Correcting severe scissor bite in an adult.

Scissor bite often remains unnoticed by patients although it can adversely affect facial symmetry, jaw growth, and mastication. This case report illustrates the efficacy of temporary skeletal anchorage devices (TSADs) and a modified lingual arch in correcting severe scissor bite. A 28-year-old woman presented with severe scissor bite in the mandibular right posterior segment. To treat this condition, TSADs were used for maxillary posterior intrusion and a modified lingual arch for buccally uprighting mandibular posterior teeth. Long-term retention records demonstrate stable treatment results.

Change in alveolar bone level of mandibular second and third molars after second molar protraction into missing first molar or second premolar space.

OBJECTIVE: To investigate the factors associated with the change in alveolar bone level of mandibular second and third molars after second molar protraction into the space of the missing first molar (L6) or second premolar (LE). METHODS: Fifty-one patients in whom space of the missing L6 or LE was treated with second molar protraction (13 males, 38 females, mean age 19.6 ± 4.7 years) from 2003 to 2015 were included. The alveolar bone level and position and angulation of the mandibular second and third molars were measured in panoramic radiographs at pre-treatment (T1), and after the alignment of the third molars following second molar protraction (T2). Factors associated with alveolar bone loss on the distal aspect of the mandibular second molars were assessed using linear regression analysis. RESULTS: Age at T1 (P < 0.001) and third molar angulation at T1 (P = 0.002) were significant factors for the prediction of alveolar bone level distal to the second molars. LIMITATION: This study used two-dimensional panoramic radiographs, and we could observe only the interproximal bone level. CONCLUSIONS: After second molar protraction into the missing first molar or second premolar space, mandibular second molars may exhibit alveolar bone resorption in the distal root in older patients and in those with mesially tilted third molars before treatment.

Envisioning Post-treatment Occlusions after Space Closure Using Temporary Skeletal Anchorage Devices.

Missing posterior teeth and posterior tooth extractions are commonly seen and needed within orthodontic practices. With the invention of temporary skeletal anchorage devices (TSADs), clinicians can now effectively close posterior tooth spaces. Various molar occlusions are discussed to help clinicians envision post-treatment occlusions after posterior teeth space closure using TSADs.

Nonextraction treatment with temporary skeletal anchorage devices to correct a Class II Division 2 malocclusion with excessive gingival display.

The patient was a 22-year-old Japanese woman who complained of a gummy smile. She had several other orthodontic problems, including crowding of the maxillary anterior teeth, retroclination of the maxillary central incisors, excessive maxillary incisor display, a deep overbite, Class II dental relationships, a Class II profile, and a long face. Two options for the correction of these problems were proposed. The first option was to extract the maxillary first premolars to correct the Class II relationship and implant a miniscrew to correct the gingival display; the second option was to place 2 miniplates for distalization of the maxillary molars and a miniscrew to correct the gingival smile without premolar extractions. The patient chose the second option. After placing a preadjusted bracketed system, 2 miniplates were placed in the zygomatic buttresses bilaterally with monocortical screws, and 1 miniscrew was fixed between the root apices of the maxillary central incisors. Distalization and intrusion of the maxillary molars and intrusion of the maxillary incisors were simultaneously started with those temporary skeletal anchorage devices functioning as absolute orthodontic anchors. The total treatment period was approximately 22 months. Her orthodontic problems were corrected. According to the cephalometric evaluation, the entire maxillary dentition was significantly distalized, and her maxillary incisors were successfully intruded, with the mandible showing a slight counterclockwise rotation. Thanks to the temporary anchorage devices combined with miniplates and a miniscrew, we were able to predictably achieve her treatment goals without premolar extractions, orthognathic surgery, and the need for patient compliance.

One-phase vs 2-phase treatment for developing Class III malocclusion: a comparison of identical twins.

Despite the known influence of early treatment on the facial appearance of growing patients with skeletal Class III malocclusion, few comparative reports on the long-term effects of different treatment regimens (1-phase vs 2-phase treatment) have been published. Uncertainty remains regarding the effects of early intervention on jaw growth and its effectiveness and efficiency in the long term. In this case report, we compared the effects of early orthodontic intervention as the first phase of a 2-phase treatment vs 1-phase fixed appliance treatment in identical twins over a period of 11 years. Facial and dental changes were recorded, and cephalometric superimpositions were made at 4 time points. In spite of the different treatment approaches, both patients showed identical dentofacial characteristics in the retention phase. Through this case report, we intended to clarify the benefits of undergoing 1-phase treatment against 2-phase treatment protocols for treating growing skeletal Class III patients.

Protraction of mandibular second and third molars into missing first molar spaces for a patient with an anterior open bite and anterior spacing.

In a young woman, aged 18 years 8 months, who had an anterior open bite and anterior spacing, the right and left mandibular first molar extraction spaces were closed by protraction of the second and third molars without reciprocal retraction of the incisors and the premolars. The amounts of protraction for the second molars were 12 mm on the right side and 11 mm on the left side. Two miniscrews were inserted into the mesiobuccal side of the edentulous spaces, and 2 more screws were inserted into the anterior sites after removing previous miniscrews. In addition, 4 miniscrews were inserted into the buccal and palatal sides between the first and second maxillary molars to intrude the maxillary posterior teeth, which had extruded into the missing mandibular spaces. Careful biomechanical consideration was used to prevent extrusion of the molars and worsening of the anterior open bite from protraction of the posterior teeth. Ultimately, the anterior open bite was corrected by both intrusion of the maxillary molars and extrusion of the maxillary anterior teeth. Excellent occlusion and correction of the anterior open bite were achieved without tipping, rotation of the posterior teeth, or other problems. The right mandibular third molar, which had been impacted at the beginning of treatment, erupted into the second molar space and functioned properly. At the 1-year follow-up examination, the patient had a slight anterior open bite, but closure of the first molar extraction spaces was well maintained.

A new rationale for preservation of the mandibular third molar in orthognathic patients with missing molars.

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

Effect of "surgery first" orthognathic approach on temporomandibular symptoms and function: a comparison with "orthodontic first" approach.

OBJECTIVE: The aim of this study was to comparatively evaluate the effects of the surgery-first approach (SFA) and the orthodontics-first approach (OFA) on temporomandibular joint (TMJ) function and maximum mouth opening. STUDY DESIGN: This retrospective study investigated the outcomes of patients with diagnosed skeletal class III dentofacial deformities. Twenty-four patients were enrolled in the OFA group, and 23 patients were enrolled in the SFA group. All patients were examined in the same manner 4 times: before surgery and at 1, 3, 6, and 12 months after surgery. Range of mouth opening (ROM) was measured between the maxillary and mandibular central incisors. Symptoms were evaluated subjectively by using a questionnaire with items pertaining to pain on mandibular movements, TMJ sounds, and pain in masticatory muscles region. RESULTS: No severe complications or relapse occurred in either group during the 12-month follow-up period. Postoperative changes in ROM showed similar tendencies, but there was no significant difference in ROM during the follow-up period between the OFA and SFA groups (P < .05). The percentage reduction was nearly 45% at 1 month postoperatively and 20% at 3 months postoperatively compared with the preoperative situation. After 6 months postoperatively, the ROM was almost the same as before surgery. The number of patients with such sounds increased with time until 12-month postoperative examinations in the OFA group but increased slightly during this period in the SFA group. During the first 3 months postoperatively, less than 10% of patients in both groups had newly detected pain of TMJ and/or muscles. At 6 and 12 months postoperatively, only 1 patient in the SFA group had pain. CONCLUSIONS: No significant differences in TMJ symptoms or function were observed during a 12-month follow-up period between patients with skeletal class III malocclusion treated with the SFA and those treated with the OFA.

Success rates of a skeletal anchorage system in orthodontics: A retrospective analysis.

OBJECTIVES: To evaluate the premise that skeletal anchorage with SAS miniplates are highly successful and predictable for a range of complex orthodontic movements. MATERIALS AND METHODS: This retrospective cross-sectional analysis consisted of 421 bone plates placed by one clinician in 163 patients (95 female, 68 male, mean age 29.4 years ± 12.02). Simple descriptive statistics were performed for a wide range of malocclusions and desired movements to obtain success, complication, and failure rates. RESULTS: The success rate of skeletal anchorage system miniplates was 98.6%, where approximately 40% of cases experienced mild complications. The most common complication was soft tissue inflammation, which was amenable to focused oral hygiene and antiseptic rinses. Infection occurred in approximately 15% of patients where there was a statistically significant correlation with poor oral hygiene. The most common movements were distalization and intrusion of teeth. More than a third of the cases involved complex movements in more than one plane of space. CONCLUSIONS: The success rate of skeletal anchorage system miniplates is high and predictable for a wide range of complex orthodontic movements.

Photoelastic stress analysis of mandibular molars moved distally with the skeletal anchorage system.

INTRODUCTION: The purpose of this study was to analyze photoelastically the stress distribution around teeth in the simulated distal movement of mandibular molars with the skeletal anchorage system. METHODS: Two types of the photoelastic mandibular dentition models were used, 1 before and 1 after distal movement of the second molar. The experiment was performed with 3 forms of traction--first-molar single traction, second-molar single traction, and simultaneous first- and second-molar traction. The direction of traction was set parallel to the occlusal plane and at an angle of 30 degrees downward to the occlusal plane. RESULTS: In the first-molar single traction model, extremely high stress was generated around the first molar with traction parallel to the occlusal plane. With the traction 30 degrees downward to the occlusal plane, all models showed the stress around the molars extended distally and downward. CONCLUSIONS: Simultaneous traction of the first and second molars might be preferable to the sequential traction of each molar to prevent the unfavorable distal tipping of the first molar. Regardless of whether simultaneous or sequential traction is used, the downward traction to the occlusal plane seems to induce intrusion of the molars as well as their distal movement.

Remodeling of alveolar bone crest after molar intrusion with skeletal anchorage system in dogs.

INTRODUCTION: The aim of this study was to clarify the influence of supra-alveolar fibers on alveolar bone crest remodeling when several teeth are intruded simultaneously. METHODS: The skeletal anchorage system was used to bilaterally intrude the second and third premolars of 10 beagles; supracrestal fiberotomies were performed on 1 side only. RESULTS: The amount of intrusion was greater and the amount of alveolar bone resorption was smaller in the fiberotomy group compared with the nonfiberotomy group. The health status (pocket depth <3 mm) of the dentogingival unit was maintained in the nonfiberotomy group during the experimental period. In the fiberotomy group, the number of osteoclasts on the marginal alveolar crest was less than in the nonfiberotomy group. The dense fiber bundles connecting the second and third premolars and the gingival attachments were maintained in the nonfiberotomy group. CONCLUSIONS: Pressure from the supra-alveolar fibers generated by segmental molar intrusion with the skeletal anchorage system induced alveolar bone crest resorption and remodeling, and, as a result, it prevented deepening of the gingival pocket. Periodontal status was good during tooth intrusion.

Morphologic and hemodynamic analysis of dental pulp in dogs after molar intrusion with the skeletal anchorage system.

INTRODUCTION: We have successfully treated skeletal open bite by intruding posterior teeth with the skeletal anchorage system. Our aim in this study was to morphologically and hemodynamically evaluate the changes in pulp tissues when molars are radically intruded. METHODS: The mandibular fourth premolars of 9 adult beagle dogs were divided into 3 groups: a sham operated group (n = 6, 3 dogs), 4-month intrusion group (n = 6, 3 dogs), and a further 4-month retention group (n = 6, 3 dogs). We evaluated the morphological changes of the pulp and dentin-the amount of vacuolar degeneration in the odontoblast layer, the predentin width and nervous continuity in the pulp tissue, and the pulpal blood-flow response evoked by electrical stimulation in the dental pulp. RESULTS: Extreme molar intrusion with the skeletal anchorage system caused slight degenerative changes in the pulp tissue, followed by recovery after the orthodontic force was released. Circulatory system and nervous functions were basically maintained during the intrusion, although a certain level of downregulation was observed. These morphologic and functional regressive changes in the pulp tissue after molar intrusion improved during the retention period. CONCLUSIONS: Histologic changes and changes in pulpal blood flow and function are reversible, even during radical intrusion of molars.

Mandibular widening by intraoral distraction osteogenesis for severe telescopic bite correction: a report of 2 cases.

Two patients with telescopic bites due to narrow mandibular arches were treated by mandibular widening and mandibular lengthening with intraoral distraction osteogenesis. Both patients underwent distraction osteogenesis surgery successfully, without any complications. The amount of widening in the 2 cases was 6 mm and 5 mm, and the intercanine distance increased by 2.1 mm and 4.9 mm, respectively. Nonextraction orthodontic treatment was performed after removal of the distraction devices in both cases. The postsurgical orthodontic treatment periods of the 2 cases were 13 months and 7 months, respectively. Eventually, functional occlusions and good profiles were obtained in both cases. Although both patients complained of temporomandibular joint symptoms at the first consultation, those symptoms were improved after treatment. At 3 years after debonding, dentofacial relapse was negligible. In conclusion, mandibular widening by intraoral distraction osteogenesis appeared to be an effective modality for correcting telescopic bites.

Morphologic analyses of mandible and upper airway soft tissue by MRI of patients with obstructive sleep apnea hypopnea syndrome.

STUDY OBJECTIVES: To evaluate the morphological features of the mandible and the volume of the upper airway soft tissues in determining the anatomical risk factors for the upper airway in Japanese male patients with obstructive sleep apnea hypopnea syndrome (OSAHS). METHODS: Five morphological parameters of the mandible at the mandibular base plane and three volumetric parameters of the upper airway soft tissue were analyzed using three-dimensional (3D) magnetic resonance imaging software in 31 OSAHS and 20 controls. RESULTS: There were no significant differences between the two groups in mandibular internal width (the distance between the internal right and left gonia [IRG and ILG]) and mandibular bony thickness. However, the patients with OSAHS had a significantly wider mandibular divergence (the angle between the spina mentalis (SM)- IRG line and SM- ILG line), a smaller mandibular internal length (the perpendicular distance from SM to the RG- LG line), and a smaller area than the normal subjects at the mandibular base plane. There were no significant differences in these morphological parameters for the mandible between obese and nonobese OSAHS patients. The volumes of the tongue, soft palate, and lateral pharyngeal walls were not significantly different between the OSAHS and the control groups. CONCLUSIONS: Japanese male OSAHS patients had specific anatomical features in the bottom part of the mandible; however, obesity seemed to be a less significant risk factor. Investigators and clinicians must realize that ethnicity may modify the effects of obesity and abnormal craniofacial anatomy as risk factors for the pathogenesis of OSAHS.

Distal movement of maxillary molars in nongrowing patients with the skeletal anchorage system.

INTRODUCTION: It is now possible to predictably move maxillary molars distally in nongrowing patients with the skeletal anchorage system (SAS) and to improve malocclusions without having to extract the premolars and regardless of the patient's compliance. The purposes of this study were to investigate the amount of distal movement of the maxillary first molars, the type of movement, the difference between actual and predicted amounts of distalization, and the relationship between the amount of distalization and age. METHODS: Twenty-five nongrowing patients (22 female, 3 male) successfully treated with the SAS were the subjects in this study. The amount and the type of distalization, the difference between predicted and resulting amounts of distalization, and the relationship between the patient's age and the amount of distalization were analyzed with wide-opening cephalometric radiographs. RESULTS: The average amount of distalization of the maxillary first molars was 3.78 mm at the crown level and 3.20 mm at the root level. The amount of distalization at the crown level was significantly correlated with the average value of treatment goals (3.60 mm). CONCLUSIONS: The maxillary molars were predictably distalized in accordance with the individualized treatment goals without regard to patient age and extraction of the third or second molars. The SAS is a viable noncompliance modality to move maxillary molars for distally correcting maxillary protrusions and malocclusions characterized by maxillary incisor crowding.

Linear and angular filipino cephalometric norms according to age and sex.

OBJECTIVE: To quantify relevant cephalometric parameters for Filipinos according to age and sex. MATERIALS AND METHODS: A total of 157 Filipino subjects (78 males, 79 females) who fulfilled specific criteria were selected from elementary, high school, and college students affiliated with Manila Central University. They were divided into comparison groups (GI, GII, GIII, and GIV) on the basis of chronological age and sex. Lateral cephalograms were taken for all subjects, and the mean and standard deviation for each parameter was recorded and compared among groups. RESULTS: The male group had a longer anterior cranial base (S-N), total facial height (N-Me), longer lower anterior facial height (N-ANS), longer ramus height (Cd-Go), longer lower posterior dentoalveolar height (Mo-Mi'), and total mandibular length (Gn-Cd) than the female group. All these linear measurements were statistically significantly different between males and females in GI, GIII, and GIV. On the other hand, SNB angle showed significant differences (P = .0271) in GIV only. In the lower third of the face, significant opposite tendencies were found in GIV. The female group showed a clockwise rotation, whereas the male counterpart had a counterclockwise rotation of the mandibular plane. The denture pattern of both groups was characterized by a proclination of both lower incisor (Ii to MP) and upper incisor (Is to SN). CONCLUSIONS: Convexity due to dentoalveolar protrusion is the naturally occurring facial profile for Filipinos. The adult females showed steeper mandibular and occlusal plane angles than the male samples.