Open-bite closure by intruding maxillary molars with skeletal anchorage

Most anterior open bite cases are characterized by the excessive vertical development of the posterior maxilla. Intrusion of the overerupted molar teeth with traditional orthodontic methods is hardly possible; therefore, there is no real alternative to a combined orthodontic and surgical approach. Skeletal anchorage has recently been offered for the orthodontic movement of teeth. Titanium miniplates implanted in the zygomatic buttress area can serve as absolute anchorage for maxillary molar intrusion. The aim of this study was to evaluate skeletal anchorage for closing open-bite malocclusions. Seven patients with severe anterior open-bites were selected. In all cases the deformity was due to the overeruption of the maxillary molars. Titanium miniplates were inserted bilaterally in the zygomatic buttress region. Fixation was performed with 3 miniscrews. Elastic bands or coil springs were used to reduce excessive maxillary molar heights. The mean active treatment time was 6 months. In all cases the anterior open-bite significantly improved. No side-effects were observed. Our results suggest that skeletal anchor plates offer successful treatment for closing skeletal anterior open bites.     

The influences of molar intrusion on the inferior alveolar neurovascular bundle and root using the skeletal anchorage system in dogs

The skeletal anchorage system (SAS) was developed as intraoral rigid anchors for open-bite correction by intrusion of molars. Since the application of SAS is a new modality in orthodontic treatment, the influences of radical molar intrusion on the root and the inferior alveolar neurovascular bundle were unknown. The purpose of this research is to verify the effect of molar intrusion on the neurovascular bundle, the level of osseointegration of bone screws, and root resorption. The results of this study showed mandibular molars were intruded 3.4 mm on the average over 7 months in dogs. The miniplates were well stabilized with osseointegrated bone screws and the peri-implant soft tissues showed slight inflammatory changes. Neither nerves nor blood vessels were damaged. Root resorption was observed but was repaired with new cementum. We concluded that the SAS utilizing transmucosal titanium miniplates as an immovable orthodontic anchorage could provide a new modality for molar intrusions without serious iatrogenic problems.     

Skeletal anchorage system for open-bite correction

A skeletal anchorage system was developed for tooth movements. It consists of a titanium miniplate that is temporarily implanted in the maxilla or the mandible as an immobile anchorage. In this article, we introduce the skeletal anchorage system to intrude the lower molars in open-bite malocclusion and evaluate the results of treatment in two severe open-bite cases that underwent orthodontic treatment with the system. Titanium miniplates were fixed at the buccal cortical bone around the apical regions of the lower first and second molars on both the right and left sides. Elastic threads were used as a source of orthodontic force to reduce excessive molar height. The lower molars were intruded about 3 to 5 mm, and open-bite was significantly improved with little if any extrusion of the lower incisors. No serious side-effects were observed during the orthodontic treatment. The system was also very effective for controlling the cant and level of the occlusal plane during orthodontic open-bite correction. (Am J Orthod Dentofacial Orthop 1999;115:166-74)     

The use of skeletal anchorage in open bite treatment: a cephalometric evaluation

The aims of the present study were to assess the effectiveness of skeletal anchorage for intrusion of maxillary posterior teeth, to correct open bite malocclusion, and to evaluate the usage of titanium miniplates for orthodontic anchorage. Anterior open bite is one of the most difficult malocclusions to treat orthodontically. Currently, surgical impaction of the maxillary posterior segment is considered to be the most effective treatment option in adult patients. Various studies have reported the use of implants as anchorage units at different sites of midfacial bones for orthodontic tooth movement. The zygomatic buttress area could be a valuable anchorage site to achieve intrusion of maxillary posterior teeth. Ten patients, 17 to 23 years old and characterized with an anterior open bite and excessive maxillary posterior growth, were included in this preliminary study. Titanium miniplates were fixed bilaterally to the zygomatic buttress area, and a force was applied bilaterally with nine mm Ni-Ti coil springs between the vertical extension of the miniplate and the first molar buccal tube. The results showed that, with the help of skeletal anchorage, maxillary posterior teeth were intruded effectively. As compared with an osteotomy, this minimally invasive surgical procedure eased treatment and reduced treatment time and did not require headgear wear or anterior box elastics for anterior open bite correction. In conclusion, the zygomatic area was found to be a useful anchorage site for intrusion of the molars in a short period of time.     

Intrusion of overerupted upper first molar using two orthodontic miniscrews. A case report

Loss of the mandibular first molar often leads to the overeruption of the opposing maxillary first molar, resulting in occlusal interference, loss of periodontal bony support, and inadequate room to restore the mandibular edentulous space. Without orthodontic molar intrusion or segmental surgical impaction, restoring the posterior occlusion often entails the need for significant reduction of maxillary molar crown height, with the potential need for costly iatrogenic root canal therapy and restoration. The literature has cited successful maxillary molar intrusion with minor prosthodontic reduction using palatal orthodontic miniscrews and buccal zygomatic miniplates. In this report, the authors present successful maxillary molar intrusion with two orthodontic miniscrews in a patient with extreme dental anxiety and significant dental erosion due to gastric reflux. Using two orthodontic miniscrews for skeletal anchorage to intrude the maxillary molar simplified the orthodontic treatment by eliminating the need for extensive surgery, headgear, and intraoral multiunit anchorage and preserved indispensable tooth enamel. The clinical results showed significant intrusion through the maxillary sinus cortical floor while maintaining periodontal health, tooth vitality, and root length.     

Closing anterior open bites by intruding molars with titanium miniplate anchorage

The intent of this study was threefold: (1) to validate true intrusion of molars in adults, (2) to test the stability of miniplates as anchorage for intruding posterior teeth in the maxilla, and (3) to record the skeletal and dental changes of open-bite closure. Four adult patients who had anterior open-bite malocclusions were selected to undergo posterior intrusion with miniplate anchorage to close the open bite; all had true intrusion of the maxillary molars. Mean molar intrusion was 1.99 mm (range, 1.45-3.32 mm). No movement of miniplates occurred at any time during their use or before intentional clinical removal. Open-bite closure was achieved for all 4 patients. Mean closure of incisors was 3.62 mm (range, 3.0-4.5 mm) as the mandibular plane closed 2.62 degrees (range, 1.5 degrees -4.5 degrees ), and the occlusal plane decreased 2.25 degrees (range, 1.0 degrees -3.5 degrees ). Anterior facial heights decreased as the mandible closed and B-point rotated anteriorly and upward.     

Osteotomy assisted maxillary posterior impaction with miniplate anchorage

This case report presents orthodontic treatment with miniplate anchorage accelerated by osteotomy-assisted maxillary posterior impaction in a severe open bite case. A 14-year-old girl with a severe anterior open bite was treated by intrusion of the maxillary posterior teeth. A segmental osteotomy was applied, and the miniplates were fixed to the zygomatic buttress area. The intrusive force was applied with nickel-titanium closed coil springs using a force of 250 g between the miniplates and the upper first and second molar buccal tubes. The intrusion was completed 2.5 months after osteotomy. The treatment was continued with the fixed orthodontic appliances and completed after 12 months. At the end of treatment, optimal occlusion and the correction of the anterior open bite were achieved. The maxillary molars were impacted 4.0 mm, and the mandibular plane showed a counterclockwise autorotation of 3.0 degrees . The results showed that osteotomy-facilitated orthodontic treatment clearly reduced the treatment time and had no adverse effects. In conclusion, this one-stage osteotomy technique can be an effective option to help molar intrusion in severe open bite cases.     

An adult bimaxillary protrusion treated with corticotomy-facilitated orthodontics and titanium miniplates

We performed an orthodontic treatment combined with corticotomy and the placement of titanium miniplates in an adult patient who desired a shortened treatment period. The patient had an Angle Class I malocclusion with flaring of the maxillary and mandibular incisors. First, titanium miniplates were placed into the buccal alveolar bone of the maxilla for absolute orthodontic anchorage. Second, an edgewise appliance was applied to the maxillary and mandibular teeth. Then, the maxillary first premolars and mandibular second premolars were extracted. At the same time, a corticotomy was performed on the cortical bone of the lingual and buccal sides in the maxillary anterior as well as the mandibular anterior and posterior regions. Leveling was initiated immediately after the corticotomy. The extraction spaces were closed with conventional orthodontic force (approximately 1 N per side). The edgewise appliance was adjusted once every 2 weeks. The total treatment time was 1 year. Cephalometric superimpositions showed no anchorage loss, and panoramic radiographs showed neither significant reduction in the crest bone height nor marked apical root resorption. A corticotomy-facilitated orthodontic treatment with titanium miniplates might shorten an orthodontic treatment period without any anchorage loss or adverse effects.     

Effects of maxillary molar intrusion on the nasal floor and tooth root using the skeletal anchorage system in dogs

The skeletal anchorage system (SAS) was developed to provide intraoral absolute anchorage for the intrusion or distalization of molars. The purpose of this study was to verify the effects of remarkable molar intrusion on the tooth root and the maxillary sinus floor. Six adult female beagles with fully erupted dentition were used. Titanium miniplates were implanted bilaterally above the maxillary second premolar root apices using pentobarbital anesthesia. The second premolars were intruded for four or seven months after three months of healing after implantation. Standardized dental radiographs were taken periodically to evaluate the amount of tooth movement and root resorption. After the experimental animals were fixed by perfusion at the end of each experimental period, the second premolars were dissected along with the surrounding alveolar bone. Undecalcified (60 microm thick) and decalcified (five microm thick) sections were prepared. The average extent of intrusion was 1.8 mm after four months and 4.2 mm after seven months. The root apices of the intruded molars penetrated into the nasal cavity. Remodeled bone around the intruded molar toots was rich in woven bone on the buccal side, whereas that on the palatal side was rich in lamellar bone. Nasal floor membrane and a thin layer of newly formed bone, which lifted intranasally, covered the intruded molar root. Root resorption partly reached into the dentine without the formation of reparative cementum, and little or no serious pathological changes were seen in the pulp of the intruded molars. SAS effectively intruded maxillary molars, but some moderate root resorption was observed.     

Intrusion of overerupted molars by corticotomy and orthodontic skeletal anchorage

This article describes the orthodontic treatment of a 26-year-old female patient with overerupted left maxillary molar teeth. Her chief complaint was that the maxillary left first and the second molar intruded into the space required for the mandibular left first and the second molars, preventing prosthodontic treatment. The authors performed a corticotomy and used orthodontic skeletal anchorage with a miniplate and orthodontic miniscrews with a head modified to provide a specially designed hook. With this approach, they were able to achieve a sufficient amount of molar intrusion without discomfort, root resorption, or extrusion of the adjacent teeth. The first molar was intruded 3.0 mm and second molar was intruded 3.5 mm during 2 months of treatment. These results have been maintained for 11 months.     

Skeletal anchorage for orthodontic correction of severe maxillary protrusion after previous orthodontic treatment

The correction of a severe maxillary protrusion in an adult by distal movement of the maxillary molars has been one of the most difficult biomechanical problems in orthodontics. This article reports on the treatment of an adult case of severe maxillary protrusion and a large overjet treated with a skeletal anchorage system. A female patient, age 22 years and 3 months, complained of the difficulty of lip closure due to severe maxillary protrusion with a gummy smile. Overjet and overbite were +7.6 mm and -0.9 mm, respectively. She had a history of orthodontic treatment in which her maxillary first premolars were extracted. In order to conduct distal movement of the maxillary molars, anchor plates were placed in the zygomatic process. After achieving a Class I molar relationship, retraction and intrusion of the maxillary incisors were performed. After a 2-year treatment, an acceptable occlusion was achieved with a Class I molar relationship. Her convex facial profile with upper lip protrusion was considerably improved, and the lips showed less tension in lip closure. After a 2-year retention period, an acceptable occlusion was maintained without recurrence of maxillary protrusion, indicating a stability of the occlusion. The result of this treatment indicated that skeletal anchorage is of great importance as a remedy for achieving intrusion and retraction of the maxillary incisors in cases of severe maxillary protrusion with a patient who had previous orthodontic treatment.     

新型压低下颌磨牙矫治器的临床应用

目的 评估新型压低下颌磨牙矫治器压低下颌磨牙的疗效及应用价值.方法 选择7例需要压低下颌磨牙治疗的前牙开患者,治疗前、后通过临床检查、牙颌模型分析及采用Winceph7.0数字化X线片分析软件测量头颅侧位片,评价临床压入效果,使用SPSS 17.0统计软件包对数据进行分析.结果 7例患者经过平均4个月的治疗,均取得比较明显的治疗效果.治疗前、后头影测量分析表明:下颌第一磨牙的平均压入量为(1.92±0.44)mm,矫治前、后相对于基准平面(MP平面)的垂直距离差异有统计学意义(P<0.05).上颌第一磨牙平均压入量为(0.36±0.25)mm,矫治前、后相对于基准平面(PP平面)的垂直距离差异没有统计学意义(P>0.05).X片显示被压低的下颌磨牙未出现明显的牙根吸收.结论 新型下颌磨牙压低矫治器用于压入下颌磨牙治疗前牙开畸形效果明显,压入治疗未引起明显的牙周及牙根损害.     

种植体支抗压低过长磨牙的临床效果分析

目的探讨使用种植体支抗压低过长上颌磨牙的临床效果。方法使用微螺钉种植体支抗配合部分或全口矫治器压低13例患者的过长上颌磨牙（共23颗），其中第一磨牙15颗、第二磨牙7颗、第三磨牙1颗。在头颅侧位片上测量磨牙近、远中边缘嵴至腭平面的垂直距离，配对t检验比较治疗前后的差异。结果压低过长磨牙的矫治疗程为5～18个月，平均10．4个月。头影测量结果显示磨牙压低0．45～7．00mm，平均（2．86±1．80）mm，治疗前后磨牙近中和远中边缘嵴至腭平面垂直距离的差异均有统计学意义（P〈0．001）。X线片显示牙槽骨高度无改变，根尖无明显吸收。结论以微螺钉种植体作为支抗压低过长上颌磨牙，是一种有效的治疗方法。     

正畸治疗中磨牙的拔除和保留(十四)——关闭陈旧性和非陈旧性磨牙间隙对牙根吸收的影响研究

目的：对比研究正畸关闭陈旧性和非陈旧性磨牙间隙病例的牙根吸收情况，探讨关闭不同缺失时间的下颌第一磨牙缺隙对第二磨牙牙根吸收的影响。方法：25例存在下颌第一磨牙缺隙的患者为研究对象，按第一磨牙缺失时间不同分成2组。将研究病例矫治前后下颌第二磨牙的冠根比作配对t检验，判断其牙根吸收程度。结果：矫治后较矫治前两组均发生牙根吸收，关闭陈旧性磨牙间隙组牙根吸收程度较非陈旧性组大，但二组间差别无显著性。结论：正畸关闭陈旧性磨牙间隙并不会加重磨牙牙根的吸收。     

Long-term stability of soft tissue changes in anterior open bite adults treated with zygomatic miniplate-anchored maxillary posterior intrusion

Objectives:To evaluate soft tissue changes and their long-term stability in skeletal anterior open bite adults treated by maxillary posterior teeth intrusion using zygomatic miniplates and premolar extractions.Materials and Methods:Lateral cephalograms of 26 patients were taken at pretreatment (T1), posttreatment (T2), 1 year posttreatment (T3), and 4 years posttreatment (T4).Results:At the end of treatment, the soft tissue facial height and profile convexity were reduced. The lips increased in length and thickness, with backward movement of the upper lip and forward movement of the lower lip. The total relapse rate ranged from 20.2% to 31.1%. At 4 years posttreatment, 68.9% to 79.8% of the soft tissue treatment effects were stable. The changes in the first year posttreatment accounted for approximately 70% of the total relapse.Conclusions:Soft tissue changes following maxillary posterior teeth intrusion with zygomatic miniplates and premolar extractions appear to be stable 4 years after treatment.     

Severe anterior open-bite case treated using titanium screw anchorage

Anterior open bite is often caused by a downward rotation of the mandible and/or by excessive eruption of the posterior teeth. In such cases, it is difficult to establish absolute anchorage for molar intrusion by traditional orthodontic mechanics. This article reports the successful treatment of a severe skeletal anterior open-bite case using titanium screw anchorage. A female patient 33 years eight months of age had open bite of -7.0 mm and increased facial height. The titanium screws were implanted in both the maxilla and the mandible, and an intrusion force was provided with elastic chains for 13 months. After active treatment of 19 months, her upper and lower first molars were intruded about 3.0 mm each, and good occlusion was achieved. Her retrognathic chin and convex profiles were improved by an upward rotation of the mandible. Our results suggest that titanium screws are useful for intrusion of molars in anterior open-bite cases.     

A Simple Way to Intrude Overerupted Upper Second Molars with Miniscrews

Various methods of using skeletal anchorage for the intrusion of overerupted maxillary molars have been reported; however, it is difficult to intrude the overerupted upper second molars because of the low bone density in the region of the tuberosity. This article illustrates a new treatment method using partial fixed edgewise appliances and miniscrews to intrude the overerupted upper second molars. The miniscrews were applied to reinforce the anchorage of the upper first molar. The intrusive force was generated by the Ni‐Ti wire. The clinical results showed a significant intrusion effect without root resorption or periodontal problems. This report demonstrates that the combination of partial conventional fixed appliances with miniscrews is a simple and effective treatment option to intrude overerupted upper second molars, especially in situations where miniscrews cannot be inserted directly next to the second molar.     

Root resorption after orthodontic intrusion and extrusion: an intraindividual study

The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight weeks. Eleven maxillary first premolars from six randomly selected orthodontic patients served as controls. Root resorption was determined using scanning electron microscopy. Quantitative assessment of the percentage of resorbed area of the total root surface was performed on composite micrographs. The severity of root resorption was also assessed by visual scoring of the roots. Root resorption mainly occurred at the apical part of the roots in both experimental groups. A significant difference in root resorption was found between the intruded and the control teeth (P = .006) but not between the extruded and the control teeth. However, the mesial and distal root surfaces showed resorption on 5.78 +/- 3.86% of the root surface of the intruded teeth and 1.28 +/- 1.24% of the root surface of the extruded teeth, and this difference was significant (P = .004). In addition, a large individual variation was found. From this study, it can be concluded that intrusion of teeth causes about four times more root resorption than extrusion. Because the amount of root resorption due to intrusion or extrusion in the same patient is correlated, every clinician should be aware that the extrusion of teeth might also cause root resorption in susceptible patients.     

Skeletal anchorage for orthodontic correction of maxillary protrusion with adult periodontitis

Because the number of adult patients seeking orthodontic treatment is increasing, orthodontists are becoming more likely to encounter patients with adult periodontitis. However, it is sometimes difficult to establish anchorage because of poor periodontal tissues in patients with adult periodontitis. This article reports the successful use of skeletal anchorage to treat a maxillary protrusion case complicated by severe adult periodontitis. A female patient aged 50 years seven months showed a skeletal Class II jaw base relationship. A spacing of five mm in the upper anterior teeth with an overjet of 7.5 mm and overbite of four mm was observed. She had generalized horizontal bone loss in both arches, with vertical bone loss in the posterior segment. After periodontal treatment, miniplates were placed in the zygomatic process, and retraction and intrusion of the maxillary incisors were performed. After active treatment for 21 months, the upper incisors had been inclined 9.5 degrees lingually, intruded two mm at the apex, and good anterior occlusion was achieved. Acceptable occlusion and periodontal tissue were maintained after a retention period of two years. Our results suggest that skeletal anchorage is useful for retraction and intrusion of upper incisors in cases of maxillary protrusion with severe adult periodontitis.     

Extreme skeletal open bite correction with vertical elastics

Severe skeletal open bites may be ideally treated with a combined surgical–orthodontic approach. Alternatively, compensations may be planned to camouflage the malocclusion with orthodontics alone. This case report describes the treatment of an 18-year-old man who presented with a severe open bite involving the anterior and posterior teeth up to the first molars, increased vertical dimension, bilateral Class III molar relationship, bilateral posterior crossbite, dental midline deviation, and absence of the maxillary right canine and the mandibular left first premolar. A treatment plan including the extraction of the mandibular right first premolar and based on uprighting and vertical control of the posterior teeth, combined with extrusion of the anterior teeth using multiloop edgewise archwire mechanics and elastics was chosen. After 6 months of alignment and 2 months of multiloop edgewise archwire mechanics, the open bite was significantly reduced. After 24 months of treatment, anterior teeth extrusion, posterior teeth intrusion, and counterclockwise mandibular rotation were accomplished. Satisfactory improvement of the overbite, overjet, sagittal malocclusion, and facial appearance were achieved. The mechanics used in this clinical case demonstrated good and stable results for open-bite correction at the 2-year posttreatment follow-up.