Transmigrant impacted mandibular canines: a retrospective study of 15 cases

BACKGROUND: Transmigration of mandibular canines across the midline is rare. The authors describe the clinical and radiologic characteristics of patients with transmigrant impacted mandibular canines. METHODS: The authors conducted a retrospective observational study of 14 patients with transmigrant canines. They diagnosed transmigrant canines in all of the patients on the basis of the clinical and radiological findings, and they obtained the data from the patients' case histories and panoramic radiographs. They considered a canine to be transmigrant when one-half or more of its length crossed the mandibular midline. RESULTS: There were 15 transmigrated canines in 14 patients aged 16 to 60 years. Primary canines were present in 10 cases. One case involved a pericoronal infection, two involved supernumerary teeth, one was associated with an odontoma, and in two a pericoronal radiolucency was seen that was compatible with a follicular cyst. Treatment consisted of surgical extraction for eight patients, and periodic clinical and radiologic follow-up visits for six patients. CONCLUSIONS: Radiographic examination is necessary to diagnose impacted transmigrant canines, among other anomalies. Surgical extraction is the treatment of choice for patients with transmigrant canines involving associated pathology. In some cases, the management of asymptomatic impaction can be limited to periodic clinical and follow-up visits. CLINICAL IMPLICATIONS: The absence of the permanent canine within the arch beyond the normal time of eruption suggests the presence of an impacted canine. A transmigrant canine may develop an associated pathology.     

Transmigration of impacted canines: prevalence,management and implications on tooth structure and pulp vitality of adjacent teeth

The aim of this study was to estimate the prevalence of transmigrant canines in a sample of panoramic radiographs of a random Greek population, to classify them and evaluate clinically and radiographically all the implications for adjacent teeth. Panoramic radiographs of 3,586 patients retrieved from eight private practices between 1998 and 2009, were examined. Panoramic radiographs with extracted canines were not included in this study. An impacted canine was considered to be transmigrant when at least part of its length had crossed the midline. Six radiographs exhibited transmigrant canines (0.17% of the total sample of panoramic radiographs), of which four were mandibular and two maxillary. Canine transmigration is a rare phenomenon in Greek population. The impact of transmigrant canines on adjacent teeth varied from inclination, calcific metamorphosis and root resorption to no effect. Orthodontic therapy was the treatment of choice for two of the cases, while in the remaining cases the patients were scheduled for periodic recalls. Clinical and radiographic evaluation and early diagnosis are crucial aids in proper treatment planning.     

Impacted mandibular canines

AIMS: The aim of the present study was to investigate the incidence of impacted mandibular canines, the associated pathology of these teeth, and to classify them. METHODS AND MATERIALS: This is a retrospective cohort study of 5022 panoramic radiographs taken of patients who presented to the Oral and Maxillofacial Surgery Service of the Faculty of Dentistry at Ataturk University in Erzurum, Turkey between January, 1998 and March, 2006. The panoramic radiographs and clinical data were reviewed. Observations were made on the status of missing permanent mandibular canines; retained deciduous canines; side and number of mandibular canines; sex and age of patients; and any other associated pathology or symptoms as well as treatment methods employed. RESULTS: The incidence of mandibular canine impaction is 1.29% in the 5022 individuals of this Turkish subpopulation. A total of 65 patients had impacted mandibular canines with 33 being females and 32 males. In this study 41 impacted mandibular canines were extracted. Twenty-three canines were attached to bonded buttons for orthodontic eruption purposes. After surgical exposure, one impacted canine was transplanted and the others were left in place for observation. CONCLUSIONS: Maxillary canine impaction is more frequent than mandibular canine impaction. Mandibular canine impaction incidence in this study was found higher than in the published literature to date. This result may be evidence of an actual increase of the number of impacted mandibular canine teeth among patients.     

Clinical bone densitometric evaluation of the mandible in removable denture wearers dependent on the morphology of the mandibular cortex

STATEMENT OF PROBLEM: Wide normal variations have been found in the structure and density of the human skeleton, as well as of the mandible. PURPOSE: The objective of this study was to determine whether the mandibular bone mineral density is correlated with the classification of the structure of the inferior cortex on panoramic radiographs in complete and removable partial denture wearers. MATERIALS AND METHODS: The mandibular cortical index of 136 randomly selected complete and removable partial denture wearers was evaluated via panoramic radiographs. The criteria for the mandibular cortical index were as follow: category 1, sharp endosteal margin of the inferior cortex; category 2, semilunar defects; and category 3, thick cortical residues on endosteal margin. Forty male patients (mean age 72.7; range 56 to 84 years) and 96 female patients (mean age 69.7; range 48 to 86 years) participated. With a copper stepwedge and DenEx 2001 computer program, the mandibular bone mineral density was investigated densitometrically on dental panoramic radiographs. Four experienced observers and 6 general dental practitioners made the observations on all panoramic radiographs. All bone mineral density values were expressed in equivalents of the actual stepwedge thickness. An independent t test (alpha =.05) was used. RESULTS: The severity of changes in the mandibular cortex was significantly related to all measured mandibular bone mineral density values (t test: P<.01). Mandibular cortical index category 3 had significantly lower bone mineral density values in all measured regions of interest. Interobserver and intraobserver agreement in mandibular cortical index assessment was excellent. CONCLUSION: Patients having lower bone mineral density values in the mandible have much more porous cortical layer of the inferior border of the mandible.     

Transmigration of mandibular canines: a rare case report and review of literature

Transmigration of permanent mandibular canines is a very rare phenomenon and has no definite etiology. Most of them are asymptomatic, impacted, and commonly involve the left canines. The eruption of transmigrated canines is even rarer. The purpose of this paper was to review the literature on erupted transmigrated mandibular canines and report a rare case of it in a 13-year-old girl with a transmigrated permanent right canine corresponding to the least frequent Mupparapu type 5 pattern.     

Midfacial fractures in dental panoramic radiography

The purpose of the present study was to evaluate the ability of panoramic radiographs to demonstrate facial fractures. Radiographs of eighty-two patients were analyzed retrospectively in cases in which both panoramic and conventional skull radiographs were available. One hundred thirty fractures within the middle third of the facial skeleton were identified, excluding nasal and mandibular fractures. In 64 per cent of the cases structural alterations suggesting fracture were detectable on panoramic radiographs; however, the interpretation of fractures on panoramic radiographs was much less certain than on conventional skull radiographs. The use of panoramic radiographs alone was often inadequate for diagnosis of many fractures outside the mandible.     

Panoramic radiographs: determination of mandibular steepness

The aim of this study was to evaluate the potential of panoramic radiographs to measure mandibular inclination and steepness. Standardized panoramic and lateral cephalometric radiographs were taken for 95 subjects (46 females, mean age 12.4 +/- 1.2 years; 49 males, mean age 12.1 +/- 1.3 years). Mandibular inclination from panoramic radiograph was measured using gonial angle formed by the tangents of the lower border of the mandible and the distal border of the ascending ramus and the condyle. A correlation test was performed to check for similarity between the measurements. The mean values for the gonial angle were 127.3 +/- 6.2 and 125.7 +/- 6.5 degrees measured from the panoramic and cephalometric radiographs respectively. A high correlation between the measurements taken from both radiographs was found (r = 0.83, P < 0.001). Panoramic radiographs are a useful tool for the measurement of gonial angle, which is an indicator of manibular steepness and subsequently mandibular growth direction. The ability to determine growth direction from the orthopantomogram will be useful because majority of dentists request an OPG for patients during routine dental examination. This will enable the dental professional to spot vertical growth problems using a readily available tool.     

Canine ectopia: report of two cases

Transmigration of mandibular canine is a rare elusive phenomenon described in dental literature. The eruption of such transmigrated canines is even rarer. Two rare cases one of midline mandibular canine and the other of transmigrated mandibular canine across the midline and erupted distal to the opposite lateral incisor are presented. The transmigrated canine maintained its nerve supply from the original site. It is suggested that on routine evaluation of orthopantomograms when the dentist finds an excessive mesial inclination of the unerupted mandibular canine at 8-9 years associated with proclination of lower anteriors. increased axial inclination of the unerupted canine and an enlarged symphyseal cross section area of the chin, it is best to keep such a patient under routine evaluation.     

Developmental changes of mandibular permanent canines and premolars in early mixed dentition.

This study investigated the developmental changes of mandibular permanent canines and premolars in early mixed dentition using panoramic radiographs. Positions of cusps and root apices of the teeth relative to the inferior border of mandible were evaluated. The developmental stages of the teeth were divided into three stages. There were few changes in the inclination of the three teeth. The permanent canine began to erupt before stage 2 and the second premolar began to erupt after stage 2. The distance between the inferior border of the mandible and apices of the three teeth was almost fixed in early mixed dentition.     

The vertical heights of maxillary and mandibular bones in panoramic radiographs of dentate and edentulous subjects.

OBJECTIVE: The purposes of this study were to determine the variation in maxillary and mandibular vertical measurements made from panoramic radiographs and to assess differences in measurements between dentate and edentulous jaws. METHOD AND MATERIALS: A total of 192 alveolar ridges (96 dentate and 96 edentulous) were examined. The mean ages of the dentate and edentulous groups were 51.05 and 59.98 years, respectively. Measurements were made from reference lines drawn from anatomic landmarks on standardized panoramic radiographs. RESULTS: In the dentate group, there was no statistically significant difference between men and women in the height of the maxilla. However, the height of the mandible was significantly greater in men than in women. In the edentulous group, the heights of the maxilla at the anterior and first premolar regions were significantly greater in men than in women. In the same group, mandibular heights were also significantly greater in men than in women. Reductions in the height of the edentulous mandible and maxilla were significantly more pronounced in women than in men. The decrease in the vertical height of the maxilla was not statistically significant in men. CONCLUSION: There are differences between the sexes in alveolar ridge resorption after tooth loss.     

Comparison of three radiographic methods used to locate the mandibular canal in the buccolingual direction before bilateral sagittal split osteotomy

OBJECTIVE: Panoramic radiographs, computerized tomography (CT), and conventional spiral tomographic (Scanora, Soredex, Helsinki, Finland) radiographs were compared for their ability to locate the mandibular canal in the buccolingual direction. Furthermore, the relationship between the cortication of the mandibular canal in panoramic radiographs and the location of the canal in both computerized and conventional tomographic radiographs was assessed. STUDY DESIGN: The buccolingual location of the mandibular canal was determined bilaterally in twenty consecutive patients scheduled for bilateral sagittal split osteotomy. The position of the mandibular canal was evaluated by means of panoramic radiography, Scanora, and CT. The three imaging methods were compared for their ability to locate the mandibular canal in the buccolingual direction. The subjective neurosensory deficit of the lower lip and chin on both sides was registered preoperatively and at 4 days, 3 weeks, and 3 months after surgery, and the operative outcome was analyzed in relation to the distance from the mandibular canal to the buccal cortex of the mandible. RESULTS: CT gave better visualization of the mandibular canal than Scanora imaging. Cortication of the mandibular canal on the panoramic radiograph did not serve as a predictor of the proximity of the mandibular canal to the cortices of the mandible. At 3-month follow-up, there were only eight operated sides with abnormal sensation of the lower lip and chin. In seven of these sides, the distance from the mandibular canal to the buccal cortex was less than 2 mm. CONCLUSION: The buccolingual location of the mandibular canal is visualized better with CT than with Scanora or panoramic radiographs.     

Research methods in dentistry 9. Follow-up of permucosal implants in an edentate mandible using panoramic radiography

Panoramic radiographs are frequently used for routine follow-up of mandibular implants. The objective of this study was to determine whether measurement on a panoramic radiograph of the vertical dimension of the mandible near by an implant, using the known implant length as a reference, is a reliable method. In 11 patients, 2 permucosal implants were placed in the anterior part of the edentulous mandible. During the first year after implantation, 2 panoramic radiographs and 2 sets of standardized oblique lateral cephalometric radiographs were made. Oblique lateral cephalometric radiographs are the golden standard for measuring the vertical dimension of an edentulous mandible. The length of the implants and the vertical dimension of the mandible dorsally to the implants were measured on all oblique lateral cephalometric radiographs. The measured and known implant length were used to calculate the image enlargement factor. This factor was used to calculate the real vertical dimension of the mandible. The same measurement procedures were performed on the panoramic radiographs. Using a paired t-test, the calculated values of the vertical dimensions of the mandibles found on panoramic radiographs were compared with the calculated values found on oblique lateral cephalometric radiographs. No statistically significant differences were found. It was concluded that under the described circumstances, panoramic radiographs can be used for reliable measurement of the vertical dimension of the mandible near by permucosal implants.     

下磨牙区种植体尖端与下颌管间安全距离的探讨

目的:探讨下颌磨牙区植入的种植体尖端与下牙槽神经管上缘之间的安全距离。方法:用游标卡尺测量23例患者全景片中的30颗下颌磨牙区种植体长度,除以对应的种植体实际长度,计算全景片中下颌磨牙区垂直放大率(vertical magnification factor,MF);选择种植体尖端至下牙槽神经管上缘间距离小于2mm的8例患者的全景片,测量片中12颗种植体尖端至下牙槽神经管上缘间的距离,除以对应种植体的垂直放大率,计算其实际距离;记录该8例患者有无下唇和(或)颏部感觉异常。结果:①全景片中下颌磨牙区垂直放大率为1.27±0.02;②12颗种植体尖端距下牙槽神经管上缘之间的距离为(1.19±0.33)mm(0.69～1.89mm);③8例接受种植体植入的患者,无一例出现下唇或颏部感觉异常。结论:下颌磨牙区植入种植体的尖端与下颌管上缘之间保存完整的骨壁,是防止损伤下牙槽神经的最关键因素之一。     

Transmigration of impacted mandibular canines--report of 4 cases

Impacted canines are not uncommon in clinical practice, but intraosseous movement of impacted canines crossing the midline (transmigration) is a rare phenomenon. We report 4 cases of mandibular canine transmigration to emphasize the need to supplement periapical radiographs with a panoramic radiographic examination in patients with over-retained deciduous canines or missing permanent canines.     

Radiographic evaluation of third-molar development in a group of Turkish children

The aim of this investigation was to evaluate the crypt formation and calcification of the maxillary and mandibular third molars according to age and gender on panoramic radiographs in a group of Turkish children. Four hundred panoramic radiographs of 188 female and 212 male dental patients, ages six to thirteen years, were examined by two observers. The interrater reliability was tested by Kappa statistics. The earliest age for maxillary third molar crypt formation was eight years; mandibular third molars could be seen radiographically as early as seven years.     

颌骨骨密度和全身骨密度的相关性研究

目的:研究骨质疏松患者与正常对照人群下颌骨相关指标的差异,探讨颌骨骨密度和全身骨密度相关性。方法:应用计算机处理软件对80例健康对照组和40例骨质疏松患者的数字曲面体层片的颌骨骨密度及相关指标测量:牙槽骨骨密度、骨高度、下颌骨下缘皮质厚度(CW)、曲面体层下颌指数(panoramic man-dibular index,PMI)、牙槽骨吸收指数(mandible resorption index,MRI)进行测量分析,并用SPSS12.0进行统计学处理。结果:骨质疏松患者组和健康对照组的CW(3.8vs4.27)、PMI(0.30vs0.33)有显著性差异(P<0.05),而骨高度(10.64vs10.56)、牙槽骨骨密度、MRI没有明显差异(P>0.05)。结论:老年性骨质疏松患者下颌骨骨形态改变明显,全身骨代谢和颌骨骨质的改变有一定相关性。     

Study on the necessity for cross-section imaging of the posterior mandible for treatment planning of standard cases in implant dentistry

OBJECTIVE: To investigate whether cross-section imaging influences the planning and therapy of standard implant cases in the posterior mandible. MATERIAL AND METHODS: In a prospective study conducted over 16 months, the planned treatment (standard implant therapy without bone augmentation procedures in the premolar and molar regions of the mandible) was compared with the postoperative result in 50 randomly selected patients. Clinical examinations and panoramic radiographs were performed pre- and postoperatively, whereas cross-sectional tomography was performed only preoperatively. RESULTS: The vertical magnification factor in the panoramic radiographs was very constant pre- and postoperatively with 1 : 1.27 and in the spiral tomograms with 1 : 1.52. In 11 of 77 implant sites, the mandibular canal could not be evaluated in the spiral tomograms. The additional information from cross-sectional spiral tomography did not influence the original planning in 74 of 77 (96.1%) implant sites. Based on the postoperative panoramic radiograph, the average distance from the tip of the implants to the mandibular canal was 3.04+/-2.06 mm. In two cases (2.6%), transient postoperative altered tactile sensation of the mental nerve was found. CONCLUSION: The information from preoperative cross-sectional spiral tomography has minor impact on treatment planning in standard implant cases in mandibular premolar and molar regions. The clinical examination provides sufficient information for selecting implant diameter and the panoramic radiograph provides sufficient information for implant length selection.     

下颌阻生第三磨牙与下颌管位置的曲面体层X线片和锥形束CT观察

目的 观察分析在曲面体层x线片上人群中下颌阻生第三磨牙(impacted mandibular third molar,IMTM)与下颌管位置关系的类型,并对二者关系密切的病例行锥形柬CT(conc beam computed tomography,CBCT)检查,了解二者实际位置关系.为临床制定IMTM拔除手术方案提供参考.方法 观察390例(645侧)曲面体层X线片,将IMTM与下颌管的位置关系的影像分为3种类型:①无接触类,二者影像无任何重叠或接触;②点状接触类,二者之间影像仅为点状接触;③部分重叠类,二者影像部分重叠或有较大范围接触.统计3种类型的构成比.曲面体层X线片显示IMTM与下颌管影像呈部分重叠或较大范围接触的部分病例行CBCT检查,观察曲面体层X线片IMTM与下颌管关系密切者中,IMTM实际突破下颌管壁所占的比例.结果 390例(645侧)IMTM的曲面体层X线片影像中,无接触类441侧(68.4%);点状接触类149侧(23.1%);部分重叠类55侧(8.5%).对31例(50侧)曲面体层X线片上显示IMTM与下颌管呈部分重叠或较大范围接触的CBCT检查发现,25侧(50%)IMTM突破下颌管壁.结论 ①曲面体层X线片可以排除90%以上IMTM与下颌管关系不密切的病例;②曲面体层X线片IMTM与下颌管影像呈部分重叠或较大范围接触表现的病例有必要行CBCT进一步检查.     

Mandibular lengthening by distraction osteogenesis in children--a one-year follow-up study.

OBJECTIVE: The present study was undertaken to document whether mandibular length could be increased by distraction osteogenesis in children and what happens to the mandibular position 1 year after the distraction. METHODS: Five patients with hemifacial microsomia (four unilateral, one bilateral) had distraction osteogenesis performed to lengthen the mandible. All patients had cephalometric and panoramic radiographs obtained before and 3, 6, and 12 months after the distraction osteogenesis. RESULTS: The total mandibular length (Co-Gn) on the affected side was increased by 11.2 mm after the distraction and remained stable during a 1-year observation period. However, the increased mandibular length tended to move the chin downward (8 mm) more than forward (2 mm) during the same period. CONCLUSIONS: Distraction osteogensis can be used to lengthen the hypoplastic mandible. However, most of the increased mandibular length moved the chin downward more than forward.     

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.