Treatment of an ankylosed central incisor by single tooth dento-osseous osteotomy and a simple distraction device.

When teeth are replanted after being avulsed, the repair process sometimes results in ankylosis. In a growing child, the ankylosed tooth fails to move along with the remaining alveolar process during vertical growth, resulting in a tooth that gradually appears more and more impacted and requires several reconstructive procedures to correct. Ankylosed teeth can, however, serve as anchorage for orthodontic correction of a malocclusion and as a point of force application for a dentoalveolar segment during alveolar distraction osteogenesis. This case report describes the treatment of a 13-year-old girl whose maxillary left central incisor had been avulsed and replanted 5 years earlier. The tooth had become ankylosed, and it was used to provide "free anchorage" during distalization of the maxillary dentition. The underdeveloped alveolar process adjacent to the ankylosed tooth was reconstructed by dento-osseous segment distraction osteogenesis, by using the ankylosed tooth as the point of force application.     

Management of impacted canines.

In this article an overview of the problem of impacted canines has been presented and some of the clinical considerations related to surgical management and types of attachments have been discussed. In the orthodontic management of impacted canines the clinician has to make certain decisions regarding one-arch vs. two-arch treatment and canine vs. first premolar extraction. The factors which might influence such decisions were also discussed.     

Radiographic factors affecting the management of impacted upper permanent canines

The aim of the investigation was to evaluate which radiographic factors influenced the orthodontists' decision whether to expose or remove an impacted upper permanent canine and was a retrospective, cross-sectional design. The sample consisted of all radiographic records of patients referred to the Orthodontic Department at Manchester University Dental Hospital with impacted upper permanent canines between 1994-1998 (n = 44). The following canine position measurements were made from the OPG: angulation to the midline, vertical height, antero-posterior position of the root, overlap of the adjacent incisor, and presence of root resorption of adjacent incisor(s). The labio-palatal position of the impacted canine was assessed from the lateral skull radiograph. Whether the impacted canine had been exposed and orthodontically aligned or removed was also recorded. Stepwise logistic regression analysis showed that the labio-palatal position of the crown influenced the treatment decision, with palatally positioned impacted canines more likely to be surgically exposed and those in the line of the arch, or labially situated, removed (P < 0.05). Additionally, as the canine angulation to the midline increased, the canine was more likely to be removed (P < 0.05). The orthodontists' decision to expose or remove an impacted upper permanent canine, based on radiographic information, seems to be primarily guided by two factors: labio-palatal crown position and angulation to the midline.     

X-ray diagnosis of impacted upper canines in panoramic radiographs and computed tomographs

Ten orthodontists were asked to diagnose the number of impacted upper canines and the number of resorbed lateral and/or central incisor roots in 30 panoramic radiographs (P1) from 30 patients. In order to objectify these diagnoses, transversal CT images of all 30 patients were examined in addition. Addition of the recordings in the 30 patients revealed that the 10 orthodontists had diagnosed 350 impacted/displaced canines. On comparison of the P1 and CT results, the latter revealed that, in fact, 390 canines were impacted or displaced, not just 350. Addition of the recordings further showed that, based on P1, the investigators had diagnosed 73 resorptions in the 1,200 incisors examined. However, the CT showed 160 resorptions; this corresponds to a sensitivity value of 45.6%. The CT showed 1,040 incisors with no resorptions, whereas the investigators diagnosed only 925 teeth as not resorbed in the P1. The specificity was thus 88.9%. These results show that, due to their low reliability, panoramic radiographs are not an appropriate means of diagnosing resorptions in front teeth in connection with impacted canines.     

Treatment of ankylosed maxillary central incisors by single-tooth dento-osseous osteotomy and alveolar bone distraction

When tooth ankylosis occurs in growing children, the ankylosed tooth fails to erupt and gradually positions itself below the occlusal plane. This causes functional and esthetic problems, and orthodontic treatment is often impossible. To clarify this problem, we developed a new treatment protocol for the movement of ankylosed teeth. This consists of single-tooth dento-osseous osteotomy and alveolar bone distraction using orthodontic multibracket appliances. A special distraction device is not required, thus reducing the burden to patients. Two cases in which an ankylosed maxillary central incisor was successfully treated with this protocol are presented.     

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阻生牙是临床上常见的牙齿发育障碍之一,尖牙阻生是最常见的类型,其中腭侧阻生尖牙发生率较唇侧阻生更常见。如何准确地诊断、治疗腭侧阻生的尖牙,一直是正畸中非常有挑战的内容。借助锥形束CT的帮助,阻生尖牙的诊断变得越来越容易。激光的应用使开窗手术更易止血,粘接操作更准确可靠。灵活、有序的正畸牵引,使牵引过程更可控,从而提高了治疗效率。对牙周的关注,更加提高了阻生尖牙治疗后的质量。阻生牙牵引后更需注意保持,3～6个月的固定保持更有利于牙周的改建。     

Autogenous transplantation of impacted maxillary canines

The authors report on three patients who received four autogenous transplantations of impacted maxillary canines, relate the technique used, and discuss the advantages and disadvantages of this surgical procedure.     

Presurgical recovery of palatally impacted canines

A bstract — A procedure is described whereby certain palatally impacted canines can be induced to erupt into the dental arch by exerting pressure on the soft tissue overlying the crown or root or both. Criteria for the successful selection of cases are suggested.     

改良横腭杆作支抗协助导萌腭侧埋伏阻生尖牙10例报告

目的：探讨使用改良的横腭杆正畸临床矫治腭侧埋伏阻生尖牙的疗效。方法：选择2010～2012年在周口市口腔医院正畸科就诊的腭侧埋伏阻生尖牙10例,均经螺旋CT检查确诊为腭侧埋伏,并有较大把握导萌者。所有患者都采用了改良横腭杆的矫治方法。结果：经过平均7.6个月的导萌治疗（最短4.6个月,最长8.4个月）10个病例共12颗埋伏阻生尖牙均导萌成功,埋伏阻生的尖牙均移至理想的位置,咬合关系良好,牙龈附着满意,未见有牙根吸收现象。结论：改良横腭杆协助正畸临床导萌腭侧埋伏阻生尖牙是一种行之有效的治疗方法。     

Orthodontic treatment of palatally impacted maxillary canines

The aim of this study was to determine the feasibility of treating children with impacted maxillary canines by orthodontic treatment alone. The subjects were 28 children (mean age: 13.5 years, range 11.4-16.1 years) with between them 32 palatally impacted canines. The overlying primary canines were extracted between 0 and 42 months before the start of appliance treatment to open space in the arches for the impacted teeth. No other surgical procedures were carried out prior to the start of appliance treatment. Appliance treatment was deferred for at least six months if an impacted canine was the main reason for treatment, otherwise treatment was commenced according to the needs of the patient. In 94% of the cases, the severity of impaction lessened following extraction of the overlying primary canines and orthodontic treatment. The deepest impactions tended to occur in the oldest children. The majority (75%) of the canines emerged following orthodontic treatment to create space for them in the arch; the remainder were surgically exposed. Appliance treatment tended to take longer in children with the deepest impactions. It is concluded that fixed appliance treatment to create space for a palatally impacted canine is an effective management option for children with impacted maxillary canines.