Orthodontics : the art and practice of dentofacial enhancement最新文献

Aim: The aim of this study was to evaluate the effect of different methods of ligation in tie configurations on friction in dry and wet conditions.

Methods: Four methods of ligations were used: regular round tie, figure eight, twist, and diagonal. Materials used were Alastik (3M Unitek), Power O module (ORMCO), O-ring ligatures (JES), stainless steel ligatures (TP Orthodontics), 0.019 × 0.025-inch straight-length stainless steel archwires and stainless steel MBT 0.022-inch slot brackets (3M Unitek).

Results: Figure eight ligation had the highest friction, followed by round, twist, and diagonal ligation, in the descending order. Comparisons were statistically significant with a 100-g load. Dry group samples had higher friction than the wet group. These comparisons were statistically significant with a 50-g load.

Conclusions: The study concluded that figure eight ligation had the highest friction, and diagonal ligation produced the least friction. Among the dry and wet groups, lubrication showed significant reduction in friction.

Aims: To survey retention protocols and need for practical retention guidelines among orthodontists in Norway and to compare the results with similar studies in other countries.

Methods: A questionnaire was mailed to all members of the Norwegian Association of Orthodontists. It included questions about their background and their current retention protocol, as well as their perceived need for common retention guidelines.

Results: The response rate was 77.7% (69.3% males and 30.7% females). The most common maxillary retainer was a combination of a fixed and removable retainer, followed by a clear thermoplastic retainer. In the mandible, a fixed retainer bonded to all anterior teeth was most common (66.4%). Retention in the maxilla lasted 2 to 3 years (34.7%) or 3 to 5 years (23.8%). In the mandible, 41.5% of the orthodontists left the retainer in place for >5 years. When retention lasted more than 3 years, 70% of the orthodontists left the responsibility for retainer checkups to the patients or the general practitioners. The main reason for choosing a certain retention protocol was clinical experience (57.4%). Only 3.5% of the orthodontists based their protocols on information from the literature. Half?of the orthodontists, significantly women, expressed a need for common retention guidelines.

Conclusions: In Norway, bonded retainers alone were reported to be most commonly used in the mandible, while bonded retainers used in combination with a removable retainer appear to be the most commonly used appliances in the maxilla. This is similar to the most frequently used retainers in other countries, but there are disparities in duration and follow-up protocols. Most female orthodontists desire common retention guidelines.

This clinical report presents a case treated by a currently available customized orthodontic treatment system. The use of patient-specific brackets, indirect bonding transfer devices, and customized archwires decreases treatment and chairside time, making orthodontic cases more predictable, accurate, and efficient. The need for time-consuming adjustments is greatly reduced, and appliance customization further facilitates the achievement of the final desired occlusion from the first day of treatment.

Management of severe rotation poses a great challenge for the orthodontist, especially when cortical anchorage occurs. The conventional methods require excessive treatment time, rely on patient compliance, and can cause root resorption. A groundbreaking new procedure developed by Wilcko et al, which is actually a modification of the conventional corticotomy procedure, amalgamates the orthodontic mechanics, alveolar decortications, and augmentation procedure to make treatment time three to four times faster than conventional orthodontic techniques. This procedure uses the dynamics of bone physiology and redirects the emphasis in tooth movement to the manner in which supporting bone responds to orthodontic forces applied to the tooth. This article includes a case report in which the technique is used on a patient who has a severely rotated mandibular left canine.

This report describes the use of the miniscrew as orthodontic anchorage in maxillary protrusion with a spaced arch and midline deviation in a 16-year-old female patient. In cases with midline deviation, a cant in the maxillary occlusal plane is often observed. Thus, the authors used the miniscrew to control the vertical dimension, thereby flattening the maxillary occlusal plane, and to close and retract the incisors to improve her convex profile. Effective incisor intrusion to correct the deep overbite was also observed. In addition, functional evaluation by a 6-degrees-of-freedom jaw movement recording system was performed. Significant improvement in the jaw movement was observed during maximum opening and lateral excursion during the retention phase. The authors suggest that miniscrews are effective in correcting midline deviation due to maxillary occlusal cant and intrusion and retraction of incisors, and may result in favorable functional movement of the jaw.

The application of a combined surgical-orthodontic procedure for the treatment of major facial deformities (eg, asymmetries) and associated malocclusions has become an increasingly prevalent treatment modality over the past few decades. Development of sound conjoint treatment principles made possible the correction of skeletal and dental dysplasias that were unyielding to either surgical or orthodontic treatment alone. The presence and severity of dentofacial asymmetries has been the subject of many commentaries and investigations. Treatment of facial asymmetry has always been a challenge with respect to the cause and the rationale behind the corrective procedures adopted. This case report describes a 23-year-old male patient whose chief complaint was attributed solely to the clinically discernible facial asymmetry. A combined orthodontic and surgical approach was done to correct both the dental and skeletal asymmetry. The reasons for selecting this treatment protocol and the 5-year postretention stability of the final results obtained are highlighted in this report.

Osteogenesis imperfecta is a bone disorder in which three factors that influence bone strength (quality, mass, and geometry of osseous tissue) are affected. Pneumatization refers to the development of air-filled cavities inside the bone. Knowledge about these air-filled cavities provides valuable information for understanding the diagnosis and spread of various pathologic entities like hemangiomas, giant cell tumors, eosinophilic granulomas, and even metastatic tumor deposits. This paper presents a case in which radiologic, clinical, biochemical, and karyotypic evaluations lead to a diagnosis of osteogenesis imperfecta.

Zimmermann-Laband syndrome (ZLS) is a rare autosomal disorder characterized by gingival fibromatosis, abnormalities of the nose and/or ears, hypoplasia of the nails or terminal phalanges of the hands and feet, hyperextensibility of joints, hepatosplenomegaly, hirsutism, and intellectual disability. The characteristics of the syndrome are highly variable and complicated. This paper reports a case of ZLS and the clinical manifestations encountered in relation to the current available literature. The comprehensive management of the patient's dentition is described, focusing on the orthodontic and surgical considerations clinicians should be aware of when treating patients with the syndrome.

Aim: The present study aimed to measure the magnitude of the collum angle (crown-root angulation) of maxillary central incisors present in Class II, division 2 malocclusion and to relate the changes in its magnitude with variations in the lower lip line.

Methods: A set of 120 conventional lateral cephalograms were selected and divided into three groups of 40 each based on the type of malocclusion presented: Class II, division 2 (group 1); Class II, division 1 (group 2); and Class I (group 3). The collum angle of the maxillary central incisor was measured, and the lower lip line was recorded.

Results: Analysis of variance (ANOVA) revealed that the mean collum angle was statistically significantly different in the three groups. The mean collum angle was greatest in Class II, division 2 malocclusion (group 1). The mean collum angles were 3.24 ± 4.69 degrees, 0.95 ± 1.06 degrees, and 1.05 ± 1.50 degrees in groups 1, 2, and 3 respectively. In χ ² test comparison of the location of the lower lip line (incisal, middle, or apical third of the central incisor) among the three groups, the lower lip line was found to contact the middle third of the central incisor most frequently in Class II, division 2 malocclusion. ANOVA followed by Tukey honestly significant difference (HSD) test showed that the mean collum angle is significantly increased when the lower lip is in the middle third (P < .05) of the central incisor.

Conclusion: Variations in magnitude of the collum angle with the change in the lower lip line suggest a probable etiologic role of the lower lip line in the development of the collum angle.

Aim: The purpose of this study was to investigate the salivary concentration of nickel and chromium of patients undergoing orthodontic treatment.

Methods: In this study 32 patients who presented to the orthodontic clinic were selected. The salivary samples were taken from the patients in four stages: before appliance placement and 20 days, 3 months, and 6 months following appliance placement. The salivary samples were collected in a plastic tube and were stored in the freezer before analysis. The samples were then transferred to the laboratory, and the amounts of metals were determined by graphite furnace atomic absorption spectrometry with an autosampler. Each sample was analyzed three times, and the average was reported.

Results: It was found that the average amount of nickel in the saliva 20 days after appliance placement was 0.8 μg/L more than before placement. Also, the amount of salivary nickel 20 days after the appliance placement was more than at the other stages, but the differences were not significant. The average amount of chromium in the saliva was found to be between 2.6 and 3.6 μg/L. The amount of chromium at all stages after appliance placement was more than before, but the differences between the chromium levels of saliva at all stages were not significant.

Conclusion: There was no significant difference in the average amount of salivary nickel and chromium of patients at various stages of orthodontic appliance placement.