Mesiodens: a radiographic study in children

We analyzed the frequency and radiological features of mesiodens in a group of children in Turkey. The study was based on a radiographic review of 23,000 pediatric patients (male: 12,667 female; 10,333) who visited the Department of Oral Diagnosis and Radiology during the period 2003-2005 (3 years). The presence of an unerupted supernumerary tooth, or tooth bud between the 2 central incisors or as unilateral or bilateral teeth in the midline of the maxilla was noted as mesiodens on radiographs. Eighty-five cases of mesiodens in 69 patients were found. Complete documentation, including radiographs, for these 69 patients were studied and analyzed. In addition to gender and age, the following information about the mesiodens was recorded: 1) number; 2) shape; 3) position; 4) complications caused by the mesiodens; 5) treatment. Of the 69 patients, the ratio of boys (47 cases) to girls (22 cases) was 2.1:1. Fifty-three (76.8%) of the children had 1 mesiodens, and 16 (23.1%) had 2 mesiodentes bilaterally to the midline. Of the 85 mesiodentes, 67 (78.8%) were fully impacted, 6 (7%) were partially erupted, and 12 (14.1%) were fully erupted. Most of the mesiodentes (55.2%) were found in the vertical position, followed by inverted position (37.6%), and horizontal position (7%). The main complications were delayed eruption of the permanent incisors (38.8%), maxillary midline diastema (17.6%), axial rotation or inclination of erupted permanent incisors (16.4%), and resorption of the adjacent teeth (4.7%) The prevelance of mesiodens has been estimated to be 0.15% to 2.2% of the population.     

Anterior maxillary supernumerary teeth: A clinical and radiographic study

Clinical records and radiographs of 90 patients with 113 anterior maxillary supernumerary teeth (mesiodens) have been evaluated. Although uncommon, mesiodentes are the most frequent supernumerary teeth and may disturb the eruption and/or position of the adjacent permanent incisors. Clinical and radiographic examination may disclose the number, direction and location of mesiodentes and their effects on neighbouring teeth. In the present study the majority of the supernumerary teeth lay palatal to the central incisors. Complete or partial eruption of a mesiodens was rare, hence the importance of radiographs to locate supernumerary teeth in the premaxilla. Pathological findings included the formation of dentigerous cysts in three patients and complete ossification of the pericoronal space with resorption of the crown of the mesiodentes in eight cases. Retention and malposition of the adjacent permanent incisors occurred in 39 and 24 cases, respectively.     

Three-dimensional space changes after premature loss of a maxillary primary first molar

Background.  A space maintainer is generally preferred when a primary first molar is lost before or during active eruption of the first permanent molars in order to prevent space loss. However, controversy prevails regarding the space loss after eruption of the permanent first molars.
Aim.  The purpose of this study was to examine spatial changes subsequent to premature loss of a maxillary primary first molar after the eruption of the permanent first molars.
Design.  Thirteen children, five girls and eight boys, expecting premature extraction of a maxillary primary first molar because of caries and/or failed pulp therapy, were selected. Spatial changes were investigated using a three-dimensional laser scanner by comparing the primary molar space, arch width, arch length, and arch perimeter before and after the extraction of a maxillary primary first molar. Also, the inclination and angulation changes in the maxillary primary canines, primary second molars, and permanent first molars adjacent to the extraction site were investigated before and after the extraction of the maxillary primary first molar in order to examine the source of space loss.
Results.  There was no statistically significant space loss on the extraction side compared to the control side ( P  = 0.33). No consistent findings were seen on the inclination and angulation changes on the extraction side.
Conclusions.  The premature loss of a maxillary primary first molar, in cases with class I molar relationship, has limited influence on the space in permanent dentition.     

Mesiodens--diagnosis and management of a common supernumerary tooth

Mesiodentes are the most common supernumerary teeth, occurring in 0.15% to 1.9% of the population. Given this high frequency, the general dentist should be knowledgeable about the signs and symptoms of mesiodentes and appropriate treatment. The cause of mesiodentes is not fully understood, although proliferation of the dental lamina and genetic factors have been implicated. Mesiodentes can cause delayed or ectopic eruption of the permanent incisors, which can further alter occlusion and appearance. It is therefore important for the clinician to diagnose a mesiodens early in development to allow for optimal yet minimal treatment. Treatment options may include surgical extraction of the mesiodens. If the permanent teeth do not erupt in a reasonable period after the extraction, surgical exposure and orthodontic treatment may be required to ensure eruption and proper alignment of the teeth. In some instances, fixed orthodontic therapy is also required to create sufficient arch space before eruption and alignment of the incisor(s). Early diagnosis allows the most appropriate treatment, often reducing the extent of surgery, orthodontic treatment and possible complications. This paper outlines the causes and modes of presentation of mesiodentes, and presents guidelines for diagnosis and management of nonsyndromic mesiodentes.     

Bilateral mesiodentes of identical twins--a case report

A pair of identical 10-year-old Chinese twins with bilateral mesiodentes of opposite orientation are presented. Three mesiodentes were conical and impacted, while the other one had erupted and was incisiform in shape. All roots of the mesiodentes were completely formed. Intrapair twin comparison showed a high degree of genetically determined concordance, with minor differences subject to environmental influences. The prevalence of mesiodens and rate of monozygotic twins in various ethnic groups are reviewed. Mirror image traits and verification of monozygocity in identical twins are also discussed.     

Retention of permanent incisors by mesiodens: a family affair

The term mesiodens refers to a supernumerary tooth that is present in the midline of the maxilla between the two central incisors. One or two mesiodentes may be present. We present a rare case of two sisters, in both of whom a pair of mesiodentes caused the retention of permanent incisors. They were referred to our hospital with asymptomatic delayed eruption of upper incisors. This article is written to point out genetic factors as the possible origin of supernumerary teeth.     

Mesiodentes in twins: a case report and a review of the literature

This report describes 7-year-old Afro-Caribbean monozygotic twin boys who both presented with bilateral unerupted mesiodentes palatal to the central incisors. There have been two previous similar reports. From this case and previous reports it was concluded that mesiodentes in monozygotic twins are likely to be concordant with respect to the number of supernumerary teeth. Unilateral mesiodens usually have been mirror imaged in each twin. Minor discordance between monozygotic twins is common with respect to the shape (conical, incisiform or tuberculate) and orientation (inverted or normal) of individual mesiodens within and between each twin.     

Factors affecting spontaneous eruption of impacted mandibular first molars after surgical exposure

Objectives

The purpose of this study was to investigate factors, such as the status of impaction, root developmental stage, depth of impaction, tooth angulation and eruption space, which can influence the spontaneous eruption of impacted mandibular first molars after surgical exposure.

Location, complications and treatment of mesiodentes--a retrospective study in children

Out of approximately 11 500 children, who had been referred to the Department of Paediatric Dentistry at the Institute for Postgraduate Education,J?nk?ping, Sweden, 97 individuals had a total of 123 mesiodentes. Their dental records and radiographs were analysed in order to study the clinical and radiographic features of the mesiodentes, to record the complications caused by them and to evaluate different forms of treatment. In the present study, the predominant location of the mesiodentes was palatally with 39 per cent in an inverted position. Arrest of the permanent incisors eruption, midline diastema and displacement or rotation of the incisors, were the most common complications found. On the contrary, no follicular cysts or resorption of either the mesiodens or the adjacent teeth were found. Fourty-three out of the 97 individuals were radiographically followed and no pathological findings were recorded. This study shows that the risk of complications caused by the mesiodentes seems to be very low and therefore a more restrictive attitude towards their surgical removal can be recommended.     

Mesiodens in primary, mixed and permanent dentitions: a clinical and radiographic study

The term mesiodens refers to a supernumerary tooth located between the maxillary central incisors. The aim of the study was to investigate the characteristics of mesiodens among children in Turkey. The study population involved 24 children who attended the Department of Pediatric Dentistry, Ege University for dental problems. The characteristics of mesiodens were obtained from clinical and radiographic examinations. Results showed that twenty-four patients had thirty-four mesiodens for an average of 1.42 mesiodens per person. Males were affected approximately 3 times more frequently in comparison with females. Forty-two percent of the patients had bilateral mesiodens. All of the mesiodens were conical in shape and 91% were in the downward position. The age and sex distribution, location, direction, eruption of mesiodens and effects on permanent maxillary incisors were also presented in this study. It could be concluded that, delayed, ectopic or asymmetric eruption of the central incisors should alert the clinician to the possibility of a mesiodens.     

Histological and chemical analyses of mesiodens development and mineralization

ObjectiveThis study aimed to compare the developmental timing and mineralization quality of mesiodentes, i.e., supernumerary teeth located mainly in the midline of the maxilla between the central incisors, with the developmental timing and mineralization quality of permanent and primary central incisors.DesignSixteen mesiodentes, nine permanent and seven primary central incisors were collected. The location of the neonatal line was determined using a light microscope at 10× or 20× enlargements. Chemical composition of the enamel at two locations was analyzed using energy dispersive X-ray spectrometer.ResultsNeonatal lines were observed in eight out of 16 mesiodentes, in all primary central incisors and in none of the permanent central incisors. Chemical analyses showed that mesiodentes mineralization was impaired, resulting in higher amount of organic ions and reduced inorganic ions. Discriminant analysis showed minimal overlap of mesiodentes with either primary or permanent centrals.ConclusionsMesiodentes development begins before birth in 50% of the cases but later than the primary centrals. Mineralization of mesiodens is impaired with less mineral content and higher organic content. The results showed that mesiodentes are a special group of teeth with defective morpho-differentiation and mineralization, with little similarity to primary or permanent central incisors.     

磨牙倾斜角度和萌出间隙对第三磨牙萌出的影响

目的研究影响第三磨牙阻生或萌出的一些客观因素。方法选择86例(男37例,女49例)平均年龄25.4岁,上下颌第三磨牙均存在的患者,将其分为萌出组和阻生组,利用曲面断层片对患者上下颌第三磨牙的近中倾斜角、牙冠近远中径、磨牙后间隙、磨牙后间隙和牙冠近远中径的比值进行测量分析。结果上颌萌出组萌出间隙较阻生组大1.95mm,第二磨牙和第三磨牙长轴交角相差12.53°,萌出组第三磨牙近远中径比阻生组小0.69mm,有统计学差异。下颌萌出组萌出间隙L-ES(R)较阻生组平均值大3.33mm;第三磨牙与牙合平面交角阻生组较萌出组大32.48°;萌出组与阻生组的磨牙后间隙/牙冠近远中径平均值分别为1.05、0.85,3项指标差异均有显著性(P<0.01)。下颌第三磨牙近远中径相差0.3mm,无统计学意义。结论第三磨牙萌出受萌出间隙和磨牙间交角的影响,对于上颌第三磨牙,磨牙交角影响更大,对于下颌第三磨牙无足够的间隙萌出,是导致下颌第三磨牙阻生的重要原因。     

早期拔除上颌正中多生牙与中切牙间隙之间关系的临床研究

目的探讨上颌正中多生牙与中切牙间隙的关系及早期拔除正中多生牙对于过大的中切牙间隙的意义。方法对120例上颌正中多生牙患者进行X线检查,是否造成中切牙间隙进行统计。并对105例有中切牙间隙患者拔除多生牙后进行2年的随访,观察间隙关闭效果。结果上颌正中多生牙可造成儿童中切牙间隙占87.50%;在侧切牙萌出前拔除多生牙间隙自行关闭程度明显优于侧切牙萌出后拔除,差异有统计学意义(P<0.01)。结论上颌正中多生牙(已萌出及埋伏)可造成宽大的中切牙间隙,早期拔除上颌正中多生牙对儿童中切牙宽大的间隙的调整有重要意义。     

Interalar Distance to Estimate the Combined Width of the Six Maxillary Anterior Teeth in Oral Rehabilitation Treatment

Statement of the Problem:  The face's architecture of dentate subjects has been studied to find a reliable guide for the selection of artificial anterior teeth. However, there is no consensus of data regarding a reference to estimate the width of artificial teeth.
Purpose:  The purpose of this study was to analyze whether there is a consistent relationship between the interalar distance (IAD) and the combined mesiodistal width of the six maxillary anterior teeth.
Methods:  Standardized digital photographs of 81 dentate Brazilian subjects were included in the sample. They were 37 men and 44 women (age 17 to 33). Through image processing software, the IAD and the distance between the tips of the maxillary canines were measured when viewed from the frontal aspect. Accurate casts were made to quantify the distance between the distal surfaces of the maxillary canines on a curve, by use of a flexible millimeter ruler. Nonparametric statistics were performed to analyze the results ( p  < 0.05).
Results:  The IAD when compared with the width of the six maxillary anterior teeth, on a straight line and on a curve, presented a ratio of 0.914 and of 1.305, respectively. The Wilcoxon test showed no significant difference between the calculated width values and the mesiodistal width measured on a curve and on a straight line ( p  = 0.986).
Conclusion:  The IAD, when increased by 31% of its value, can suggest the circumferential distance of the six maxillary anterior teeth.

CLINICAL SIGNIFICANCE

The width of the nose, when measured in digital photographs, can be utilized as a reliable guide for the selection of the maxillary anterior teeth width. It can improve the esthetic result of the oral rehabilitation treatment for the edentulous patient by offering a natural dentofacial relation.     

Variables affecting endodontic recall

Aim  To determine the recall rate in an endodontic practice and to evaluate specified variables as to their effect on the rate of patients returning for recall.
Methodology  The records of 7105 patients treated by one endodontist between 1975 and 1998 were reviewed. Recorded variables included chart number, patient gender and age, treated tooth number, pulp status, presence of spontaneous pain at initial visit, history of trauma to treated tooth, previous root canal treatment in the treated tooth, and presence of endodontic recall.
Results  The recall rate was 49% for the 5641 patients who completed endodontic treatment. Odds ratio analysis showed that females returned for recall at a rate that was significantly higher than males (52% vs. 44%). Odds ratio and chi square analysis revealed that a diagnosis of pulp necrosis or previous root filling resulted in a higher than expected recall rate while a diagnosis of irreversible pulpitis resulted in a lower than expected recall rate ( p  < 0.001). Patients aged 6–40 years of age returned at a lower rate than expected and those aged 41–80 returned at a higher rate than expected ( p  < 0.001). There was no significant difference in recall rate for patients reporting spontaneous pain or history of trauma with the treated tooth. The type of treated tooth had no effect on patient recall rate.
Conclusions  Forty-nine per cent of patients returned for recall after a minimum of 6 months with patient age, patient gender and pulp status affecting the rate of recall significantly.     

Mandibular third molar space in different antero-posterior skeletal patterns

Retromolar space has long been identified as a major factor in the aetiology of mandibular third molar impaction. The aims of this study were to compare mandibular third molar space between the different antero-posterior (A-P) skeletal patterns, between erupted and impacted third molars in the different A-P skeletal patterns, and to report on the status of third molar eruption/impaction among the studied subjects. A total of 432 mandibular third molars in 270 subjects (132 females and 138 males) were investigated from dental pantomograms (DPTs) and lateral cephalograms (LC). The average age for the total sample was 20.80 ± 2.03 years. The subjects were divided into three groups according to their ANB angle as follows: skeletal Class I (144 third molars in 90 subjects), skeletal Class II (145 third molars in 95 subjects), and skeletal Class III (143 third molars in 85 subjects). Each group was subdivided into impacted and erupted subgroups. DPT and LC were traced and the following variables were measured: retromolar space width, third molar width and angulation, β angle, second molar angulation, mandibular length, and gonial angle. Independent t-test, analysis of variance, and chi-square test were used for statistical analysis. Retromolar space width in the Class III subjects was smaller than in the Class I subjects (P?相似文献   

Necrotic pulp tissue dissolution by passive ultrasonic irrigation in simulated accessory canals: impact of canal location and angulation

Aim  To evaluate whether passive ultrasonic irrigation (PUI) of 2.5% NaOCl would dissolve necrotic pulp tissue from simulated accessory root canals (SACs) better than passive placement of the irrigant, when temperature was equilibrated between the two treatments.
Methodology  Transparent root canal models ( n  = 6) were made from epoxy resin. SACs of 0.2 mm diameter were placed at defined angles and positions in the mid-canal and apical area. SACs were filled with necrotic bovine pulp tissue. PUI was performed five times for 1 min each with irrigant replenishment after every minute. Main canal temperature was measured after each minute, and a digital photograph was taken. In control experiments, mock treatments were performed with the same set-up without activation of the file using heated NaOCl to mimic the temperature created by PUI. Experiments were repeated five times. Digital photographs were analysed for the distance of dissolved tissue into the SACs in mm. Overall comparison (sum of dissolved tissue from all five accessory canals) between treatments was performed using paired t -test. Differences between SAC angulation and position after PUI were investigated using anova /Bonferroni (alpha < 0.05).
Results  Passive ultrasonic irrigation caused a rise in irrigant temperature in the main canal to 53.5 ± 2.7 °C after the fifth minute. PUI dissolved a total of 6.4 ± 2.1 mm, mock treatment controlled for heat: 1.4 ± 0.6 mm ( P  <   0.05). No significant influence of SAC position or angulation was found.
Conclusions  Passive ultrasonic irrigation promotes positive tissue-dissolving effects beyond a rise in irrigant temperature.     

Mesiodens as a risk factor in treatment of trauma cases

Abstract –  The presence of mesiodens often results in complications including retention of primary teeth and delayed eruption of permanent teeth, closure of eruption path, rotations, retention, root resorption, pulp necrosis, and diastema as well as nasal eruption and formation of dentigerous and primordial cysts. Less common complications involving the permanent incisors include dilaceration of the developing roots and loss of tooth vitality. Therefore, early diagnosis of mesiodens has particular importance in terms of preventing such complications. However, with respect to surgical removal of mesiodens, ideal timing of intervention – immediate or delayed intervention – remains to be a highly controversial issue. While predisposing factors of dental trauma such as open bite, increasing overjet with protrusion of upper incisors, and insufficient lip closure have been well documented in the literature, there is limited evidence indicating mesiodens as a risk factor in trauma. In this report of two cases, it is aimed to emphasize mesiodens as a risk factor in the treatment of dental trauma besides its effect on prognosis.     

Radiographic evaluation of mandibular third molar eruption space.

OBJECTIVE: The purpose of this study was to investigate variables in third molar and arch dimensions among subjects with impacted and erupted mandibular third molars. STUDY DESIGN: Standardized panoramic radiographs were taken for 134 subjects (60 males and 74 females with 213 third molars) with an average age of 19.8 years. For the impacted group, only those who had mesioangular inclination of the third molars were recorded. The radiographic features studied were angulation of tooth, level of eruption, development of root, mesiodistal crown width, retromolar space, and gonial angle. RESULTS: Third molar angulation in the impacted group (69 subjects with 101 third molars) averaged 16.28 degrees (SD +/- 11.88 degrees), with no significant gender differences. The retromolar space was significantly smaller in the impacted group than in the erupted group (P < .001). This space was also the only significant variable (P < .05) associated with lateral asymmetry in the eruption/impaction status of third molars. In the impacted group, 83% of subjects had third molar space/crown width ratios less than 1, whereas in the erupted group 69% had ratios of at least 1. The average space/crown width ratios in the impacted and erupted groups were 0.78 and 1.06, respectively (P < .001). The impacted and erupted groups did not differ significantly with respect to mesiodistal crown width and gonial angle. Approximately 76% of impacted third molars had complete root formation, 20% had two thirds root formation, and only 4% displayed one third root formation. Of the impacted third molars, 66% were partially erupted and the rest were unerupted. There was a strong positive relationship between frequency of third molar impaction and degree of angulation (P < .001), but the former was inversely associated with retromolar space (P < .001). CONCLUSIONS: The most significant variable associated with third molar impaction is inadequate space. The vast majority of impacted third molars had space/crown width ratios of less than 1.     

C2Management of a patient exhibiting concomitant supernumerary teeth and hypodontia

Presenting problem:  A 14 year old male patient with delayed eruption of all permanent teeth with the exception of maxillary first permanent molars was referred to our clinic. The clinical examination of the patient showed no signs of abnormality. Mental and physical development was normal for his age and there were no signs or symptoms supporting the presence of syndromes related to eruption problems. Blood tests were within normal limits and there was no history of such a problem in the family. Radiological examination showed that all permanent first molars were present but only the maxillary first molars had erupted. In order to achieve spontaneous eruption of their permanent successors a general practitioner extracted the central primary mandibular incisors. However no eruption of the permanent successors was observed over a period of two years.
Clinical management:  A decision was made to surgically expose the crowns of the permanent central incisors in the lower jaw in order to promote spontaneous eruption. A year after the operation these teeth together with the mandibular third molars were partially erupted. No other teeth had erupted at this stage.
Discussion:  A case of delayed eruption of all permanent teeth is very rare, especially when it is not related to any known syndrome. The pathogenesis is a diagnostic riddle and the treatment demands a very careful approach.