The labiopalatal impacted canine: Accurate diagnosis based on the position and size of adjacent teeth: A cone-beam computed tomography study.

INTRODUCTION: Labiopalatal impacted canines (L-PICs) occur when the canines lie between central and lateral incisors, with their tip palatal to the central incisor and part of their crown labial to the lateral incisor. Because of their unusual position, they are often misdiagnosed, and their orthodontic resolution fails. This study aims to provide clinicians with pathognomonic features for early and accurate positional diagnosis of L-PICs. METHODS: The L-PIC sample included 21 subjects with full diagnostic records. The control group of normally erupted canines was taken from a previous study. Clinical photographs, 2-dimensional radiographs, and cone-beam computed tomography were used to evaluate the positions of the adjacent incisors and first premolars, the canine incisor index, and the mesiodistal width of the lateral vs central incisors. RESULTS: Central incisors adjacent to L-PICs showed significant mesial root angulation, labial root inclination, and mesiolabial crown rotation, whereas lateral incisors presented significant distal root angulation, palatal root inclination, and mesiolabial crown rotation, in comparison to controls. The roots of the central and lateral incisors were divergent, in contrast to the controls, in which they were slightly convergent. The first premolar positions were not affected. The mean canine incisor index was significantly bigger in L-PICs vs the controls, suggesting a palatal canine. The lateral incisor widths were similar between the groups. CONCLUSIONS: This study provides the orthodontist with evidence-based clinical and radiographic red flags for diagnosing L-PIC, which may allow timely initiation of orthodontic treatment and correct planning of mechanotherapy.

Impaction of maxillary canines and its effect on the position of adjacent teeth and canine development: A cone-beam computed tomography study.

INTRODUCTION: The purposes of this study were to characterize the 3-dimensional position of teeth adjacent to impacted canines and examine whether impaction affects canine development using cone-beam computed tomography. METHODS: Cone-beam computed tomography images of 34 unilateral maxillary impacted canines (12 males, 22 females; mean age, 16.5 years) were collected. Twenty-one canines were palatally impacted (PIC), and 13 were buccally impacted (BIC). Angular measurements of lateral incisors (LIs), first premolars, and the impacted canines positions relative to a 3-dimensional coordinate system and canines' volume, length, and shape of the roots, were compared between the affected and contralateral control sides. The influence of canine position and severity of impaction was examined. Statistics included the paired t test, Wilcoxon signed rank test, and McNemar test. RESULTS: In the PIC group, LIs showed significant mesiobuccal rotation (-17.1°), mesial angulation (8.4°), and buccal root torque (5°) and first premolars mesiobuccal rotation (6.1°). In the BIC group, LIs displayed mesiobuccal rotation (-18°) and significant palatal root torque (-5°). The canine volumes were similar in BICs and slightly smaller in PICs. The lengths were shorter in both, but root hooks were more prevalent in BICs. The severity of impaction affected the measured variables. CONCLUSIONS: The differential position of the adjacent teeth is pathognomonic for PIC vs BIC, and impaction seems to affect canine development. The findings provide evidence-based clinical and radiographical clues for early diagnosis of canine displacement and planning the most efficient treatment strategy. In addition, they support timely orthodontic eruption before the development of the apical third of the root.

Can a Red Wood-Ant Nest Be Associated with Fault-Related CH4 Micro-Seepage? A Case Study from Continuous Short-Term In-Situ Sampling.

We measured methane (CH4) and stable carbon isotope of methane (δ13C-CH4) concentrations in ambient air and within a red wood-ant (RWA; Formica polyctena) nest in the Neuwied Basin (Germany) using high-resolution in-situ sampling to detect microbial, thermogenic, and abiotic fault-related micro-seepage of CH4. Methane degassing from RWA nests was not synchronized with earth tides, nor was it influenced by micro-earthquake degassing or concomitantly measured RWA activity. Two δ13C-CH4 signatures were identified in nest gas: -69‰ and -37‰. The lower peak was attributed to microbial decomposition of organic matter within the RWA nest, in line with previous observations that RWA nests are hot-spots of microbial CH4. The higher peak has not been reported in previous studies. We attribute this peak to fault-related CH4 emissions moving via fault networks into the RWA nest, which could originate either from thermogenic or abiotic CH4 formation. Sources of these micro-seepages could be Devonian schists, iron-bearing "Klerf Schichten", or overlapping micro-seepage of magmatic CH4 from the Eifel plume. Given the abundance of RWA nests on the landscape, their role as sources of microbial CH4 and biological indicators for abiotically-derived CH4 should be included in estimation of methane emissions that are contributing to climatic change.

Overcoming the oral aspects of -self-mutilation: description of a method.

BACKGROUND/AIM: Self-injurious behavior (SIB) is a serious and chronic condition frequently seen in special needs populations, affecting 10% to 17% of individuals diagnosed with intellectual and/or developmental disabilities. A 2.5-year-old infant with SIB, whose presenting symptoms were severe tongue and lip lacerations accompanied by much hemorrhage, is presented here to illustrate the problem and to show how this may be prevented. MATERIALS AND METHODS: An appliance is described which effectively limits the damage caused by SIB and permits rapid healing of existing injuries. RESULTS: The method provides for a stable, retentive, and comfortable device on the infant's undererupted and largely nonretentive crowns of the deciduous teeth as well as for all permanent teeth in children, adolescents, and adults. CONCLUSIONS: The appliance has been successfully employed for the past 10 years in patients with SIB who have attended for treatment in the Special Needs Clinic in our Department.

[Impacted teeth and the six incarnations of resorption]. / Les six formes de résorption associées à l'inclusion dentaire.

There are six distinct types of resorption of dental hard tissue that occur in association with unerupted and impacted permanent teeth. These pathologic entities differ markedly from one another in terms of their aetiology, their treatment and their prognosis. In several of them, the continued existence of the affected tooth may be in danger while in others, conservative treatment may halt the resorption process and provide for a successful outcome. The treatment approach is specific for each type and is entirely dependant on the diagnosis. This presentation will discuss prevalence, aetiology, presenting symptoms and clinical signs, radiographic features, histopathology, differential diagnosis, treatment and prognosis in relation to each of the conditions.

Etiology of maxillary canine impaction: a review.

This article is a review that enumerates the causes of impaction of the maxillary permanent canines, including hard tissue obstructions, soft tissue lesions, and anomalies of neighboring teeth, and discusses the much-argued relationship between environmental and genetic factors. These phenomena have been shown in many investigations to accompany the diagnosis of canine impaction and have been presented as unrelated anomalous features, each of which is etiologically construed as genetic, including the aberrant canine itself. While in general the influence of genetics pervades the wider picture, a guidance theory proposes an alternative etiologic line of reasoning and interpretation of these studies, in which the same genetically determined anomalous features provide an abnormal milieu in which the canine is reared and from which it is guided in its misdirected and often abortive path of eruption.

Surgical Treatment of Impacted Canines: What the Orthodontist Would Like the Surgeon to Know.

When an impacted permanent maxillary canine has been diagnosed, the general practitioner or pediatric dentist thinks in terms of surgery and orthodontics, usually in that order. If there is an existing malocclusion that requires orthodontic treatment, a full orthodontic appraisal is needed for planning the overall mechanotherapy. The orthodontist will undertake a clinical examination. When all the information is collated, a treatment plan will be formulated to resolve the overall malocclusion, which may lead to a decision to extract permanent teeth. The orthodontist is ultimately responsible to the patient for the success of the treatment plan.

Impacted central incisors: factors affecting prognosis and treatment duration.

INTRODUCTION: In this study, we aimed to assess the patient and treatment factors that influence the success rate and the duration of the orthodontic-surgical modality for impacted central incisors. METHODS: The records of 60 consecutively treated patients (64 impacted incisors) were retrospectively evaluated. The success rate and the duration of each stage of treatment were examined in relation to age, sex, etiology of impaction, location of the impacted tooth, and type of surgical exposure performed. Logistic regression analyses were applied. RESULTS: The group consisted of 26 male and 34 female subjects, 7.0 to 21.9 years old; 27 patients had impactions because of root dilaceration, 29 had impactions because of obstruction, and 4 had impactions with unknown causes. The overall success rate was 90.0%. Five of the 6 failures were dilacerated incisors. The average duration of treatment was 21.6 ± 8.7 months. The only factor that significantly increased the duration was the height of the impacted tooth. Dilaceration was related to a longer stage of traction and, in older patients (late mixed and full permanent dentition), to a longer finishing stage. CONCLUSIONS: The orthodontic-surgical treatment of impacted incisors is generally successful, but relatively long. Patients and parents should be warned of the risk of failure and the increased treatment duration, especially for dilacerated incisors impacted high in the alveolus.

Predisposing factors for severe incisor root resorption associated with impacted maxillary canines.

INTRODUCTION: Severe incisor root resorption (SIRR) associated with impacted maxillary canines is rare but has important implications. Early diagnosis and treatment are imperative. In this investigation, we aimed to identify predisposing factors for impacted canine-linked SIRR. METHODS: Clinical and radiographic data of 55 consecutive patients (77 canines) with SIRR of 96 incisors were compared with data from 57 consecutive control subjects (72 canines). The studied variables were age, sex, position of the impacted canine, size of the dental follicle, and incidence of anomalous lateral incisors. RESULTS: Lateral incisors were more often affected than central incisors, and bilateral SIRR was common. When each variable was examined separately, SIRR was significantly associated with female sex, severely mesiodistally displaced and vertically positioned canines in the middle third of the adjacent incisor root, dental follicles wider than 2 mm, and normal lateral incisors. The multivariate statistical analysis showed that the risk for SIRR was significantly higher in female subjects (4.2 times) with enlarged dental follicles (8.3 times) and normal lateral incisors (5.8 times). CONCLUSIONS: SIRR should be carefully screened in female patients with enlarged dental follicles and normal lateral incisors. A greater degree of canine displacement might also be associated with SIRR.

Failure of treatment of impacted canines associated with invasive cervical root resorption.

OBJECTIVES: To propose invasive cervical root resorption (ICRR) as an unrecognized and/or overlooked etiologic factor in the failure of response of an impacted tooth to orthodontic traction and to underline the importance of cone beam computerized tomography (CBCT) for early and accurate diagnosis of ICRR. MATERIALS AND METHODS: Fourteen patients (age 13-21 years) with impacted canines (15 canines) that had failed to respond to orthodontic forces and that exhibited ICRR formed the case series for this investigation. The initial diagnosis, treatment, clinical and radiographic expression of failure, and adverse effects on adjacent teeth were analyzed. RESULTS: Initial diagnosis had been performed on plane radiographs. The orthodontist was absent during surgery in 11 patients. Nine canines had been exposed by open procedures. ICRR was not related to the severity of impaction. Its diagnosis was made on existing radiographs, new films, and/or new CBCT. The severity of the lesions was Class 3 or 4, and the teeth were finally extracted. Loss of anchorage characterized 11 patients. Apical resorption of the roots of adjacent teeth was diagnosed in 9 patients. CONCLUSIONS: ICRR is a frequently undiagnosed or unrecognized cause of failure of orthodontic resolution of impacted canines and should be distinguished from replacement resorption. CBCT should be used for its early detection and accurate assessment of potential damage to adjacent anchor teeth.

Orthosurgical treatment including anchorage from a palatal implant to correct an infraoccluded maxillary first molar in a young adult.

Tooth ankylosis during adolescence and early adulthood can lead to infraocclusion and several interrelated, adverse sequelae at the intra-arch and interarch levels. An orthosurgical treatment modality that includes surgical luxation and immediate orthodontic traction is recommended as a conservative approach in many patients. The key to success in this approach is the timely delivery of relatively heavy and continuous forces to the luxated tooth to prevent its reankylosis. Because high reactive forces are inevitably generated, it is crucial to create a reliable source of anchorage. This report describes the successful use of an osseointegrated orthodontic implant to reinforce the anchorage during the orthosurgical repositioning of an infraoccluded molar in a young adult.

Cone-beam computed tomography and the orthosurgical management of impacted teeth.

BACKGROUND: Three-dimensional (3-D) cone-beam computed tomography (CBCT) has been used to diagnose and treat impacted teeth. The authors describe the benefits of using CBCT to complement plain film two-dimensional (2-D) imaging. METHODS: The authors compare the efficacy of 2-D and 3-D modalities in relation to the relative positions in space of adjacent and overlapping dental units, the existence of pathology in the buccolingual plane and the ability of each to define the orientation of individual teeth. RESULTS: CBCT imaging can be used to interpret buccolingual information in detail, to distinguish and define the extent and depth of root resorption, and to delineate long-axis orientation of unerupted teeth, including root apex location. It is able to synthesize traditional panoramic and cephalometric radiographs. CONCLUSIONS: CBCT permits oral surgeons to visualize the position and surgical anatomy of the tooth as it will be seen in the operating theater and allows orthodontists to plan directional traction. CLINICAL IMPLICATIONS: Unexpected anatomical or pathological findings that are not noted in plain film radiographs and that may obstruct or delay orthodontic treatment until they are eliminated may be found when CBCT is used. Clinical diagnosis of existing pathology can be assessed accurately by using CBCT. In addition, 3-D imaging contributes to more accurate and less traumatic surgical exposure, as well as to more efficient and directionally appropriate orthodontic traction, than does traditional 2-D imaging and thus contributes to faster resolution and better overall tooth prognosis. The use of CBCT occasionally can be the difference between the success and the failure of the treatment plan.

Analysis of failure in the treatment of impacted maxillary canines.

INTRODUCTION: In this study, we aimed to evaluate the reasons for failure of orthodontic treatment for impacted maxillary canines and to recommend measures to overcome them. METHODS: Twenty-eight patients (ages, 17.4 +/- 4.3 years) with 37 maxillary impacted canines were referred after a failed attempt to resolve the impaction. Reasons for failure were analyzed, and corrective measures undertaken. The success rate of the revised treatments and the durations of both treatments were recorded. RESULTS: The mean duration of the failed treatments was 26.2 +/- 17.2 months. The failed treatments were mostly based on plane radiographs, intra-arch dental anchorage, and elastic traction directly to the labial archwire. The major reasons for failure were inadequate anchorage (48.6%), mistaken location and directional traction (40.5%), and ankylosis (32.4%). In several patients, there was more than 1 possible reason for failure. The success rate of the revised treatments was 71.4%, and the mean duration was 14.4 +/- 7.2 months. Repeat surgery was needed for 62.9% of the canines in which corrective treatment was started, mostly to redirect the ligature wires. The corrective measures included the use of 3-dimensional imaging and a change in the direction of traction. Anchorage was reinforced by dental and skeletal means. CONCLUSIONS: Inaccurate 3-dimensional diagnosis of location and orientation of impacted teeth and failure to appreciate anchorage demands were the major reasons for failure in the treatment of impacted canines.

Buccal ectopia of maxillary canines with no crowding.

INTRODUCTION: Buccally displaced canines (BDC) are usually found in crowded dentitions. Nevertheless, a small but significant number of patients with BDC have no crowding. In this study, we compared BDC dentitions with no crowding (BDC-nc), BDC dentitions with crowding (BDC-c), and uncrowded dentitions with normally erupted canines (C). METHODS: The mesiodistal (MD) widths of maxillary permanent teeth, the prevalence of maxillary lateral incisor anomalies, and the dental age were compared in BDC-nc (n = 30; 17 male, 13 female), BDC-c (n = 41; 21 male, 20 female), and C dentitions (n = 40; 20 male, 20 female). RESULTS: No differences in the MD dimensions of the teeth in the BDC-nc and C subjects were found; teeth in the BDC-c group were slightly larger. Only the lateral incisor was consistently smaller in the BDC-nc group. The prevalence of lateral incisor anomalies was markedly increased in the BDC-nc (28.3%) compared with the BDC-c (7.6%) and the C (8.6%) groups. No discrepancies were found in dental age. CONCLUSIONS: These findings suggest that, in addition to a genetically based etiology, buccal displacement in BDC-nc subjects might also be the result of lack of guidance from an adjacent anomalous lateral incisor.

Orthodontic treatment for the special needs child.

The prevalence and severity of malocclusion is especially high in Special Needs individuals. Many have medical limitations to the various procedures that are often needed in the pursuit of excellence from orthodontic treatment and almost all have moderate to severe behavioural problems that make treatment delivery difficult or even impossible to achieve, with any degree of reliability. Nevertheless, the parents are highly motivated to "do the best for their child" and are prepared to become integral members of the treatment delivery team. The present article analyzes the difficulties involved and makes recommendations as to how these may be overcome, based on the authors' published studies in this area and on their broad experience in treating these compromised individuals. Emphasis is placed on the use of pharmacological modalities as the means to providing therapeutic access to many of the more difficult patients. Two case reports are provided to illustrate many of the important principles that pertain to these cases.

Periodontal status of impacted maxillary incisors uncovered by 2 different surgical techniques.

PURPOSE: The aim of this retrospective study was to compare the postretention clinical appearance and the pulpal and periodontal status of surgically exposed and orthodontically aligned impacted maxillary central incisors, treated by 2 different surgical techniques-open eruption (OE) versus closed eruption (CE). PATIENTS AND METHODS: The OE group consisted of 11 patients, age 15 to 38 years. The 11 patients in the CE sample (aged 14-28 years) were selected from a larger group of patients treated by this method, by carefully matching them to the patients in the OE group, in terms of cause and height of impaction. The length of the follow-up period was comparable for both groups (median of 9 years for the CE group and 10 years for the OE group). The clinical and radiographic variables were compared by paired t and chi(2) tests. RESULTS: The only parameters where statistically significant differences between the 2 study groups were found were crown length and bone support; that is, the central incisors uncovered by the OE technique had longer clinical crowns (by a mean of 1.37 mm) and decreased bone support (7.5% less on the mesial side) compared with those treated with the CE technique. Pulp changes with crown discoloration were only seen in the trauma-related group, independent of surgical technique. CONCLUSIONS: The choice of surgical technique in the exposure of impacted central incisors has important implications in the success of the orthodontic treatment of impacted incisors, in the long term, in relation to periodontal support and to appearance.