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Intrabony migration of impacted teeth is a rare dental anomaly, which occurs only in the permanent dentition of the lower jaw. The teeth involved in this phenomenon are the mandibular lateral incisor, canine, and second premolar. Migration of the lateral incisor is usually in a distal direction, resulting in transposition with the canine. Migration of the canine is most frequently in a mesial direction, resulting in transmigration across the mandibular symphysis to the opposite side of the dental arch. The second premolar most often migrates distally, sometimes past the gonial angle and as far as the coronoid process. Surgical and orthodontic treatment options are presented for the three intrabony migrating teeth.

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.

Objectives: Prediction of third molar eruption carries significant prognostic importance. There have been various reports of methods to predict the probability of impaction of these teeth. We studied the level of agreement between these three prediction methods., Materials and Methods: a total of 61 patients, mean age 16.4+/-0.98, of Italian origin with initially retained 121 lower third molars were selected for this study. Panoramic radiographs were taken on each subject. For each third molar, the prognosis of eruption was assessed by three different cephalometric techniques: Olive, Ganss, Venta. The Kappa coefficient was used to compare results between the 3 methods (pairwise agreement) for each individual molar, the McNemar test to assess pairwise imbalance., Results: a weak agreement was found between Ganss and Olive, fair between Venta and Ganss and between Olive and Venta. Additionally, the statistical analyses revealed a significant imbalance within the pairwise comparisons., Conclusions: the three methods were not found to be reliable or accurate; perhaps, the method of Castella et al. holds better promise.

Objective: To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs., Study Design: Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar., Results: The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars., Conclusion: The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.

The aim of this study was to test whether the Third Molar Eruption Predictor, developed for panoramic radiographs, can also be applied to periapical radiographs. The Third Molar Eruption Predictor is a transparent device (US patent 5,816,814), not commercially available, and developed for prediction of future eruption or impaction of third molars. The material consisted of periapical radiographs of mandibular third molars taken from the lateral projection without angulation of the central beam. The radiographs taken at the mean age of 20.6 years (SD +/- 1.4 years) were retrospectively available from a four-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. Initially unerupted or partially erupted third molars (n=43) in 28 dental students were analyzed. Clinical statuses of the third molars were available at baseline and four years later. The device was calibrated using the method of simple proportions and Bayes' Decision Theory. The predictions made with the calibrated device were in conformity with the final clinical outcome in 84% of the cases. It was concluded that the Third Molar Eruption Predictor may also be used on periapical radiographs after calibration of the device.

Two cases are presented, each with both unerupted maxillary canines so badly positioned that eruption seemed unlikely. However, over a period of approximately three years, three out of the four initially displaced canines did erupt; the improvements in position being unrelated to whether or not the associated primary canine was extracted. Three out of four primary canines were removed. These cases highlight the difficulties in predicting canine eruption for individual patients.

Primary tooth impaction is quite rare during the development of primary dentition. Various factors contribute to the impaction of a deciduous tooth, including malposition and malformation of the tooth bud, dentomaxillofacial disharmony, tumors, and cysts. This case was a 6-year-old female with complete left cleft lip/palate. A maxillary right second deciduous molar impacting at a high level approximate to the maxillary sinus was noted on the initial visit. To prevent surgical trauma to the surrounding tissue and succedaneous teeth, regular follow-up with radiographic examination was taken every 2 years. After a 7-year long-term follow-up, the impacted second primary molar in the right maxillary sinus had almost completely been resorbed with only about 10% of the original structure left. To the present, the resorption of the impacted deciduous molar seemed to have continued with no major pathological changes. Periodic radiographic examination is strongly advised until the total resorption process is completed.

Resection of the odontogenic region or root transection of normal (impeded) rat lower incisors showed that eruption ceased from 1 to 13 weeks when the base of the resected teeth (87.5%) or of the distal segment of the transected ones (86%) reached the alveolar-crest region. When the operated teeth reached the crestal region, the enamel-related periodontal tissues were absent and the periodontal ligament (PDL) was the only periodontal tissue that remained. The PDL of the crestal region may be considered as mature PDL, showing a length of approx. 5-6 6 mm at the mesial face of the tooth, 4-5 mm at lingual face and 1 mm at distal face; from these limits towards the apical end of the socket the PDL becomes gradually immature. The mature PDL seems not to have a role in the process of tooth eruption. Several factors can be suggested to explain the more frequent retention, at the crestal region of the socket, of impeded rather than unimpeded incisors submitted to the same procedures. The connective tissue that develops between the base of the tooth and the bone that fills the alveolus may have more time to organize itself in impeded than in unimpeded teeth, which erupt at a faster rate; this tissue could support and retain the impeded operated teeth longer than the unimpeded ones. The decrease in the mechanical properties of the PDL in the unimpeded condition may ease the traumatic effects and lead to exfoliation. Eruption might be stopped by the increase in occlusal forces, per unit area of root surface, as the root becomes shorter; this effect is likely to be greater in impeded than unimpeded teeth.

Objective: Develop patient selection criteria and guidelines for the diagnostic work-up for early secondary alveolar bone graft designed to accommodate a lateral incisor in the cleft., Design: A literature review with clinical examples., Interventions: For the majority of cleft lip and palate (CLP) patients, the timing of the secondary alveolar bone graft procedure is devised to accommodate the eruption of the maxillary canine. However, when the lateral incisor is present in the cleft area, a decision may be made to perform early grafting in order to salvage an additional tooth. Appropriate case selection for this intervention is the key for successful dental habilitation in the cleft area., Results and Conclusions: Attempts to maintain the lateral incisor are recommended only if the tooth contributes to the comprehensive orthodontic and restorative patient care and when the presence of a lateral incisor with adequate size, shape, and proper position may be demonstrated. For optimal decision making, the position, form, and periodontal ligament support of the lateral incisor should be assessed. Evaluation of these parameters is based chiefly on radiographic imaging. Occlusal projections and traditional tomography may augment the information available from periapical and panoramic radiographs. However, each of these has benefits and drawbacks that require consideration.

The purpose of this study was to investigate the eruption speed and rate of angulation change of a cyst-associated mandibular second premolar after marsupialization of a dentigerous cyst in preadolescents. Premolars on the cyst and noncyst sides and size of the cyst were retrospectively examined with a total of 42 pairs of normalized panoramic radiographs in 20 patients who underwent neither extraction nor orthodontic traction of the cyst-associated mandibular second premolar after marsupialization. Sixteen premolars at the intraosseous eruption stage in a total of 9 preadolescents without cysts were also examined. The eruption speed and rate of angulation change of the cyst-associated mandibular second premolar were significantly faster than those of the premolars without cysts, and significantly correlated with the diminishing rate of the cyst size, which rapidly decreased for the first 3 months after marsupialization. In addition, the eruption speed of the cyst-associated mandibular second premolar correlated with that of the premolar on the noncyst side, and the rate of angulation change inversely correlated with the level of root formation. The results suggest that a cyst-associated permanent tooth erupts more rapidly regardless of the level of root formation and size and type of the cyst, and the abnormally tilted tooth axis improves more rapidly for the first three months after marsupialization of a dentigerous cyst in preadolescents.

The aim of this paper is to show an occlusal and functional rehabilitation of a lower canine tooth in total osseous inclusion by means of surgical and orthodontic therapy. This rehabilitation is very important for mastication and for the correct function of the temporomandibular joint.

Presented here is a case of 7 years 6 month old child with an apically impacted mesiodens in relation to the developing root of right upper central incisor. The removal of mesiodens was deferred in order to avoid disturbance in the natural development of the upper central incisor. Serial X-rays are presented and case is discussed.

The aim of this study was to investigate the differences between two groups of patients with either erupted or impacted mandibular third molars before and after orthodontic treatment. All patients were treated with Begg appliances following extraction of the four first premolars. The erupted group consisted of 14 subjects and the impacted group 13 subjects. Lateral cephalometric films, peri-apical radiographs, orthopantomographs and orthodontic casts of each subject were taken before and after treatment. Thirteen measurements were carried out on the lateral cephalometric radiographs. The results revealed slightly more vertical growth and a smaller mandibular arc angle in the erupted group at pre-treatment, and also a more upright lower third molar position and slightly greater distance between the distal point of the lower second molars and the centre of ramus (Xi) in the same group. In the course of treatment, mandibular third molars seemed less likely to erupt when the condyle grew vertically. The lesser resorption on the anterior border of the ramus might have played a part in this finding. In addition, a greater mesial inclination of the mandibular third molars might be an indication of the tendency for these teeth to be impacted in the present study.

Ectopic eruption and impaction of canines is a frequently encountered clinical problem. The incidence of impaction ranges between 1% and 3%. The cause of canine impaction can be the result of localized factor(s) or can be a polygenic multifactorial inheritance and associated with other dental anomalies. There are a number of possible sequelae to canine impactions, ranging from loss of space in the arch to resorption of the roots of the neighboring teeth. Although the management of the ectopically erupting teeth necessitates the combined expertise of a number of clinicians, the orthodontist should have the primary responsibility of coordinating these efforts to provide the patient with the optimal treatment options with the most stable and favorable outcome.

Teeth may become impacted when they fail to erupt or develop into the proper functional location. As such, impacted teeth are considered nonfunctional, abnormal, and pathological. The mandibular third molar is the most common tooth to become impacted. The cause of impacted third molars is thought to be inadequate space. Several studies indicate that a change from a coarse, attritive diet to a modern, refined diet has lead to an increased incidence of impacted teeth. Interproximal attrition allows for greater mesial migration of teeth and space for third molar teeth. Teeth that fail to attain a functional position may be pathological and should be considered for removal. The indications for removing impacted teeth can be divided into those of acute or chronic pathology. Impacted third molars are often associated with pain, infection, cyst formation, benign tumors, root resorption, bone loss, periodontal disease, and caries. The decision to surgically remove impacted third molars is often unclear. There are no absolute treatment protocols established. The dentist must consider a variety of factors and make an informed decision with the patient. Most experienced clinicians combine objective data and common sense to arrive at a logical treatment plan. The purpose of this article is to discuss factors related to impacted teeth and help the orthodontist understand the general management of impacted third molars. The decision for surgery will be assisted by an understanding of all of the risk factors associated with impacted teeth and presenting the options to the patient.

Objective: To measure changes in angular position and eruption status of mesially impacted mandibular third molars (M3) during 4-year follow-up period., Study Design: Standardized panoramic radiographs were taken at the start of the study (the average age of the subjects was 19.7 years) and 4 years later. Angulation and degree of impaction of M3 were determined by their sagittal relationships to the adjacent second molars. The impacted M3 were either partially erupted or unerupted., Results: Initial examination showed that among a total of 59 mesioangular M3, 49 (83%) had inclination between 5 and 30 degrees. The proportion of M3 that became upright (zero tilt) was 76% (13/17) with initial angulations of 5 to 10 degrees, 61% (11/18) with initial angulations of 15 to 20 degrees, and 14% (2/14) with initial angulations of 25 to 30 degrees. None of the M3 originally presented at 35 degrees or more became upright, but an average decrease of 12 degrees in angulation was registered. In total, 26 M3 of 59 (44%) became upright during the follow-up period. Initial examination of levels of eruption showed that among 59 M3, 13 (22%) were partially erupted and the rest were unerupted. Of the 46 M3 initially unerupted, 17 (37%) became fully erupted and 7(15%) erupted partially during the 4-year follow-up. Of the total sample, 25 (42%) had erupted to full occlusion during the observation period., Conclusion: A significant proportion of mesially impacted mandibular M3 had changed their angulation and became fully erupted by the time the individual reached 24 years of age. Positional changes and eruption of impacted M3 are unpredictable phenomena.

This study was designed to create a transparent device to be superimposed on a panoramic tomogram taken of a patient at age 20 years to make predictions of future eruption or impaction of lower third molars. The device was developed from data on 40 lower third molars initially retained at age 20 years; one half of these remained impacted, and the other half of them erupted by age 26 years. Tracings were made from panoramic tomograms taken at age 20 years. The critical point for prediction in the overlay was the intersection of a horizontal reference line and the anterior border of the ascending ramus. To estimate this critical separation line, Bayes' Decision Theory was used. The sum of false negatives and false positives was least at a distance of 14.5 mm from the distal surface of the second molar. Mesial from this point, the probability of impaction was 76%; distal from this point, the probability of eruption was 72%. Tested against 35 initially unerupted lower third molars, the predictions made by the device and the actual clinical findings were in conformity in relation to 97% of the test teeth. It could thus be concluded that the method was simple to use and may prove a good addition for predicting lower third molar development.

The records of a consecutive series of 72 patients who had undergone excisional exposure of one or both palatally displaced canines were reviewed. The purpose was to ascertain whether the canine(s) erupted spontaneously following surgery, whether orthodontically-assisted eruption was required or whether the procedure failed completely indicating the need for re-exposure. The results of the study suggest that the majority of canines will erupt once exposed and of those that fail to erupt completely most will still remain exposed to a sufficient extent to allow attachments to be bonded to the palatal surface.

Panoramic radiographs of 1834 patients older than 21 years were evaluated for the prevalence of impacted teeth at different ages. The frequency of impacted teeth by age was constant, that is, the presence of completely impacted teeth could not be related to age. The interrelationship between the angulation of impacted teeth and the existence of adjacent teeth was studied in individuals older than 61 years. The angulation of most of the completely impacted teeth in the upper-third molar region was horizontal when adjacent teeth were not present, whereas impacted teeth in the upper-third molar region showed vertical angulation when adjacent teeth were present, suggesting that vertically impacted teeth may become exposed by bone resorption or infection and should be removed. The angulation of impacted lower third molars was horizontal irrespective of the presence of adjacent teeth. It appears that the interrelationship between the angulation of completely impacted teeth and the presence of adjacent teeth is different between the upper and lower third molar regions. The angulation of completely impacted teeth and the presence of adjacent teeth should be included in those criteria which determine whether or not completely impacted teeth should be removed.

The authors present a study on the cementum of impacted teeth. It was not possible to correlate the thickness of the cementum and the age of the patients. Significant differences were found, on the other hand, between the thickness and distribution of the cementum in different teeth. Third molars showed in almost all cases an increase in the thickness of cementum.

Long-term follow-up orthopantomographs of 251 adult orthodontically treated former patients showed 113 clinically asymptomatic impacted third molars in 58 patients. Radiographic assessment revealed contact of impacted third molars with the second molars, resorption of maxillary and mandibular second molars, as well as pathologically widened pericoronal spaces of the maxillary and mandibular third molars. The comparison of the sagittal third molar position in 52 impacted teeth revealed a sagittal change in all third molars from post-treatment to follow-up: maxillary and mandibular third molars had rotated to a more upright position and showed an increase in mesio- or distoangulation or a change of axial inclination. The lack of predicting factors such as age, period of impaction, extent of space deficiency, developmental stage, level of eruption, and bone conditions leads the authors to recommend that former orthodontic patients be recalled at regular intervals for assessment of changes in the condition and position of erupting or impacted third molars.

Transmigration of impacted mandibular cuspid to the opposite side seems unhypothetical due to the presence of symphyseal cartilage. Two such rare cases of extreme transmigration were radiographically discovered when patient reported for orthodontic therapy.

The purpose of this study was to examine functional occlusion of impacted maxillary canines which had been moved orthodontically into the line of occlusion. Examinations were performed on both patients and on an articulator, which was adapted to correspond to the axiographical findings. Functional contacts on the working side during lateral movement of the mandible were found in all orthodontically aligned impacted canines. Half the aligned teeth were involved in canine guidance, half in group function. Balancing side interferences were detected in 22% of the cases. The result of this study revealed a nearly identical function in the aligned canines when compared with the spontaneously erupted canines on the other side of the same maxilla. This became apparent during lateral excursion of the mandible. The angle of mesiodistal inclination of the tooth central axis with an occlusal plane was 84 degrees for aligned and 82 degrees on average for the spontaneously erupted canines.

The removal of impacted third molar teeth ranks as the commonest procedure in the practise of oral and maxillofacial surgery. It is the purpose of this review article to present the major controversies and correct some of the misconceptions associated with third molar surgery. This paper deals primarily with the discussion of the indications for the removal while part II describes the influence of a variety of factors upon the outcome of third molar surgery.

GPA cement was tested as an alternative to conventional surgical dressings in connection with radical surgical exposure of teeth. The material comprised 29 patients (mean age 14 4/12 years) with 35 impacted maxillary canines in palatinal position. Soft tissue and bone covering one fifth to one quarter of the tooth crown were removed. The enamel was cleaned with physiological saline and dried with gauze pads. Ketac-Fil was applied using the ESPE Aplicap system. Application stopped when the level of intact mucosa was reached. At control after 1-2 weeks (35 teeth) all packs were in place. Healing conditions were normal and soft tissue regrowth was not seen. At control after 1-6 months (23 teeth) 10 dressings were in place. Surrounding mucosa was healthy regardless of the presence of absence of pack. Soft tissue regrowth was not seen. 6-16 months postoperatively (12 teeth) all packs except 1 had been lost. Soft tissue regrowth in combination with eruption failure was seen in 2 patients. In these cases the packs had been lost soon after the first control, i.e. before healing had been completed. The results indicate that GPA cement can be recommended as an alternative to conventional surgical dressings in connection with radical surgical exposure of teeth.

To determine radiographic features by which one could estimate whether lower third molars are likely to erupt after the age of 20 years, university students with a total of 84 unerupted or partially erupted lower third molars were followed up. Five radiographic features of each third molar were measured from the panoramic tomogram taken at age 20 years, and the status of third molars was examined for a second time at age 26 years. The results showed that the lower third molars that did erupt after the age of 20 years were initially: 1) root formation complete; 2) impacted in soft tissue; 3) vertical; 4) placed at the same occlusal level as the neighbouring second molar; 5) showed sufficient space between the ramus and the second molar. In contrast, the teeth that remained impacted at the age of 26 years showed such initial features as: 1) incomplete root formation; 2) embedding in bone; 3) mesioangularity; 4) situated at the cervical level of the neighbouring second molar. It was concluded that a panoramic tomogram taken at age 20 years revealed radiographic features on which an estimation of future eruption of mandibular third molars could be based.

A representative sample comprising 1418 women from five age strata was examined by means of panoramic radiography. The prevalence of impacted teeth and the frequency and type of pathology associated with the impacted teeth were assessed. About 8% of the total sample had one or more impacted teeth. Among those, pathological conditions were found in 16%. Most were moderate and consisted in most cases of a slightly widened follicle or resorption of the crown. A new examination 12 yr later revealed unchanged conditions in 85% of the cases. The changes that had occurred were generally small.

Eruption disturbances of permanent molars may become clinically and radiographically manifest as impaction, primary retention or secondary retention. This may result in clinical problems such as malocclusion and loss of neighboring teeth due to caries and periodontal disease. Which of these disorders will develop, depends primarily on the eruptive stage. Factors that may interfere with the eruptive stages (i.e. follicular growth, pre-emergent eruptive spurt, postemergent eruptive spurt, juvenile occlusal equilibrium, circumpubertal occlusal eruptive spurt, adult occlusal equilibrium) and the clinical consequences of that interference are reviewed. Treatment recommendations are given.

The pain experienced after 116 operative removals of mandibular third molars was studied in a homogeneous group of patients consisting of 85 healthy university students. Pain was recorded daily on a visual analogue scale during the postoperative week. It was shown that preoperative inflammation and the difficulty and duration of the operation increased the intensity of pain.

A 9 year old girl presented an impacted lower right 2nd premolar which not only was in horizontal position, but its crown was directed lingually. As a lower right 2nd premolar was in such a position that normal eruption was impossible, the deciduous predecessor was extracted at 9 years of age, and then sufficient space had been created for the lower right 2nd premolar to be erupted, and the eruption of it was observed for about 2 years. 2 years later, radiographic indication showed that no spontaneous eruption of a lower right 2nd premolar was to be expected. At 11 years of age, surgical exposure and traction of a lower right 2nd premolar was attempted. When the lower right 2nd premolar was upright, its root formation was in the 1st stage of root developmental stages according to Moorrees et al. Follow up radiographic observations on surgical exposure and traction of a lower right 2nd premolar 3 years later revealed the following results: 1. The root development went on to amount to about 90 percent of the root formation of the other tooth concerned without the curvature of the root. 2. Lamina dura and periodontal space were normal. The continued root formation was narrowing the root apex and the pulpal tissue of apical foramina was continuous with the periodontal space surrounding the root. 3. Bone deposition occurred at the alveolar crest and the latter was recontoured normally. The interdental and inter-radicular trabecula were good. As based on these results, normal development of the root of a lower right 2nd premolar with normal periodontium can be anticipated. Clinically, the lower right 2nd premolar had completely erupted and was in normal position on the arch and in occlusion. Color, vitality and mobility were normal. Periodontal support was good. The above-mentioned findings give support to the possibility that "early treatment" enables the impacted tooth to correct.

Acute pericoronitis is a painful, debilitating infection that is most commonly found among young adults with erupting mandibular third molars. Prophylactic removal of third molars to prevent this disease has been advocated, but this procedure requires an accurate description of the third molar at highest risk for this infection. Clinical and radiographic measurements were compared in 25 diseased subjects and 109 normal subjects. Of 10 variables significantly related to the presence of acute pericoronitis, stepwise discriminant analysis selected 4 variables that produced a canonical correlation coefficient of 0.71. In clinical terms, these variables described the tooth at highest risk for acute pericoronitis as a fully erupted, vertical mandibular third molar that is in contact with the adjacent second molar, at or above the occlusal plane, and partially encapsulated by soft or hard tissues. Prophylactic treatment of these third molars is highly recommended.

Upper cuspid impaction is a serious problem that occurs with sufficient frequency to justify diagnosis and intervention as early as a dental age of 8 years. Screening consists of identifying patients who lack a normal cuspid bulge on palpation, with follow-up radiographic evaluation where indicated. Selective removal of deciduous cuspids is a suggested interceptive measure in Class I uncrowded malocclusions.