires.

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.

Aim: To evaluate the effects of rapid maxillary expansion (RME) and face mask combination therapy on the soft and hard tissue profile and to determine the possible correlations between hard and soft tissue changes.

Methods: Soft and hard tissue parameters were measured in cephalometric radiographs of 33 subjects. The treatment group consisted of 18 Class III patients (11 males and 7 females, mean age 11.7 ± 1.9 years), and the control group contained 15 untreated Class III subjects (10 males and 5 females, mean age 9.1 ± 2.5 years). Soft tissue Arnett analysis was used to evaluate the profile changes in both groups after treatment or observation. Paired- and independent-sample t tests were used for statistical evaluation.

Results: Combined RME and face mask therapy produced significant and favorable skeletal changes in both arches. The Class III incisal relationship was corrected by protrusion of the maxillary incisors and retrusion of the mandibular incisors. The soft tissue profile showed significant increase in convexity and facial height.

Conclusion: Significant forward and downward displacement of the maxilla and an opening rotation of the mandible were observed as a result of RME and face mask therapy. The soft tissue profile also improved significantly.

This report presents a case of a patient who developed a supernumerary mandibular premolar during the course of orthodontic treatment. Evidence of this tooth comes from consecutive panoramic radiographs. It is not routine practice to screen for developing supernumerary teeth during orthodontic treatment. Therefore, the possibility of supernumerary tooth interference with occlusal development or orthodontic treatment should always be kept in mind. A brief review of literature concerning the late formation of supernumerary teeth is included.

Aim: To study the effects of a prophylactic fluoride regimen on the mechanical properties of nickel-titanium (Ni-Ti) archwires under clinical conditions.

Method: The unloading properties of 100 Ni-Ti wires were tested using a three-point bending test at five deflections (0.5 mm, 1.0 mm, 2.0 mm. 3.0 mm, and 3.1 mm). Sixty-six 0.016 3 0.022-inch Ni-Ti wires were tested after being used intraorally for 6 weeks using two protocols. Thirty-three wires were evaluated after the use of fluoride-containing Crest toothpaste (sodium fluoride 0.243%, 0.15% w/v fluoride ion) and Equate fluoride rinse (sodium fluoride 0.05%, fluoride ion 0.0226%). Another 33 wires were examined after a nonfluoridated natural toothpaste (Tom's of Maine; calcium carbonate, xylitol, myrrh, propolis, sodium lauryl sulfate, carrageenan, spearmint and peppermint oils, glycerin, and water) was used. Another 34 Ni-Ti wires served as a control; they were tested as received. Statistical analyses were carried out with a linear-mixed model (analysis of variance [ANOVA]).

Results: Force degradation occurred within both groups of intraorally used wires but not in the unused archwires. When compared to unexposed wires, those with fluoride exposure exhibited slightly higher force degradation at 3.1 and 3.0 mm deflection, but they displayed less force degradation at 0.5 and 1.0 mm deflection.

Conclusions: Topical fluoride regimens decreased the unloading property of Ni-Ti wires at higher deflections but increased it at lower deflections.

The purpose of this study was to evaluate the effects of spring-loaded and magnetic bite blocks in growing individuals with skeletal open bites. The sample consisted of patients between 8 and 13 years of age randomly divided into two groups. One group was treated with spring-loaded bite blocks while the other received treatment with magnetic bite blocks. Further, a group matched for age, sex, and mandibular plane angle served as a control. The treatment effects were evaluated clinically and cephalometrically and by electromyographic (EMG) examination of the masseter and temporalis muscles after 8 months. Both appliances showed significantly (P<.05) favorable orthopedic effects. The spring-loaded bite blocks closed the existing open bite by 3.3 mm on average with a significant maxillary incisor extrusion and molar intrusion. Magnetic bite blocks produced an average of 4.9 mm of open bite closure with significant intrusion of the molars in both arches. Overall, both appliances significantly enhanced condylar growth, altered it to a more anterosuperior direction, and produced significant true forward mandibular rotation. Significant increases in masseter and temporalis muscle activity at rest and maximum clenching were noted in both groups, which could be a positive factor in retaining the achieved result. After 10 months of retention with passive bite blocks, cephalograms indicated only an insignificant relapse.

Distal movement of maxillary molars is a common approach for nonextraction treatment of Angle Class II patients. Because of known difficulties involving moving the maxillary first molars distally in the presence of second molars, this article describes how the distally directed force is applied immediately to the second molars. A rapid palatal expander can be used as a reliable unit to facilitate the distal movement of the second maxillary molars.