Ankylosis of Permanent First Molar: Diagnosis by Cone Beam Computed Tomography / Anquilosis del Primer Molar Permanente: Diagnóstico por Tomografía Computarizada con Haz Cónico

ABSTRACT: Ankylosis is an anomaly of tooth eruption characterized by the fusion of cementum and alveolar bone, and may affect from small regions to the entire root surface. Clinical assessment combined with imaging exams can aid diagnosis. Radiographic testing enables assessing only proximal regions of possibly affected roots. Whereas cone beam computed tomography (CBCT) allows a three-dimensional assessment of axial, coronal, and sagittal planes of all dental extension, eliminating thus overlapping images and helping to confirm the correct diagnosis. The present study contains a case report of a male patient with ankylosis in tooth 16 diagnosed by CBCT, aiming at providing information for dentists about this anomaly, its characteristics and situations in which CBCT should be indicated.

RESUMEN: La anquilosis es una anomalía de la erupción del diente caracterizada por la fusión de cemento y hueso alveolar, y puede afectar desde pequeñas regiones hasta toda la superficie de la raíz. La evaluación clínica combinada con los exámenes de imagen puede ayudar a diagnosticar esta anomalía. Las pruebas radiográficas permiten evaluar sólo las regiones proximales de las raíces posiblemente afectadas. La tomografía computarizada de haz de cono (CBCT) permite una evaluación tridimensional de los planos axial, coronal y sagital de toda la extensión dental, eliminando así las imágenes superpuestas y ayudando a confirmar el diagnóstico correcto. En el presente estudio se presenta un reporte de caso de un paciente con anquilosis en el diente 16 diagnosticado por CBCT, con el objetivo de proporcionar información para los dentistas sobre esta anomalía, sus características y situaciones en las que debe indicarse la CBCT.

Finite element analysis of bone stress after SARPE.

PURPOSE: This study investigated stress distribution in maxillas that underwent surgically assisted palatal expansion (SARPE). MATERIALS AND METHODS: Five maxillary models were built: no osteotomy (M1), Le Fort I osteotomy with a step in the zygomaticomaxillary buttress (M2), Le Fort I osteotomy with a step in the zygomaticomaxillary buttress and the pterygomaxillary disjunction (M3), Le Fort I osteotomy without a step (M4), and Le Fort I osteotomy with pterygomaxillary disjunction and no step (M5). Displacement coherence and maximum stress (MS) analyses were used for all models. RESULTS: Areas of tension spread to the maxilla and the region between the alveolar ridge and the palate and a critical point in the median suture for M2, M3, M4, and M5. In M2 and M4, MS spread farther toward and over the pterygoid process, contrary to what was found in M3 and M5. M3 had a better performance than the other models, and the tensile stress was interrupted by the posterior osteotomy, thus avoiding possible damage to the sphenoid bone or difficulties in expanding the posterior region of the maxilla. CONCLUSIONS: The steps in the zygomaticomaxillary buttress and the pterygomaxillary disjunction seem to be important to decrease the harmful dissipation of tensions during SARPE.

Marsupialization facilitates eruption of dentigerous cyst-associated mandibular premolars in preadolescent patients.

PURPOSE: The purpose of the present study was to investigate the eruption of dentigerous cyst (DC)-associated mandibular premolars after marsupialization in preadolescents. PATIENTS AND METHODS: The present study was a retrospective cohort study of preadolescent patients with DCs who were treated as outpatients at the Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. For our study, the data from these patients were collected, and the eruption of the premolar teeth, along with related factors, such as the interval to eruption, cusp depth, angulation, cyst size, and eruption space, were analyzed for the cyst group compared with the noncyst control group. RESULTS: The mean age of the patients was 9.1 years. All teeth associated with DCs erupted successfully after marsupialization. The follow-up panoramic radiograph showed that the cysts had disappeared and had been replaced by regenerated bone. The initial panoramic radiograph showed the angulation of the teeth in the cyst group had a significantly larger inclination angle than did the teeth in the noncyst group (P < .05). However, no significant difference was found for cusp depth, root formation, or space measurement. The gender, age, cusp depth, angulation, and eruption space were not factors influencing the eruption of the DC-associated tooth for preadolescent patients in the present study. In addition, the cyst-associated teeth took less time to erupt than the teeth in the control group. CONCLUSIONS: The results of the present study suggest that DC-associated mandibular premolars can erupt spontaneously after marsupialization in preadolescents.

An ectopic tooth concealing an odontogenic myxoma.

UNLABELLED: This case report presents a 13-year-old girl who attended an orthodontic clinic for an ectopic UR5. After investigation, a diagnosis of an odontogenic myxoma was made and the tumour was excised. A panoramic radiograph taken almost two years earlier for another dental problem was found to show an ectopic UR5 associated with a subtle radiolucency. Odontogenic myxomas may be of higher frequency than once thought in the paediatric population and therefore should always be considered in the differential diagnosis of any intraosseous radiolucency. Any radiolucent area associated with an unerupted tooth should be investigated further or closely followed up. CLINICAL RELEVANCE: The odontogenic myxoma is a rare but potentially serious benign tumour of the jaws.

A conservative approach in the management of inflammatory dentigerous cyst in transitional dentition: a case report.

Dentigerous cysts are benign odontogenic cysts that develop from the reduced enamel epithelium related to the crown of an unerupted and/or impacted tooth. Inflammatory dentigerous cyst is a variety of dentigerous cyst that is mostly found in the mixed dentition, and the treatment modalities range from enucleation to marsupialization. By extracting the infected primary teeth, opening the cyst, and ensuring continuous drainage, spontaneous eruption of the involved permanent teeth occurs into the dental arch even if they are severely dislocated. The purpose of this report is to describe the successful treatment of a large dentigerous cyst by conservative surgical management.

Inverted impaction of a mandibular premolar associated with a dentigerous cyst: report of a case.

UNLABELLED: Inverted impaction of mandibular premolars is reported to be rare; its prevalence has not been quantified. Here we report a case in which a 12-year-old female presented with an inverted impacted manibular premolar associated with a dentigerous cyst. The likely aetiology and management of this condition is discussed. CLINICAL RELEVANCE: This case highlights the need for clinicians to be aware of the rarer causes of apparent absence of teeth from the arch and the importance of taking radiographs prior to treatment planning.

Biologic response of rapid tooth movement with periodontal ligament distraction.

INTRODUCTION: Length of treatment is a complaint of many orthodontic patients. The purpose of this study was to evaluate the security and feasibility of rapid tooth movement with periodontal ligament distraction. METHODS: Eight male beagles, aged 13 to 16 months, were used in this study. Extraction of the mandibular second premolar and alveolar surgery to reduce the osteal resistance on the mesial side of the extraction socket were performed on the experimental side. Then a device was placed to distract the first premolars distally on the experimental side; on the control side, the first premolars were distalized with nickel-titanium coil springs. The beagles were killed in the first, second, fourth, and eighth weeks after orthodontic force application. RESULTS: The first premolar on the experimental side moved more rapidly than that on the control side (P <0.05). Histologic data indicated that more new bone was deposited on tension area of the experimental side than on the control side. Active and extensive bone resorption in the compressive area and bone deposition in the tension area were observed on the experimental side. CONCLUSIONS: These results suggest that the periodontal ligament can be rapidly distracted without complications. The rapid orthodontic tooth movement by distracting the periodontal ligament cannot be emulated by current conventional orthodontic concepts and methods.

Eruption prediction of mandibular premolars associated with dentigerous cysts.

OBJECTIVE: A tooth with a dentigerous cyst (DC) does not always erupt by marsupialization. The eruption duration and conditions of DC-associated premolars were examined to predict such eruption following marsupialization. STUDY DESIGN: The eruption and conditions including depth, root formation, inclination, and eruption space were examined retrospectively in 21 DC-associated mandibular premolars using dental and panoramic radiograms. RESULTS: Fifteen of 21 premolars erupted half within 3 months and all 15 erupted completely within 10 months after marsupialization, without orthodontic traction. The age of the patients, tooth depth, and inclination were significantly different between the erupted and non-erupted groups, whereas there was no significant difference in the root formation or the eruption space between the 2 groups. CONCLUSIONS: The successful eruption of a DC-associated premolar can be predicted within 3 months after marsupialization. Furthermore, the eruption may be affected by the patient's age, tooth depth, and tooth inclination.

Expression of osteocalcin during surgically assisted rapid orthodontic tooth movement in beagle dogs.

PURPOSE: To investigate the expression of osteocalcin during rapid orthodontic tooth movement aided by alveolar surgery in beagle dogs. MATERIALS AND METHODS: Eight male beagles were used, and bilateral mandibular second premolars were extracted for distalization of the first premolars against the third premolars by orthodontic NiTi coil spring with a force of 100 gm. Right and left mandibular sides were randomly assigned to experimental and sham sides, and alveolar surgery was performed only on the experimental side to reduce the osteal resistance on the mesial side of the extraction socket. Distance of tooth movement was measured once a week during the first 4 weeks. Two beagles were sacrificed after 1, 2, 4, and 8 weeks of orthodontic force application, and expression of osteocalcin was demonstrated by immunohistochemistry and quantified with computer-aided image analysis. RESULTS: The average total movement of the first premolars in 4 weeks on the experimental side (1.868 +/- 0.022 mm) was approximately double that on the sham side (1.008 +/- 0.057 mm). As regards the average total anchorage loss, no significant difference (P > .05) was revealed. Dynamic osteocalcin concentrations presented at 4 time periods (P < .05). The staining intensity of osteocalcin on the experimental sides was higher than the corresponding sham sides, and that on the compression sites higher than the corresponding tension sites (P < .05). CONCLUSIONS: The results suggested that alveolar surgery might serve as an effective and safe way to accelerate orthodontic tooth movement, and promote the rate of bone remodeling as revealed by the expression of osteocalcin.

Transmigration of mandibular second premolar in a patient with cleft lip and palate: case report

Disturbances involving abnormalities in tooth eruption are named ectopia. Transmigration is the name assigned to ectopia in the presence of teeth in areas distant from the alveolar process. Initial angulation of the tooth bud of the second premolar and premature loss of permanent mandibular 1st molars can influence the distal migration of the second premolar. Some studies have observed that ectopic teeth can be found in a variety of places around the oral cavity and also in other areas of the human body. There are records of teeth in the maxillary sinus, mandibular condyle, coronoid process, mandibular angle, orbit, palate, mentum and also the skin. The prevalence of tooth abnormalities is higher in children with cleft lip and palate compared to children without clefts. This paper presents a case report of migration of the mandibular left second premolar in a patient attending the Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo (HRAC/USP), Brazil. Migration of the mandibular left 2nd premolar was confirmed by 8 panoramic and 1 periapical radiographs obtained during patient's treatment between 1978 and 2002, which were available in the files of the Department of Dental Radiology of HRAC/USP. It can be assumed that distal migration of the mandibular left 2nd premolar is not associated with presence of cleft lip and palate; observation of these two events in a same patient is rare, since no similar reported cases were found in the literature.

Panoramic findings for predicting eruption of mandibular premolars associated with dentigerous cyst after marsupialization.

PURPOSE: The purpose of this study was to investigate the eruption of mandibular premolar teeth associated with dentigerous cysts. PATIENTS AND METHODS: A total of 60 cyst-associated teeth in the mandibular premolars were examined retrospectively by using normalized panoramic radiographs. The subjects were divided into 2 groups: the erupted group, in which the teeth had erupted spontaneously after marsupialization, and the nonerupted group. Patient age, as well as impacted premolar angulation to the adjacent teeth axes, the cusp depth, space/tooth size, eruption period and cyst size, as measured on initial images, were used as parameters. RESULTS: Using a logistic model of our data, we found that patient age less than 10 years, cusp depth less than 5.1 mm, angulations less than 25 degrees, and space/tooth size greater than 1.0 enhanced the success of eruption. CONCLUSION: Our findings present predictors of successful eruption of impacted mandibular premolars associated with dentigerous cysts after marsupialization.

Biomechanical evaluation of Le Fort I maxillary fracture plating techniques.

PURPOSE: This study used a biomechanical model to examine fundamental questions about rigid plate fixation treatment for maxillary Le Fort I fractures. Specifically, we sought to elucidate the principal strain patterns generated in miniplates and bite force transducers secondary to all masticatory forces, as well as the amount of permanent deformations incurred due to these loading forces. MATERIALS AND METHODS: Forty polyurethane synthetic maxillary and mandibular replicas were used to simulate the mandible and maxilla. Ten replicas were controls (group A). The other 30 were divided into 3 groups (10 each), according to the fixation techniques of 3, 2, and 1 miniplates each side (groups B-D), that were osteotomized in the Le Fort I fracture line on the maxilla. Different forces of masseter medial pterygoid, temporalis, and lateral pterygoid muscles were loaded onto the replicas to simulate different functional conditions (anterior incisor, premolar, and molar clenching). Rosette strain gauges were attached at predefined points on the plates and the bite force transducer to compare the stability and bite force of the different fixation methods for maxillary Le Fort I fractures. RESULTS: Statistically significant differences were found for the deformation of the plates among fixation techniques. The order of stability for each technique was: group B greater than group C greater than group D. In regard to bite force, no difference was found between those found with group A and group B (P > .05), whereas the bite forces of groups C and D were less than those of group A (P < .05). CONCLUSIONS: The fixation of 3 miniplates on each side provides sufficient stability and restores the bite force to the level of the intact maxilla. "The ideal fixation" with 2 miniplates on each side restores 90% of the bite force, and there were more deformations of the miniplates with the "ideal fixation" compared to those found with group B. Group D fixation produced the worst effects for the treatment of maxillary Le Fort I fractures with a weak bite force and insufficient stability.

Unicystic ameloblastoma in a child: a differential diagnosis from the dentigerous cyst and the inflammatory follicular cyst.

Unicystic ameloblastoma (UA) is a benign epithelial odontogenic tumor of the jaws with an aggressive potential that commonly occurs in children. This cystic odontogenic neoplasm is generally asymptomatic and found during routine radiographs. The purposes of this report were to describe a case of UA involving the crown of the unerupted right mandibular second premolar in an 11-year-old girl under orthodontic treatment, and discuss its diagnosis and radiographic and microscopic findings, emphasizing its distinction from the dentigerous cyst and the inflammatory follicular cyst.

Comparison of different fixation methods following sagittal split ramus osteotomies using three-dimensional finite elements analysis. Part 1: advancement surgery-posterior loading.

The purpose of this study was to evaluate the mechanical behavior of different fixation methods used in bilateral sagittal split ramus osteotomy (BSSRO). Part 1 comprises of the results of the analysis for mandibular advancement, four different fixation configurations of six hole fragmentation mini plates with monocortical screws and lag screws and posterior loading conditions in the molar and premolar region. The finite element analysis method (FEA) appears suitable for simulating complex mechanical stress situations in the maxillofacial region. The mechanical behavior of selected lag screws with linear or triangular configuration and double parallel or single oblique six hole mini plates with monocortical screws were compared by FEA after 5 mm BSSRO advancement procedure. Four separate three-dimensional finite element models of the mandible were created to simulate the BSSRO and corresponding fixation methods. These models consisted of 122,717 elements and 25,048 nodes. The mechanical parameters of the materials studied were adopted from the literature or were based on manufacturer's information. 500 N posterior occlusal loads were simulated on the distal segments. The commercial finite element solver MSC Marc software was utilized to calculate the stress fields on both the segments and fixative appliances. It was concluded that the use of 2.0mm lag screws placed in a triangular configuration following the BSSRO advancement surgery provides sufficient stability with any rotational movement and less stress fields at the osteotomy site, when compared with the other rigid fixation methods used in the current study.

Tooth development included in the multifocal jaw lesions of Langerhans cell histiocytosis.

Many cases demonstrating the oral manifestations of Langerhans cell histiocytosis (LCH) have been reported; however, tooth development in jaw lesions has rarely been mentioned. This paper reports the case of a 3-year-old Japanese girl with LCH suffering from multiple osteolytic lesions of the skull and jaw bones. She was referred to our paediatric clinic because of swelling of the mucogingival folds in the upper and lower primary molar regions. The patient responded well to steroid therapy and the osteolytic lesions resolved. There was an accompanying development of permanent tooth germs included in the lesions. Langerhans cell histiocytosis in children usually has a long-term clinical course and paediatric dentists should be involved with oral health care for affected patients.

Effect of LED curing on the microleakage, shear bond strength and surface hardness of a resin-based composite restoration.

To determine the effect of Light emitting diode (LED) curing on dental resins, microleakage, shear bond strength and surface hardness of a dental composite cured with different LEDs were determined and compared with conventional halogen curing. For microleakage, Class V cavities were restored with Esthet-X, divided into groups, and exposed to one of the curing protocols (Elipar Freelight in soft start and standard modes; Ultra-Lume 2; Spectrum 800). Standard dye penetration tests were performed and the data summarised in a 2-way contingency table of observed frequencies. The Chi-square test was used (p<0.05) to test for significant differences between the lights. For surface hardness, samples of Esthet-X were exposed to the light-curing units (LCUs). Vickers hardness was determined on the upper and the bottom surfaces. Data was subjected to statistical analysis using ANOVA (p<0.05). Shear bond strength was determined using a push out method. Comparisons (ANOVA, p<0.05) were made between the different curing protocols. No significant difference in microleakage could be demonstrated between the different LCUs at the enamel side (p=0.60). At the dentin side only the Elipar Freelight (soft start), could significantly reduce microleakage (p<0.01). The hardness score for the halogen light was significantly lower than for the LED lights (p<0.01). The Spectrum 800 and the Elipar Freelight (soft start) have significantly higher shear bond strengths than the others (p<0.01). It was concluded that the LED source is more efficient for a comparable overall power output.

Orthodontic assisted tooth eruption in a dentigerous cyst: a case report.

In an orthodontic practice, it is common to deal with impacted teeth, which are one of the most difficult situations dealt with by dentists. This case report describes the surgical and orthodontic management of the impacted teeth in a large dentigerous cyst. In the initial stage of treatment, the cyst was marsupialized over 7 months. After decompression of the cyst, spontaneous eruptions of the impacted tooth were noticed. Then, they were orthodontically brought into the proper occlusion.

[Tooth transposition: results of an enquiry among practitioners]. / Les transpositions intra-maxillaires: résultats d'une enquête auprès des praticiens.

A questionnaire was sent to orthodontists in order to analyse transpositions of teeth and their treatment. The results of this study confirm that most transpositions are maxillary canine/premolar transpositions. These transpositions were found to be often associated with other dental abnormalities (such as agenesis and peg-shaped laterals). Considerable evidences supports they are genetic in origin, but, in accordance with the demands of evidence-based science, further study is needed to prove it. The results suggest that most practitioners try to correct transposition despite the many difficulties involved. Early diagnosis did not reduced treatment time nor diminish difficulties.

Migration following crown-lengthening procedure--a case report.

Periodontal surgery may be accompanied with some postoperative complications such as pain, swelling and sloughing, purulence or infection, transient bacteremia, nerve trauma, and hemorrhage. In general, a resective surgical intervention may implicate reduction in the attachment apparatus. Migration as a postoperative complication has never been addressed in the literature. This paper presents a case report detailing migration of a tooth, following a surgical preprosthetic clinical crown-lengthening procedure, which was repositioned using adjunctive orthodontics with a removable maxillary modified Hawley appliance. It is incumbent upon the dentist to examine meticulously the occlusal status of the teeth prior to a planned surgical intervention and to take measures preventing any possible tooth migration during the healing process. Failure to achieve occlusal and intra-arch stability may lead to undesired tooth movement in the arch postsurgery, affecting future prognosis and complicating any planned prosthetic work.

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.