Rotated Incisors Research Articles

Enhanced conservation of vital pulp and apical tissues by the application of crown rotation surgery for inversely impacted central incisors: A follow‐up analysis of two patients over 4 years

To describe a novel surgical method (crown rotation surgery) to manage inversely impacted central incisors with immature roots. Two young patients each presented with an inversely impacted maxillary central incisor. To protect the apical tissues, the two impacted incisors were rotated downwards to a relatively normal position without extraction from their bony sockets. After crown rotation surgery, spontaneous eruption, continuous root development, and periodontal healing of the rotated incisors were observed. The pulp retained vitality and blood flow was normal. Moreover, there were no obvious signs of pulp canal obliteration (PCO), as indicated by Cone Beam Computed Tomography (CBCT) imaging. • By optimising protection of the vital pulp and apical tissues, crown rotation surgery represents a minimally invasive, conservative, and practical surgical technique for treating inversely impacted incisors with developing roots. • In contrast to existing surgical methods, crown rotation surgery may avoid certain complications, including PCO and abnormal or arrested root development.

The lingual versus labial biomechanics – A case report

Lingual orthodontics have stormed the world of orthodontics over the past few years with its esthetic superiority. But apart from its invisibility, this technique has very significant superiority in non extraction line of treatment where space is a requirement. This article is aimed at describing a case report of a 12-year-old girl who with almost 180 degree rotated upper left central incisor with its palatal surface facing labially. With the lingual technique the derotation of rotated incisor was completed. The incisors maintained the axial inclination without disturbing the profile. This proves that apart from the esthetic superiority, the lingual technique has the greatest advantage of its biomechanics in preventing unwanted proclination of anteriors, thus serving as the ultimate choice of treatment in non- extraction treatment.

Effectiveness of Er:YAG laser-aided fiberotomy and low-level laser therapy in alleviating relapse of rotated incisors

In this study, we compared the effectiveness of laser-aided circumferential supracrestal fiberotomy (CSF) and low-level laser therapy (LLLT) with conventional CSF in reducing relapse of corrected rotations. The study included 24 patients who were at the finishing stage of orthodontic treatment and had at least 1 maxillary incisor with 30° to 70° of rotation before starting therapy. The subjects were divided into 4 groups by treatment: conventional CSF, Er:YAG laser-aided CSF, LLLT, and control. After alginate impressions were taken, the archwire was sectioned from the experimental incisors, and they were allowed to relapse. The second impression was taken 1month later, and the degree and percentage of relapse were calculated in photographs taken from the dental models. Gingival recession, pocket depth, and pain were also measured in the CSF groups. The mean percentages of relapse were 9.7% in the conventional CSF, 12.7% in the Er:YAG laser-aided CSF, 11.7% in the LLLT, and 27.8% in the control groups. Relapse was significantly greater in the control than the experimental groups (P<0.05), which were not statistically different from each other. The changes in sulcus depth and gingival recession were small and not significantly different among the CSF groups (P>0.05), but pain intensity was greater in subjects who underwent conventional CSF (P=0.003). Er:YAG laser-aided CSF proved to be an effective alternative to conventional CSF in reducing rotational relapse. LLLT with excessively high energy density was also as effective as the CSF procedures in alleviating relapse, at least in the short term.

정중과잉치 조기 발거에 따른 상악 영구중절치 회전의 개선

과잉치는 정상치아의 수보다 증가되어 나타나는 치아로서 상악 중절치 사이의 과잉치를 정중과잉치라 부른다. 정중과잉치는 상악 전치의 맹출 장애를 포함하는 여러가지 병발증을 야기하지만 그 제거시기에 대해서는 아직 논란이 있다. 정중과잉치에 의해 발생하는 병발증을 피하기 위해 가능한 조기에 발견하여 제거해야 한다는 주장과 외과적 발거에 따른 인접 치아의 손상을 최소화하기위해 상악 영구 전치의 치근발육이 완성된 후 제거해야한다는 주장이 있다. 이에 저자는 정중과잉치로 인해 회전된 상악 중절치를 가진 세 명의 환자들에서 중절치가 치근발육 초기단계에 있을 때 정중과잉치를 제거함으로써 회전된 상악 영구중절치의 자연적인 개선이 보이는 바 이를 보고하고자 한다. Mesiodens is defined as a supernumerary tooth in the premaxillary region. It can cause several clinical manifestations in normal eruption and position of adjacent teeth, such as displacement and impaction. Although the mesiodens accompanied by a clinical complication is indicated for removal, the optimal time of mesiodens removal is still controversial. Some authors suggest immediate intervention defining the removal of mesiodens as soon as possible after the first detection. On the other hand, others recommend delayed intervention which denotes the removal of mesiodens after complete root development of adjacent teeth. This case report is presented with three cases of spontaneous correction and proper alignment of rotated maxillary central incisors by extraction of mesiodens when the crowns of rotated incisors were completely formed while the roots of them were at an early developmental stage.

A CAD-CAM prosthodontic option and gingival zenith position for a rotated maxillary right central incisor: An evaluation

Even with beautifully done restorations, an unattractive gingival zenith position, can negatively affect the smile of a person. In this short communication we describe the treatment of a rotated maxillary right central incisor using a digital photographic approach instead of the conventional approach. The conjecture literature on prosthodontic considerations and gingival zenith position in cases of rotated maxillary central incisors is sparse. The gingival zenith level (GZL) in an apical-coronal direction of lateral incisors, relative to the gingival tangential zenith line joining the adjacent central incisor and canine, is approximately 1 mm under healthy conditions. For our patient, the treatment plan was decided by CAD-CAM technique as Zirconia, jacket crown. Clinical procedures included enameloplasty on the left central and right lateral maxillary incisors. Reduction of the rotated and crooked incisor was performed in the normal manner; periodontal plastic surgery was also done. The patient expressed satisfaction with the intermediary (preliminary) two-dimensional photographs that were provided by the CAD-CAM system. The technique distinguished among the different treatment modalities for aesthetics and to relieve the emotional problems which were faced by female patient. The gingival zenith level of the rotated incisor was also improved. Digital imaging provides an immediate treatment option for the patients. Software also provides an interim aid, for the clinician as well as technician, in the form of two-dimensional photographs. CAD-CAM is entirely a helping instrument against the conservative prosthetic options and gingival zenith position for a rotated central incisor. It helps in patient education and in motivation.

Correction of anterior dental crossbite with composite as an inclined plane.

The purpose of this study was to evaluate a passive method to correct anterior crossbite of only one incisor by constructing a composite inclined plane. A total of 35 children aged 7-11 with a crossbite of only one incisor tooth were selected for this study. An inclined composite block 3-4 mm in size and 45 degrees to the longitudinal axis of the tooth, was constructed on the incisal edges of the related mandibular incisors. The occlusion was checked so that the only contact between both arches was at the level of these incisors. At the end of one week, 33 cases of crossbite were corrected by this method. Of the two cases which were not corrected one had a deep overbite and the second had a rotated incisor together with crossbite. The present results show that, a composite inclined plane is a useful technique to correct anterior crossbite of only one incisor tooth.

Position of Upper Permanent Central Incisors prior to Eruption in Unilateral Cleft Lip and Palate

The position and degree of eruption of permanent central incisors within the premaxilla were measured on x-ray films obtained in 102 patients with unilateral cleft lip and palate and in 52 normal individuals aged 5 years. The patients were subdivided according to sex and to the method of surgical repair (bone grafting or periosteal flap surgery). Individuals with rotated incisors were assessed separately. The results showed that maxillary depth was not significantly reduced prior to palate surgery while the alveolar process was markedly retroclined. An unerupted central upper incisor on the side of the cleft was situated more anteriorly than in controls. Because of the distortion of the alveolar process, it was retroclined and produced a deformation of the subspinal concavity. Both this deformation and the distortion of the alveolar process interfered with the measurements of maxillary depth and rendered it inadequate. The incisor on the normal side was situated more posteriorly than in controls and was less retroclined than the incisor on the affected side. The degree of eruption of incisors on both the normal and affected sides did not differ from controls. The type of surgical repair influenced only the retroclination of the alveolar process and of the incisors within this process. The retroclination was more marked after primary bone grafting than after periosteal flap surgery. The position and degree of eruption of rotated incisors did not differ from nonrotated incisors, and the presence of rotated incisors was not related to the degree of the shortening of maxillary depth. There were no significant differences between males and females.

Position of upper permanent central incisors prior to eruption in unilateral cleft lip and palate.

The position and degree of eruption of permanent central incisors within the premaxilla were measured on x-ray films obtained in 102 patients with unilateral cleft lip and palate and in 52 normal individuals aged 5 years. The patients were subdivided according to sex and to the method of surgical repair (bone grafting or periosteal flap surgery). Individuals with rotated incisors were assessed separately. The results showed that maxillary depth was not significantly reduced prior to palate surgery while the alveolar process was markedly retroclined. An unerupted central upper incisor on the side of the cleft was situated more anteriorly than in controls. Because of the distortion of the alveolar process, it was retroclined and produced a deformation of the subspinal concavity. Both this deformation and the distortion of the alveolar process interfered with the measurements of maxillary depth and rendered it inadequate. The incisor on the normal side was situated more posteriorly than in controls and was less retroclined than the incisor on the affected side. The degree of eruption of incisors on both the normal and affected sides did not differ from controls. The type of surgical repair influenced only the retroclination of the alveolar process and of the incisors within this process. The retroclination was more marked after primary bone grafting than after periosteal flap surgery. The position and degree of eruption of rotated incisors did not differ from nonrotated incisors, and the presence of rotated incisors was not related to the degree of the shortening of maxillary depth. There were no significant differences between males and females.

The effect of surgical transsection of free gingival fibers on the regression of orthodontically rotated teeth in the dog

The tendency for teeth to return to their original rotated positions following orthodontic alignment is a vexing problem for orthodontists. The purpose of this investigation was to assay the clinical adaptability of a minor surgical procedure as an adjunct to retention of orthodontically rotated teeth. The maxillary second incisors of five mongrel dogs approximately 1 year of age were rotated orthodontically. Appliance therapy for a period of 35 to 42 days resulted in rotations of 16 to 95 degrees. Following these rotations, the free gingival fibers were incised on the labial and lingual surfaces of the right second incisors. The left side served as a nonsurgical control. Subsequent to the surgical transsection of the free gingival fibers, the rotated incisors of four of the animals were retained for 148 to 150 days. Approximately 6 weeks following removal of the retentive appliances, the animals were killed by electrocution. The total period of repair was 190 to 192 days. For comparison, a fifth animal was retained for 14 days following the surgical procedure and was killed 4 weeks postretention, with a total repair period of 42 days. Study casts of tooth positions taken before treatment, before retention, and following retention revealed that the greatest percentage of regression occurred within the first 18 hours in the control incisors and was at a ratio of 24 to 1 as compared to the surgical side. The stability of the surgical side was evidenced by the fact that there was no regression in four of the animals and only 1 degree of regression in the fifth animal. Regression measured from the control incisors ranged from 5 to 34 degrees. Serial transverse sections of the maxilla were evaluated for the histologic changes. These changes were seen as cementum resorption, cementum repair, and areas of cementum deposition without prior resorption. To a lesser extent, osseous changes were evident. The alterations in cementum and bone were consistently more numerous and more extensive on the control side. Similarly, the degree of repair as evidenced by cementum and bone deposition was more complete on the surgical side. It may be theorized, on the basis of this finding, that the greater amount of tissue alteration on the control side was due to tooth movement during rerotation. The fibers in the cervical adnexa of the orthodontically rotated incisors were reorganized and demonstrated a fibrous pattern and density similar to that observed in the nonrotated first incisors. In the nonsurgical control incisors, regression of the rotations contributed to fiber reorganization, whereas on the surgical side, where regression was minimal, transsection of the fibers and subsequent repair resulted in fiber rearrangement. The surgical procedure resulted in reduction of the forces of regression transmitted by the displaced gingival tissues. Even more important, the repair of these fibers contributed to the retention of the rotated incisors. The stability of a rotated tooth is dependent upon many factors. However, analyses of the data from this investigation suggest that the transsection of the free gingival fibers following orthodontic tooth rotation, coupled with a period of retention allowing for optimum biologic repair, can be a definite adjunct to retention.