Kun-Tsung Lee

Simple technique to achieve a natural head position for cephalography.

The cephalometric measurement of the face in terms of aesthetics can be difficult and misleading due to the variability of the intra-cranial reference lines according to diversity of head posture. Natural head position (NHP) has been proposed as a preferred reference position for assessing facial morphology. Even though natural head position is more proper and valid, it is still abandoned by reasons of time-consumption and additional and necessary complex equipment. Hence, we developed a modified level laser approach to acquire the natural head position. This method was a simple and straightforward technique which may be of value as and adjunct to routine orthognathic planning.

The perception of pain following interdental microimplant treatment for skeletal anchorage: a retrospective study

During orthodontic therapy, patients frequently complain about pain and discomfort, especially during insertion of fixed appliances. Skeletal anchorage using an interdental microimplant is a new concept in orthodontic treatment. The purpose of this study was to investigate differences and changes in the level of pain among patients in relation to orthodontic microimplant treatments. Forty microimplants were applied to the maxilla as skeletal anchors in the orthodontic treatment. The visual analog scale (VAS) was used to evaluate the patients’ perception of pain during this new modality treatment. The premolar extraction VAS core was used as a baseline for the complete orthodontic procedure. The mean VAS score was 35.8 mm at 24 h after premolar extraction. The mean VAS score for insertion and removal of the microimplant 24 h after the operation was 12.3 and 7.8 mm, respectively. Three months after removal of the skeletal anchors, the VAS score had decreased to 3.2 mm and was the same as with the traditional orthodontic treatment. By using the repeated-measure general linear model (GLM), we found that the score 1 day after microimplant placement was significantly less than that 1 day after first premolar extraction or that 1 day after fixed appliance insertion. This result indicates that interdental microimplant did not generate any greater pain than other orthodontic procedures. Therefore, patients were willing to adopt the new orthodontic treatment.

Correlation between the change of gonial region and skeletal relapse after intraoral vertical ramus osteotomy for correction of mandibular prognathism.

Background: The gonial region is coincided with harmonious face and masticatory function. The aims of the present study were to assess changes in the gonial region in patients who had mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) and to investigate the contributing factors in relation to skeletal relapse. Methods: Twenty-one patients with mandibular prognathism were corrected by IVRO. Three cephalometric radiographs were collected from preoperative orthodontic treatment (T1), immediately after surgery (T2), and at 2-year postoperative follow-up (T3). Relapse was defined as forward movement of menton (Me) after the 2-year follow-up. Three angular (SN-Go angle, mandibular plane angle, and gonial angle) and 2 linear (horizontal-Me and vertical-Me) measurements were compared after immediate operation and at the 2-year follow-up. Spearman rank correlation and Student t tests were used for statistical analysis. Results: The mean setback of the Me was 12.7 mm, and the mean relapse was 1.5 mm. The magnitude of setback was not significant for relapse. There were weak correlations between relapse and factors concerned with the gonial region (SN-Go angle, mandibular plane angle, and gonial angle). Conclusions: Surgical correction of mandibular prognathism using IVRO can lead to an increase in the angle changes of gonial region but not correlate to skeletal relapse in long-term follow-up.

PAIN PERCEPTION DURING MINIPLATE-ASSISTED ORTHODONTIC THERAPY

Miniplate and screw devices are widely used for fracture repair and fixation of osteotomies. Currently, these miniplate systems are being used as orthodontic treatments for skeletal anchorage. However, despite the widespread use of these treatments, patients are apprehensive when they need to undergo miniplate procedures. Recently, we assessed pain perception using the visual analog scale (VAS) score (0–100 mm) in patients who had undergone miniplate procedures. Thirty miniplates were positioned in the maxilla as skeletal anchors for orthodontic treatment. On the first day after insertion of the fixed orthodontic appliances, the mean VAS score was 36.3 mm. The mean VAS score at 24 hours after insertion of the miniplate was 58 mm. Three months after orthodontic force was applied to the miniplate, the mean VAS scores during eating and speaking gradually decreased to 20 mm and 15 mm, respectively. The mean VAS score at 24 hours after removal of the miniplate was 41.3 mm. Three months after removal of the skeletal anchors, the VAS score decreased to 5 mm. Eighty‐eight percent of patients stated that they would be prepared to undergo these new and more efficient treatment modalities in the future. The miniplate system was successfully used in this study as a skeletal anchor, and the patients could endure the pain and discomfort of this orthodontic treatment.

Interdisciplinary management of unfavorable posterior intermaxillary space

The patient was a case of severe dentoalveolar extrusion of the right maxillary posterior segment due to early loss of mandibular molars. Therefore, it is difficult to replace the missing teeth with either fixed or removable prostheses. Her occlusion was Angle Class II malocclusion and no mandibular molars for anchorage on the right side. A posterior maxillary subapical osteotomy was utilized for reestablishing the intermaxillary space. A titanium alloy miniplate placed in the right mandible provide skeletal anchorage to distalize the anterior mandibular teeth. Dental implants were placed to restore masticatory function.

Horizontal and vertical resistance strength of infrazygomatic mini-implants

This study assessed the adequacy of anchorage strength of infrazygomatic mini-implants in vertical and horizontal directions. Each brand of infrazygomatic mini-implant tested provided acceptable skeletal anchorage.

Mechanical strength of orthodontic infrazygomatic mini-implants

Orthodontic anchorages have recently been reinforced by newly developed mini-implants. The aim of the present study was to investigate the mechanical strengths of infrazygomatic mini-implants. We measured the insertion torque and pull-out strength of three brands of infrazygomatic mini-implants (AbsoAnchors, Bioray, and Lomas). All three mini-implants were 2 mm in diameter, and five of each brand were manually driven 6 mm into artificial bone. Significant differences among the brands were investigated with Kruskal-Wallis tests. We found no significant relationship between insertion torque and pull-out strength in any individual brand. Among the three brands of infrazygomatic mini-implants, we found no significant difference in mechanical strength. The design of an infrazygomatic mini-implant may be the most important factor determining its mechanical strength.

Proximal tibial bone harvesting under local anesthesia without intravenous sedation in the dental office: a case report.

Maxillary sinus enlargement often occurs in the maxillary posterior edentulous area and reduces the available bone height for implantation. Therefore, maxillary sinus lift and bone graft procedures are necessary to provide sufficient available bone. Autogenous bone grafting is the best base for implant osseointegration. Recently, tibial bone has been recognized as an alternative extraoral donor site. We present a case in which we used a proximal tibia bone graft for maxillary sinus augmentation under local anesthesia without sedation in the dental office. During a 4‐year postoperative follow‐up, gait was not disturbed and the scar on the donor site remained unremarkable.

Facial Cellulitis Arising from Dens Evaginatus: A Case Report

Dens evaginatus is a developmental anomaly that produces a tubercle on the occlusal surface of a tooth. It is found most frequently in the mandibular premolars. The occlusal tubercle easily causes occlusal interferences. Attrition or fracture of the tubercle can lead to pulpitis, pulp necrosis, periapical pathosis, and periapical infection. This case report illustrates the treatment of facial cellulitis arising from dens evaginatus with open apex. Calcium hydroxide was used for the apexification procedure. One year after canal obturation, radiography revealed no apical pathosis and the apical seal was evident.

Changes in the transverse dimensions by vertical ramus osteotomy after mandibular prognathism correction.

Objective: A harmonious face displays not only a good lateral profile but also a pleasant frontal appearance. The purpose of the current study was to evaluate the changes in the transverse dimensions by vertical ramus osteotomy (VRO) in the treatment of mandibular prognathism correction. Methods: Twenty patients who underwent mandibular prognathism correction by VRO were included. Lateral and frontal cephalometric radiographs were obtained at the following stages: preoperative (T1), immediately after the surgery (T2), and completion of orthodontic treatment (T3). Three linear measurements (menton, intercondylion, and intergonial distances) and the ramus angle were compared from T1 to T3. Results: A final mean menton setback of 12.2 mm and upward movement of 0.3 mm were noted. The intercondylion and intergonial distances significantly increased by 5.1 and 7.1 mm, respectively. Without significant difference, ramus angles decreased 1.7 degrees in the right side and 0.1 degrees in the left side. Conclusion: The surgical correction of mandibular prognathism using VRO led to an increase in the transverse dimensions.