Measuring mesiodistal width of impacted maxillary canines

Aim

Precise, three-dimensional localization of impacted maxillary canines is central to their clinical management. Predicting precisely the crown??s mesiodistal width is paramount in planning orthodontic treatment. The aim of this study was to verify the exact mesiodistal width of impacted canines via MSCT (multislice spiral computed tomography) examinations.

Patients and methods

3D MSCT images from 17 patients with a total of 24 impacted maxillary canines were taken to obtain the largest mesiodistal diameter using mesial and distal contact points. All existing maxillary canines were included in this study. Mesiodistal tooth width was also determined using callipers on a plaster model after canine eruption. Each measurement was taken twice by 3 observers after a 10-day interval. Statistical analysis entailed calculating and comparing the systematic error, intrarater and interrater standard deviations (Deming regression and ANOVA with random effects).

Results

Comparison of the different methods revealed good agreement between the pre-eruption and post-eruption values regarding the canine??s mesiodistal width. Total standard deviation was 0.16?mm for values obtained from MSCT measurements and 0.12?mm for those taken with callipers. For both methods intrarater measurement error differed by a factor of 2 (repeatability; model versus MSCT: 0.07?mm versus 0.12?mm), while interrater deviation did not differ significantly (reproducibility; model versus MSCT: 0.10?mm versus 0.10?mm). The reproducibility of our measurements whether taken on the model or with CT was below biological variability.

Conclusions

The volumetric data from an MSCT system gives highly accurate information on the mesiodistal width of displaced canines.     

A retrospective study on the influence of maxillary canine impaction on premolar root morphology

Objectives

The root morphology of the maxillary first premolar differs from the other premolars by presenting a high incidence of separated roots. This study addressed the spatial conditions during root development as a possible influencing factor. Therefore, maxillary computed tomographic (CT) scans of patients with regularly erupted or impacted permanent canines were evaluated on the root morphology of the premolars.

Methods

The following parameters were retrospectively analysed in 250 maxillary CT scans (100 patients with regular erupted permanent canines, 150 patients with at least one impacted permanent canine): sex, status of the canines (erupted/impacted), position of the impacted canines (buccal/palatal; vertically inclined inside/outside the dental arch/horizontally inclined) and root morphology of the premolars.

Results

Of the patients, 68 % with at least one impacted canine were female; the canine was impacted palatally in 75.6 % and in a horizontally inclined position in 58.4 %. In patients with an impacted canine, the number of first and second premolars with separated roots was significantly reduced on the ipsilateral as well as on the contralateral side (all p values?<?0.01).

Conclusions

The present study detected an influence of maxillary canine impaction on the root morphology of all premolars, in that impaction and the associated surplus of space resulted in decreased root separation. This supports the hypothesis that root development is at least partly influenced by increased spatial conditions of the dental arch. However, root development can be regarded as a multifactorial event, influenced by space, direct mechanical interferences, as well as genetic predetermination. The retrospective nature of this observational study did not allow for conclusive differentiation between these factors. Alternatively, root separation and the mesial concavity of the first premolar may represent a path for canine eruption similar to the lateral incisor.

Clinical relevance

A single-rooted maxillary first premolar might represent an additional risk factor for canine impaction.     

Midline correction by asymmetric reciprocal torque: a pilot study

Objective

Can we correct dental midline discrepancies by systematic torque bends on all canines and premolars without extraction and mesiodistal tooth movement?

Patients and methods

Eight orthodontic patients (4?males, 4?females, mean age 31?years) presented a dental midline discrepancy of 2–4?mm, moderate deviation of the chin, no skeletal asymmetry, and a horizontal orientation of the occlusal plane in the frontal aspect. On the side where the mandible was shifted medially, asymmetric torque bends moved the antagonist canine and both premolar crowns buccally, while palatal crown torque was used on the maxillary canine and premolars on the other side. Lingual crown torque corrected the medially shifted canine and premolars in the mandibular dental arch, and buccal crown torque the laterally shifted lower canine and premolars.

Results

On average, torque effects altered the canine guidance by 6.5?±?4.7°, the first premolar guidance by 7?±?4.1°, and the second premolar guidance by 6.3?±?3.7°. Correction of the dental midline shift averaged 1.6?±?0.8?mm after the torque, and eliminated the midline discrepancy completely (n?=?2) or partly (n?=?6).

Conclusion

In this pilot study, asymmetric reciprocal torque represented a treatment option for midline corrections of approximately 2–4?mm and improvement in the chin position without mesiodistal tooth movement or extraction.     

Three-dimensional evaluation of angular,linear, and resorption features of maxillary impacted canines on cone-beam computed tomography

Objectives

The aim of this study was to evaluate the localization, angulation, and resorption features of maxillary impacted canines on cone-beam computed tomography (CBCT).

Methods

This retrospective study examined the CBCT scans of 140 maxillary impacted canines in 102 patients (43 males, 59 females; mean age: 16.25 ± 6.31 years). The following impacted canine-related parameters were analyzed on the CBCT images: impaction side; location; root resorption levels of adjacent teeth; occlusal plane and midline distances of impacted canines; and angulations of impacted canines to midline, lateral incisor, and occlusal plane.

Results

Bilateral canine impaction was found in 38 subjects, and unilateral canine impaction was present in 64 subjects. Severe resorption was found in 14 canines. There were no significant differences between the occlusal plane and midline distances to the impacted canine cusp tip and root apex (p > 0.05). The midline angulation of right maxillary impacted canines was significantly higher than that of left maxillary impacted canines (p < 0.05), while the occlusal plane angulation of left maxillary impacted canines was significantly higher than that of right maxillary impacted canines (p < 0.05).

Conclusions

Maxillary canine impaction was more frequently seen in female subjects than in male subjects. Lateral incisors were more frequently affected than first premolars, and slight resorption was more frequently seen in adjacent teeth. CBCT assessment of maxillary impacted canines can provide accurate measurements of angular, linear, and resorption parameters.

     

The prevalence of root resorption of maxillary incisors caused by impacted maxillary canines

Objectives

The aim of this study was to evaluate the prevalence of root resorption of maxillary incisors caused by impacted maxillary canines using low-dose dental computed tomography and to gain additional knowledge of the underlying aetiology and the progression of root resorption.

Materials and methods

A total of 440 patients (mean age, 24.7 years) with 557 impacted maxillary canines were examined regarding their location and the occurrence of root resorption of maxillary incisors.

Results

The frequency of root resorption was 2 % of central and 7.7 % of lateral maxillary incisors. The location of the 557 impacted canines within the dental arch was palatal in 67.5 %, buccal in 15.4 % and central in 17.1 %. No significant differences could be shown with respect to the width and the shape of the dental follicle of the impacted maxillary canines and the presence of root resorption of incisors. The presence of root resorption of central (p?<?0.0001) and lateral (p?<?0.023) maxillary incisors was significantly correlated with an existing contact relationship of the impacted maxillary canines.

Conclusions

Our investigation confirms the theory of prior reports comprising a much larger patient population, hypothesising that the dental follicle of impacted maxillary canines does not cause resorption of adjacent maxillary incisors per se.

Clinical relevance

Root resorption of maxillary incisors is correlated with effects of contact of the impacted maxillary canines, and these findings should be considered in treatment planning. Our findings are consistent with other reports and may develop new treatment approaches for the treatment of this sequela.     

Impacted upper canines: examination and treatment proposal based on 3D versus 2D diagnosis

Aim

The purpose of this diagnostic cross-over study was to evaluate whether three-dimensional (3D) diagnostics (cone-beam computed tomography, CBCT) was superior to two-dimensional (2D) diagnostics (panoramic X-ray, OPG) in patients with impacted upper canines for assessing their position and the probability of their alignment.

Materials and methods

Panoramic X-rays, CBCTs, and study casts of 21?patients with a total of 29 impacted maxillary canines were analyzed. Patients with syndromes or tooth aplasias were excluded. A total of 26?dentists of various specialist disciplines rated different parameters, such as canine position and their probability of alignment as well as their relation to and resorption of adjacent teeth. 2D X-rays and study casts were rated first; then 3D images and casts were evaluated at least 2?weeks later. The actual level of displacement was defined by two trained examiners and labeled as the master finding, according to modified criteria established by Ericson and Kurol (1988).

Results

In 64% of all patients, canine position was assessed concordantly in 2D and 3D images. 2D assessments were in slight agreement (???=?0.374), while 3D ratings were in good agreement with the master findings (???=?0.714). Two-thirds of the canines?? apical regions were judged identifiable in 2D and 3D images; more than 1/4 of the canines?? apices were not identifiable in 2D images, but were identifiable in 3D images. The diagnosis of lateral incisor root resorption in the CBCT agreed well with the master finding (???=?0.634), but examiners overlooked slight resorption in 20% of the patients. In 82% of the patients teeth, treatment suggestions (orthodontic alignment or surgical removal) were the same for 2D and 3D images. Canine inclination visible in the panoramic X-rays was the most important factor influencing the treatment proposal.

Conclusion

Small volume CBCT may be justified as a supplement to a routine panoramic X-ray in the following cases: when canine inclination in the panoramic X-ray exceeds 30°, when root resorption of adjacent teeth is suspected, and/or when the canine apex is not clearly discernible in the panoramic X-ray, implying dilaceration of the canine root. We intend to validate the results of this study in a clinical trial.     

Trattamento ortodontico-chirurgico di canini mascellari inclusi. Caso clinico

Objectives

Combined surgical-orthodontic treatment of impacted maxillary canines has advanced significantly in recent years, regarding management of both hard and soft tissues and forces of traction. The aim of this report is to describe a combined surgical-orthodontic approach used to treat an impacted maxillary canine and to evaluate the functional and esthetic results after 5 years of follow-up.

Materials and methods

A 13-year-old boy was seen in the Operative Unit of Orthodontics of Policlinico Tor Vergata in Rome. Radiographic images showed intraosseous impaction of tooth no. 2.3 in a setting of late mixed dentition, and the patient was scheduled for the combined surgical-orthodontic treatment.

Results

Five years after the combined treatment, the patient presented good occlusal stability.The maxillary canine that had been orthodontically repositioned showed keratinized mucosa of adequate width on the facial side with a margin that followed the course of the enamel-cement junction. Bleeding was absent on probing, the periodontal pocket depth was <4 mm, and there was no radiographically evident bone loss.

Conclusions

The combined surgical-orthodontic technique used in this case (closed eruption towards the center of the alveolar ridge associated with conservative periodontal surgery, the acid-etch technique, and controlled orthodontic traction) simulates physiological tooth eruption and results in proper alignment with good periodontal results. It should thus be regarded as the treatment of choice for impacted teeth whose eruption is not precluded by the position of the tooth and/or the presence of ankylosis.     

Extraction of Permanent Maxillary Teeth by Only Buccal Infiltration of Articaine

Objective

The aim of this study is to demonstrate whether articaine hydrochloride administered alone as a single buccal infiltration in maxillary tooth removal, can provide favourable palatal anesthesia as compared to buccal and palatal injection of lidocaine.

Study Design

The study population consisted of 30 patients who were undergoing orthodontic treatment, and who required bilateral extraction of maxillary permanent premolars as per their orthodontic treatment plan. On the experimental side, 4 % articaine/HCl was injected into the buccal vestibule of the tooth to be extracted. On the control side, 2 % lignocaine HCl was injected both into the buccal and the palatal side of the tooth to be extracted. Following tooth extraction all patients completed a 100-mm visual analogue scale (VAS) and faces pain scale (FPS) to rate the pain on extraction.

Results

According to the VAS and FPS scores, the pain on extraction between buccal infiltration of articaine and the routine buccal and palatal infiltration of lignocaine was statistically insignificant.

Conclusions

The routine use of a palatal injection for the removal of permanent maxillary premolar teeth may not be required when articaine/HCl is used as the local anesthetic.     

Mass retraction movement of the anterior upper teeth using orthodontic mini-implants as anchorage

Background

Several studies have demonstrated the application of mini-implants in the orthodontic treatment as anchorage during the retraction movement of the anterior teeth.

Purpose

This study was designed to evaluate the mass retraction movement of the anterior upper teeth using orthodontic mini-implants as anchorage.

Materials and methods

Nine patients with class I malocclusion and Angle's class II, needing extractions of the upper first premolars, were enrolled in this case series. The retraction was performed using sliding mechanics and orthodontic anchorage on mini-implants. Measures were taken by initial and final cephalometric X-rays of the retraction movement to evaluate whether the mini-implants remained stationary and displacements of the incisors and the upper first premolars.

Results

Out of 18 mini-implants, 8 mesialized (0.45?mm, average) and 3 extruded (0.14?mm, average). The upper incisors were retracted on the average of 4.21?mm, extruded 0.33?mm, and tipped 10.3°. There were no statistical significant modifications in the placement of the posterior teeth.

Conclusions

Although there was a very small displacement of the mini-implants, they still provided an adequate anchorage for the retraction of the anterior teeth, and there was no loss in the anchorage of the posterior teeth.     

Orthodontic management of a dilacerated central incisor and partially impacted canine with unilateral extraction – A case report

Aim

To align a dilacerated maxillary central incisor and partially impacted canine with unilateral extraction in a young patient with skeletal deep bite.

Management of over retention of permanent incisor impacted by compound odontoma: Clinical,radiological, and microscopic evaluation

Objective

This case report describes the management of primary tooth over retention and permanent impacted tooth a compound odontoma and the microscopic evaluation.

Maxillary impacted canine with congenitally absent premolars

Multiple treatment options are available to patients who have impacted canines in addition to congenitally absent premolars. Management options for impacted maxillary canines can include (1) continued observation, (2) extraction of the primary canine to aid spontaneous eruption, (3) uncovering and bonding of the impacted tooth and its eruption using orthodontic traction, (4) autotransplantation, and (5) extraction followed by prosthetic replacement. The options for the treatment of missing premolars can include the following: (1) maintaining the primary molars, (2) spontaneous space closure after early extraction of the primary molar, (3) autotransplantation, (4) prosthetic replacement, and (5) orthodontic space closure. In this case report, treatment of a patient with an impacted maxillary canine and agenesis of three second premolars will be presented.     

The topography of displaced canines

Aim

This study investigated the development of a three-dimensional (3D) coordinate system for radiologic volumetric data, allowing the analysis of the tooth axis of displaced teeth in relation to the occlusal, frontal, and sagittal reference planes.

Patients and methods

The data basis consisted of multislice computed tomography (MSCT) data of 37?patients with displaced upper canines. A total of 20?patients displayed unilateral displacement and 17?patients bilateral displacement (n?=?54). The non-displaced canines of the opposite side served as the reference group (n?=?20), together with MSCT data of 6?patients with non-displaced canines (n?=?12). Three reference planes were constructed in the VoXim?5.6 program using landmarks (apex point and tip of the canine, incision point of the lower jaw, mesiobuccal tip of the lower left and right first molar, A-point). The tooth axis of the canines was analyzed in relation to these planes.

Results

The angle to the frontal plane was only slightly smaller in non-displaced canines (mean: 17.53°) than in palatally displaced canines (mean: 19.62°), which however exhibited a considerably greater range (0.40?C38.00°). In contrast, the mean angle in buccally displaced canines was 32.79°. Both the differences between the reference group and buccally displaced canines and those between the palatally and buccally displaced canines were statistically significant. The angles for buccal (55.16°) and palatal (56.63°) displacement relative to the occlusal plane were significantly smaller than for the non-displaced teeth (70.95°). However, the range of palatal displacement was high (27.3?C80.6°). The inclination towards the sagittal plane was slight for non-displaced canines (mean 6.07°) and for buccally displaced canines (mean 8.25°). The mean angle of palatally displaced canines was significantly larger (23.28°) than that in the other groups, with a much greater range (6.70?C50.80°).

Conclusion

The 3D coordinate system developed in this study allows the exact measurement of tooth position relative to three spatial planes, thus, enabling tooth position to be objectively determined.     

Traction of an impacted maxillary canine with corticotomy in a 53-year-old patient: Case report

The viability of orthodontic traction of impacted teeth in adults is often questioned by a large percentage of orthodontists who would rather consider the extraction of these teeth. Although possible, orthodontic traction of impacted canines in adults takes longer than in younger patients, present a poorer prognosis that worsens with age. Because of the prevalence of periodontitis in adults versus children, periodontal inflammation must be identified and resolved in order to keep attachment loss from progressing during orthodontic care. Likewise mucogingival changes need to be predicted and managed. This article reports a successful case of impacted maxillary right canine traction in an adult female, associated with alveolar corticotomies and the use of skeletal anchorage. At the end of treatment, the canine was ideally positioned in the occlusion, presenting excellent esthetics, function, and healthy periodontal tissues.     

Impact of extracorporeal shock wave therapy (ESWT) on orthodontic tooth movement—a randomized clinical trial

Objectives

This randomized clinical trial investigated the effect of extracorporeal shock waves on the amount of orthodontic tooth movement and periodontal parameters.

Material and methods

Twenty-six adult orthodontic patients participated in this clinical trial; all of them receiving lower second molar mesially directed movement. The fixed orthodontic device included superelastic coil springs (200 cN) and miniscrews as temporary anchorage device. The active treatment group received a single shock wave treatment with 1,000 impulses in the region of tooth movement. The placebo group was treated with deactivated shock wave applicator with an acoustic sham. The study period lasted 4 months with a monthly data exploration.

Results

No statistically significant difference in posterior-anterior tooth movement between the treatment and placebo group was seen during observation period. Gender had no significant influence on tooth movement in either group. No significant difference occurred in mesio-distal tipping and rotation, but a significant difference (p?=?0.035) in bucco-lingual tipping of the molars was found. Periodontal status of the patients (sulcus probing depth, gingival index) did not significantly differ in both groups. The plaque index showed a significant difference (p?=?0.003).

Conclusions

Single application of extracorporeal shock wave treatment was associated neither with a statistically significant acceleration of tooth movement nor with an altered periodontal status in vivo.

Clinical relevance

Shock waves showed no harmful effects in the investigated area. Their clinical use for lithotripsy during orthodontic therapy might be permitted.     

A Comparative Study of Canine Retraction by Distraction of the Periodontal Ligament and Dentoalveolar Distraction Methods

Introduction

Canine distraction was introduced as an alternative treatment to retract the canines in minimum possible period of 3 weeks. It involved rapid canine retraction through distraction of the periodontal ligament. Another technique for rapid canine distalization involved osteotomies surrounding the canines to achieve rapid movement of the canines in the dentoalveolar segment known as dentoalveolar distraction. The present study is intended to assess and evaluate canine retraction by the above two mentioned methods of distraction osteogenesis.

Materials and Methods

Eight orthodontic patients who required first premolar extractions were selected and 16 canines were distracted into the extraction space, using a distraction screw.

Results

The distraction procedure was completed in 15.38 ± 1.51 days on the side of periodontal ligament distraction while it took 14.50 ± 2.45 days on the side of dentoalveolar distraction. No significant anchorage loss was seen in both the sides. The distal displacement of the canines was 6.63 ± 0.90 mm on the periodontal distraction side at the rate of 0.43 ± 0.05 mm/day and 6.91 ± 1.16 mm on the side of dentoalveolar distraction at the rate of 0.48 ± 0.08 mm/day. An angulation change of 14.94° ± 7.58° was observed in canine inclination in periodontal distraction side while change of 14.88° ± 3.15° was seen in the dentoalveolar distraction side.

Conclusion

No significant differences in the various parameters were found between both the techniques of canine retraction by distraction osteogenesis, while reducing orthodontic treatment duration by 6–9 months without any unfavorable short-term effects on the periodontium.

     

改良Nance弓在矫治上颌腭侧埋伏尖牙的作用

目的 探讨改良Nance弓在矫治上颌腭侧埋伏尖牙时矫治力方向设计及支抗设计的作用.方法 7例单侧上颌腭侧埋伏尖牙均采用外科-正畸联合治疗.手术暴露埋伏尖牙牙冠,粘接舌侧扣;戴入改良Nance弓,利用改良Nance弓位于腭侧不锈钢丝上的附钩,先将尖牙冠向后牵引绕过侧切牙的牙根,直到位于正常尖牙间隙的腭侧,如尖牙间隙不足,则粘结上颌托槽,预备尖牙间隙;再采用直丝弓技术将埋伏尖牙向唇侧移动,排齐牙列,调整咬合关系.对治疗后牙齿的松动度、牙髓活力等进行观察.结果 7位埋伏尖牙均被牵引至牙弓的正常位置;牙髓活力测试正常,牙周附着良好.结论 改良Nance弓在矫治上颌腭侧埋伏尖牙时,在矫治力方向设计和支抗控制方面有独特优点和作用.     

上颌尖牙埋伏阻生的外科-正畸联合治疗

目的:探讨尖牙埋伏阻生的外科-正畸联合治疗方法。方法:20例患者28颗上颌埋伏阻生尖牙,先用滑动直丝弓矫治器初步排齐牙列后,再局部间隙扩展,采用外科闭合式助萌技术,暴露埋伏尖牙牙冠,粘贴托槽,再进行正畸牵引导萌。结果:24颗埋伏尖牙均牵引入正常牙列,牙髓、牙周情况正常。有4颗尖牙因横位阻生和根冠成角采用外科拔除。结论:通过外科手术暴露和正畸牵引导萌联合治疗,能有效矫治埋伏阻生尖牙。     

Traumatic displacement of maxillary permanent incisor into the nasal cavity

Purpose

The purpose of this paper was to describe a case of unviable alveolar repositioning of an intruded tooth into the nasal cavity and to bring the subject of intrusive tooth injury among patients with dentoalveolar fractures to the attention of trauma surgeons.

Patient

A 26-year-old male was involved in a car accident and crashed his mouth against the dashboard due to sudden deceleration. Intraoral examination revealed an anterior maxillary dentoalveolar fracture and absence of the central maxillary incisors, right lateral maxillary incisor, and left maxillary canine. Computed tomography showed a dislocated tooth in the nasal cavity. The “missing” left maxillary canine was easily recovered from the floor of the left nostril.

Conclusions

Because complete dislocation of a tooth can cause a frontal sinus abscess, an airway complication, a respiratory tract obstruction, and a complicated lung abscess or sinusitis, anytime a tooth is not accounted for after a dentoalveolar trauma, the possibility that it has been fully intruded should be considered. Computed tomographic scan should be a routine diagnostic study in all cases with associated missing anatomical structures in the oral and maxillofacial region. The need to involve the dental professional in the initial assessment of dental trauma in emergency rooms in hospitals is important in order to identify how many teeth might be missing after dental trauma and to correctly reposition the avulsed teeth when possible.     

上颌阻生尖牙牵引治疗后邻近切牙牙根吸收情况的研究

目的 分析上颌阻生尖牙正畸牵引治疗后邻近切牙的牙根吸收情况及可能的相关因素。方法 选取上颌尖牙阻生且符合标准的43例患者,年龄10～23岁,共60颗上颌埋伏阻生尖牙。上颌阻生尖牙正畸牵引治疗前后分别拍摄锥形束CT,分析阻生尖牙邻近切牙的牙根吸收程度,并对可能存在的相关因素进行分析。结果 上颌阻生尖牙正畸牵引治疗后,上颌中切牙发生轻、中、重度牙根吸收的概率分别为71.7%、15.0%、13.3%,上颌侧切牙发生轻、中、重度牙根吸收的概率分别为48.3%、36.7%、15.0%,上颌中切牙与侧切牙牙根吸收严重程度存在差异(P<0.05)。位于腭侧及颌骨内、低位且靠近面中线的阻生尖牙,在正畸牵引治疗后,侧切牙牙根吸收程度较重(P<0.05)。低位阻生尖牙牵引治疗后,中切牙牙根吸收较重(P<0.05)。牵引时间较长时,中切牙牙根吸收程度较重(P<0.05)。治疗前已发生牙根吸收的切牙,在阻生尖牙牵引治疗后发生的牙根吸收程度较重(P<0.05)。结论 上颌侧切牙在阻生尖牙正畸牵引治疗后,发生的牙根吸收程度较重。上颌阻生尖牙正畸牵引治疗后,邻近切牙牙根吸收情况与阻生尖...