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.

     

Orthodontic screws to extrude impacted maxillary canines

Objective

The impaction of maxillary canines is a frequently encountered clinical problem in orthodontic practice. Patients?? refusal to participate in long-term treatment or ankylosis of the impacted tooth result in various treatment difficulties. The aim of this study was to evaluate the possible role of mini-screws in the management of unerupted upper canines.

Patients and methods

In a series of 63 consecutive patients (27 males and 36 females, age range 14?C49?years, mean 22.7?years) with a total of 69 impacted maxillary canines, each impacted tooth was surgically exposed and an attachment bonded. An intraosseous screw with an endosseous body and intraoral neck section was inserted into the premolar?Cmolar interradicular space. Following soft tissue healing, orthodontic traction was initiated. After correction of the canine angulation, the mini-screw was removed and conventional orthodontic therapy completed.

Results

Of the 69?canines, 61 (88.41%) were extruded successfully. In the 7?cases that failed, skeletal anchorage spared both patients and clinicians the disappointment of customary long-term, unsuccessful orthodontic therapy. In one patient, the mini-screw was removed because of inflammation and pain before initiating orthodontic traction.

Conclusion

Our results demonstrate that mini-screw anchorage should be taken into consideration when extrusion of an impacted canine is planned.     

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.     

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.     

Inclusione dei canini mascellari permanenti e riassorbimento radicolare degli incisivi: prevenzione e aspetti medico-legali

Objectives

To discuss the risk of incisor root resorption in the presence of ectopic eruption of the permanent maxillary canines.

Discussion

Early detection of an anomalous intraosseous position of the maxillary canine is essential. To this end, patients should undergo a comprehensive clinical and radiographic assessment starting at the age 8 years.

Results and conclusions

Eruption of the ectopic permanent canines can be facilitated with early extraction of the primary maxillary canines (and possibly the primary first molars). This approach can prevent impaction (which requires more complicated, prolonged, and biologically expensive treatment) and limit the risk of root resorption involving the adjacent teeth (an event that causes irreversible damage and may give rise to medicolegal litigation).     

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.     

Prediction of maxillary canine impaction using eruption pathway and angular measurement on panoramic radiographs

ObjectivesTo compare the normal eruption pattern and angulation in impacted maxillary canines using panoramic radiographs to predict maxillary canine impaction.Materials and MethodsPatients aged 6 to 15 years were classified into the normal eruption group (n = 229) and the impaction group (n = 191). At least two panoramic radiographs were taken in the normal eruption group during the eruption process of the maxillary canine. The growth pattern of the maxillary canine was analyzed using an XY coordinate system, with the tip of the maxillary lateral incisor as the origin and the tooth''s long axis as the Y-axis and measurement of the relative position of the crown tip and angulation of the maxillary canine.ResultsThe crown tips of normally erupted maxillary canines were intensively distributed along the distal surface of the maxillary lateral incisor, while those of impacted canines were widely distributed. The angulations of the normally erupted canines increased as eruption increased along the lateral incisor and then decreased at the cervical point of the lateral incisor. The angulations of the impacted canines were scattered, with no uniform pattern.ConclusionsWhile using the normal eruption path of the maxillary canine and the pattern of change in angulation based on the distal surface of the maxillary lateral incisor, early intervention or regular follow-up is needed to prevent maxillary canine impaction.     

Cementoblastoma: A case report in deciduous tooth

Background

The benign cementoblastoma is an odontogenic tumor originated from neoplastic cementoblasts, a rare lesion mainly associated to impacted and deciduous teeth. It affects mostly young people with an average age of 20 years old, and its preferred location is in the posterior region of the mandible; the lesion will present itself fused both radiologically and microscopically to a root of an erupted permanent tooth, and the anatomopathological diagnosis is obtained through the analysis of the piece sent together with the involved dental element.

Case report

The present study presents a case of cementoblastoma in the mandible involving the second deciduous molar tooth and preventing the eruption of the premolar tooth in a girl aged 11 years old.

Discussion

This report discusses relevant aspects concerning clinical, radiographic, and histopathological characteristics and treatments.     

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.

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.     

阻生前磨牙的临床研究现状

阻生牙是口腔中较常见的一种发育畸形,以尖牙、第三磨牙、中切牙、前磨牙及第二磨牙的阻生多见,尤以下颌第三磨牙及上颌尖牙阻生的患病率最高。目前国内外学者对阻生牙的研究主要集中在上颌尖牙和第三磨牙方面,对阻生前磨牙的研究甚少。临床上,很大一部分正畸患者需要进行拔牙矫治,且拔牙牙位主要位于前磨牙区,可见阻生前磨牙对正畸矫治设计及预后影响极大。本文对阻生前磨牙现有的研究状况进行综述,对阻生前磨牙的流行病学特点、临床定位和治疗方法进行总结,以期为正畸医生制定正畸矫治计划提供参考。     

单侧上颌尖牙阻生对牙颌三维结构的影响

目的: 采用锥形束CT（CBCT）研究单侧尖牙阻生病例牙颌的三维结构特征,评估发生上颌尖牙阻生的相关风险因素,为正畸临床早期干预提供依据。方法: 选取30例单侧上颌尖牙阻生患者的CBCT,利用Romexis软件进行三维重建,测量、比较两侧牙颌三维结构特征指标,采用SPSS17.0软件包进行配对t检验和相关数据的回归分析。结果: 阻生侧尖牙和侧切牙倾斜度明显增大,尖牙牙冠更向近中、侧切牙向远中倾斜（P<0.001）;阻生侧尖牙体积更大、侧切牙体积更小（P<0.05）,当尖牙体积增大或侧切牙体积减小时,上颌尖牙的阻生概率增加;阻生侧牙弓弧形长度更短,牙弓宽度在尖牙区和前磨牙区更短（P<0.001）,而宽度在磨牙区无显著差异（P>0.05）,两侧牙弓长度在尖牙区、前磨牙区和磨牙区无显著差异（P>0.05）。结论: 上颌尖牙阻生伴随或导致同侧牙及牙槽骨三维方向发育异常,上颌尖牙阻生的严重程度与周围牙颌结构异常密切相关,提示上颌尖牙阻生可以早期预判、诊断,且可以实施有效的早期干预。     

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.     

Clinical conditions for eruption of maxillary canines and mandibular premolars associated with dentigerous cysts.

The aim of this study was to investigate the eruption of teeth associated with dentigerous cysts in the mandibular premolar and maxillary canine regions in preadolescents. Fifty-eight cyst-associated teeth, including 47 mandibular premolars and 11 maxillary canines, were examined retrospectively by using normalized panoramic radiographs and histological materials. The subjects were divided into 2 groups: the erupted group, in which the teeth had erupted successfully after marsupialization, and the nonerupted group, in which the teeth had undergone orthodontic traction or cystectomy with removal of the cyst-associated tooth. Eighty-one percent of the mandibular premolars and 36% of the maxillary canines in the cysts erupted successfully about 100 days after marsupialization without traction. The eruption of a mandibular premolar was significantly related to a shallow position in the alveolar bone, shallow angulation of the tooth, and young age of the patient but not to cyst size and dental space for the eruption. The eruption of the maxillary canine was significantly related to the small size of the cyst and the patient's age. The cyst walls of the erupted group showed severe inflammatory cellular infiltration. These findings present a treatment guideline for dentigerous cysts associated with mandibular premolars and maxillary canines in preadolescents.     

Three-rooted premolar analyzed by high-resolution and cone beam CT

Objectives

The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (μCT) and cone beam computed tomography (CBCT).

Materials and methods

Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using μCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using μCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals.

Results

Images using μCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the μCT and CBCT techniques (P?<?0.05). Root and canal areas had similar variations in cross-sectional μCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically.

Conclusion

Although variation was similar in the roots and canals under study, CBCT produced poorer image details than μCT.

Clinical relevance

Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.     

A micro-computed tomography study of the root canal morphology of the mandibular first premolar in a population from southwestern China

Objectives

This study aimed to investigate the root canal morphology of mandibular first premolar teeth in a population from southwestern China by micro-computed tomography (micro-CT).

Materials and methods

Human mandibular first premolars (115) were selected and prepared for micro-CT analysis with a slice thickness of 30 μm. Details of root canal orifices, canals, accessory canals, apical foramina–apical delta intercanal communication, loops and isthmuses, and mesial invagination were analyzed from reconstructed three-dimensional (3D) images.

Results

Canal patterns categorized according to the classification defined by Vertucci (Endod Top 10:3–29, 2005) as types I (65.2 %), III (2.6 %), V (22.6 %), and VII were identified (0.9 %). Accessory canals were present in 35.7 % of the samples and were predominantly located in the apical third of the root. A single apical foramen was observed in 50.4 % of the samples and two or three foramina in 28.7 % and 14.8 %, respectively. Apical delta was identified in 6.1 % of the samples and the prevalence of intercanal communication and loops was 3.5 % and 7 %, respectively. Mesial invagination of the root was identified in 27.8 % of the samples, the majority of which contained multiple canals.

Conclusions

The data obtained in this study revealed complex root morphology with high prevalence of multiple canals, more than half of which exhibited type I canal patterns.

Clinical relevance

Micro-CT was used as a noninvasive technique for 3D investigation of root canal morphology in the mandibular first premolars of a population from southwestern China. Furthermore, data obtained revealed complex anatomy of various types.     

泸州地区青少年尖牙阻生的X线分析

目的：通过X线全景片分析泸州地区青少年的尖牙阻生情况。方法：选取2011年1月。2012年12月在泸州医学院附属口腔医院接受x线检查的1800例12—14岁青少年的X线全景片,统计分析阻生尖牙所占比例以及患者的性别、尖牙阻生部位和阻生类型的差异。结果：尖牙阻生在所有患者中所占比例为3．72％（67／1800）,男性：女性为1：1．79;上颌尖牙阻生占3．33％（60／1800）,下颌尖牙阻生占0．33％（6／1800）,上下颌尖牙同时阻生1例;近中向阻生在阻生尖牙中占92％（69／75）,迁徙尖牙占0．22％（4／1800）。结论：本组患者尖牙阻生以女性、单侧上颌尖牙阻生多见,且以近中向阻生为主。     

Maxillary sinus volume in patients with impacted canines

Objectives:To evaluate the maxillary sinus volumes in unilaterally impacted canine patients and to compare the volumetric changes that occur after the eruption of canines to the dental arch using cone beam computed tomography (CBCT).Materials and Methods:Pre- (T0) and posttreatment (T1) CBCT records of 30 patients were used to calculate maxillary sinus volumes between the impacted and erupted canine sides. The InVivoDental 5.0 program was used to measure the volume of the maxillary sinuses. The distance from impacted canine cusp tip to the target point on the palatal plane was also measured.Results:Right maxillary sinus volume was statistically significantly smaller compared to that of the left maxillary sinus when the canine was impacted on the right side at T0. According to the T1 measurements there was no significant difference between the mean volumes of the impaction side and the contralateral side. The distance from the canine tip to its target point on the palatal plane were 17.17 mm, and the distance from the tip to the target point was 15.14 mm for the left- and right-side impacted canines, respectively, and there was a significant difference between the mean amount of change of both sides of maxillary sinuses after treatment of impacted canines.Conclusions:Orthodontic treatment of impacted canines created a significant increase in maxillary sinus volume when the impacted canines were closer with respect to the maxillary sinus.     

To what extent are impacted canines associated with root resorption of the adjacent tooth?: A systematic review with meta-analysis

Background

The authors’ aim in this systematic review was to evaluate to what extent impacted canines are associated with root resorption (RR) of the adjacent tooth by using cone-beam computed tomography.