Mandibular Second Molars Research Articles

Management of Unilaterally Impacted Permanent Mandibular First, Second and Third Molars

This case report describes the treatment of a teenage patient with simultaneous impaction of all three right mandibular permanent molars. The impacted first and second mandibular molars were surgically exposed and orthodontically erupted into good alignment and occlusion while the impacted third molar in the same quadrant was extracted. The unique clinical presentation, various treatment alternatives, the decision making process in finalizing the treatment plan and its clinical implementation are discussed.

External Root Resorption and Caries of Mandibular Second Molar in Association with Third Molar Impaction Status

Impaction status of a mandibular third molar (M3) leads to some pathological conditions. Objective: Thisretrospective study was conducted to compare the effect of erupted (e-M3) and impacted mandibular third molars(i-M3) on caries in the adjacent second molar and external root resorption (ERR). Methods: We used cone beamcomputed tomography (CBCT) images of 200 patients with a mean age of 28.19 ± 8.3 years who had an e-M3on one side of the mandible and an i-M3 on the other side of the mandible. All the images were evaluated for theexistence of caries and ERR. Results: Caries was detected in 32.5% of cases of i-M3 and in 21% of cases of e-M3(p = 0.01). ERR was present in 18.5% of cases of i-M3 and no resorption was observed in cases of e-M3 (p = 0.00).Conclusions: Caries and ERR in cases of i-M3 can be reliably identified via CBCT scan. Among patients withcaries in the i-M3 group, the degree of caries was significantly lower on the other side of the mandible. Instead ofprophylactic removal of e-M3, periodic clinical and radiologic examinations are advised.

Prevalencia de terceros molares mandibulares impactados y su asociación con caries distales en segundos molares mandibulares mediante tomografía computarizada de haz cónico.

This study evaluated the prevalence and eruption’s pattern of impacted mandibular third molars (IMTM) and the influence of their eruption status on the distal caries of mandibular second molars (MSM) using cone-beam computed tomography (CBCT). Material and methods: CBCT images taken for different purposes in private dental practices were analyzed retrospectively. Radiographic assessment included: prevalence of IMTM, degree of angulation, level of impaction and type of IMTM. Furthermore, the distance between the cement-enamel junctions (CEJ) of second and third molars and the occurrence of caries lesion on the distal surface of MSM was also evaluated. Data were analyzed by chi square test and logistic regression was used to find the association between distal caries of MSM and eruption status of IMTM. Results: Three hundred and eight CBCTs were screened, the prevalence of IMTM was 36.88% and their angulation degree were mostly less than 90º (mesioangular). Amongst those with impaction, 58 subjects (43%) had distal caries on MSM, 29.6% in females and 30.4% in the age group 19-27 years. Caries on the distal side of MSM were significantly associated with age, level and type of impaction, angulation degree and CEJ distances (p<0.05). Conclusions: The prevalence of IMTM is high (36.88%) and there are significant relationships between angulation degree, level and type of impaction, and CEJ distances with caries on the distal side of MSM.

Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients.

Cortical bone thickness, bone width, insertion depth, and proximity to nerves are important factors when planning and placing orthodontic miniscrews. The objective of this study was to anatomically assess the mandibular buccal shelf in a white patient population as the insertion site for orthodontic miniscrews by investigating these 4 variables. Measurements were made on cone-beam computed tomography scans of 30 white patients (18 girls, 12 boys; mean age, 14.5±2years). All measurements were taken adjacent to the distobuccal cusp of the first molar, and the mesiobuccal and distobuccal cusps of the secondmolar. Additionally, bone depth was measured at 2 height levels, 4 and 8mm from the cementoenamel junction. Stereolithographic models of patients were superimposed on the cone-beam computed tomography volumes to virtually create an outline of the soft tissue on the cone-beam computed tomography image to allow identification of the purchase point height (mucogingival junction). The inferior alveolar nerve was digitally traced. Miniscrews (1.6×10mm) were virtually placed at the buccal shelf, and their insertion depths and relationships to the nerve were assessed. Analysis of variance with post hoc analysis was used for data analysis. Insertion sites and measurement levels had significant impacts on both cortical bone thickness and bone width. Cortical bone thickness was typically greatest at the distobuccal cusp of the secondmolar. Bone width was also greatest at the distobuccal cusp of the secondmolar 8mm from the cementoenamel junction. The greatest insertion depth was found again at the distobuccal cusp to the secondmolar, whereas the miniscrews had the greatest proximity to the nerve at this site also. The distobuccal cusp level of the mandibular secondmolar is the most appropriate site for miniscrew insertion at the buccal shelf in white patients.

Occurrence of intermediate bifurcational ridges and attached cementicles on furcation area of Iraqi mandibular molars

Successful treatment of molar furcation defects remains a challenge in clinicalpractice. Knowledge of anatomic factors facilitates predictable management offurcation involvement lesions. Intermediate bifurcational ridge (IBRs) andcementicles are of those anatomical variations which considered as problems inprogression treatment of the disease.The present study was carried out to investigate the prevalence of IBRs andcementicles in Iraqi mandibular molars. The sample used in the study included 498extracted mandibular molars. The results revealed that the prevalence IBRs was306/498 teeth (61.44%), and that for the cementicles was 204/498 teeth (40.96%).The total sample was allocated into two groups:Group 1 included 313 molars (165 mandibular first molar and 148 mandibularsecond molar) , The teeth of group 1 were extracted because of caries andpulpal lesions, whileGroup 2 included 185 mandibular molars ( 98 first molar and 87 second molar).The reason of extraction of the teeth of group 2 was periodontal disease (differentdegrees of furcation involvement). For group 1 the results showed that 111/313(35.46%) of mandibular molars had attached cementicles in furcation area and185/313 (59.10%) were affected by IBRs. While in group 2 the percentage of bothanomalies was higher than that of group 1. In group 2 the results revealed that 93/185(50.27%) of the teeth had cementicles and 121/185 (65.4%) were recorded withIBRs.These results give an indication that the prevalence of cem. and IBRs highenough to be of clinical importance.

An extremely rare case of radiculous premolar coexisting with bilateral fourrooted mandibular second molars

We present a rare case of three-rooted left permanent maxillary first premolar (MFP) coexisting with bilateral four-rooted permanent mandibular second molars (MSM). These variants were found incidentally on cone beam computed tomography (CBCT) images. At best of our knowledge, this is the first report presenting these rare tooth root variants in one patient. Although this condition is uncommon the radiologists and clinicians should be aware because of its importance for the successful root canal treatment, future tooth extraction, apicectomy and other procedures. This report adds a new knowledge about tooth roots variants and illustrates the possibility of their coexistence in one patient.

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Third Molar and Their Relationship with Caries on the Distal Surface of Second Molar: A Meta-analysis.

The aim of this meta-analysis was to determine which characteristics of mandibular third molars (MTMs) are more often associated with an increase in the prevalence/incidence of caries on the distal surface of mandibular second molars (MSMs). Three electronic databases were analyzed: PubMed; OVID and the Virtual Health Library. Observational studies were included, and the risk of bias was assessed using The Newcastle-Ottawa Scale. The Comprehensive Meta-Analysis software program was used for meta-analysis. Fifteen studies were included in this systematic review, and five were included in the meta-analysis. The distal surface of MSMs were more likely to exhibit caries in the following scenarios: when MTMs were found in the A position, rather than the C position (OR: 3.45, 95% CI: 2.28-5.22, p<0.001); when the horizontal position was compared with the vertical (OR: 8.12, 95% CI: 3.75-17.58, p<0.001) and distoangular (OR: 9.75, 95% CI: 3.49 - 27.25, p<0.001) positions; and when the mesioangular position was compared with the vertical (OR: 7.25, 95% CI: 3.48-15.10, p<0.001) and distoangular (OR: 9.54, 95% CI: 3.47 - 26.21, p<0.001) positions. The results of this study suggest that the presence of MTMs increases the incidence of caries on the distal surface of MSMs. Furthermore, caries on the distal surface of MSMs is more commonly associated with position A and horizontal and mesioangular mandibular molars.

MOLAR CARIES;

Objectives: To identify risk factor of distal surface caries on mandibular secondmolar associated with partially erupted mandibular third molar. Setting: The study wasconducted in the Department of Oral and Maxillofacial Surgery, Liaquat University HospitalJamshoro/Hyderabad from April 2013 to September2013. Methodology: Total 273 patientsof either gender with age 16-45 years had partially impacted mandibular third molar, wereincluded. Diagnosis was made on clinical as well as periapical view and OPG examination.Distance from CEJ of mesial surface of third molar to CEJ of distal surface of second molarwas measured in millimeters. Results: Results about association of caries with other variablesshowed that significant association of caries was observed with gender, winter classification,Pell Gregory (ramus), and angulation with p&lt;0.01. The association of caries was also observedwith age and third molar site with p&lt;0.05. The association was not significant with Pell Gregory(occlusal) and distance with p&gt; 0.05. Conclusion: It was concluded with the results of thisstudy that there was an increased risk of developing dental caries in 2nd molar tooth at distalsurface with risk factor being partially erupted mandibular 3rd molar, mesioangular, class I, levelA, and angulation of more than 30 degrees.

English

Objectives: To identify risk factor of distal surface caries on mandibular secondmolar associated with partially erupted mandibular third molar. Setting: The study wasconducted in the Department of Oral and Maxillofacial Surgery, Liaquat University HospitalJamshoro/Hyderabad from April 2013 to September2013. Methodology: Total 273 patientsof either gender with age 16-45 years had partially impacted mandibular third molar, wereincluded. Diagnosis was made on clinical as well as periapical view and OPG examination.Distance from CEJ of mesial surface of third molar to CEJ of distal surface of second molarwas measured in millimeters. Results: Results about association of caries with other variablesshowed that significant association of caries was observed with gender, winter classification,Pell Gregory (ramus), and angulation with p&lt;0.01. The association of caries was also observedwith age and third molar site with p&lt;0.05. The association was not significant with Pell Gregory(occlusal) and distance with p&gt; 0.05. Conclusion: It was concluded with the results of thisstudy that there was an increased risk of developing dental caries in 2nd molar tooth at distalsurface with risk factor being partially erupted mandibular 3rd molar, mesioangular, class I, levelA, and angulation of more than 30 degrees.

Surgical Uprighting Is a Successful Procedure for Management of Impacted Mandibular Second Molars

Impacted mandibular secondmolars can cause caries and root resorption on adjacent molars and can lengthen orthodontic treatment. Surgical uprighting is one management option. The purposes of this study were to 1) evaluate radiographic outcomes for surgical uprighting of impacted mandibular secondmolars and 2) propose an etiology for impaction. This was a retrospective cohort study of patients who had surgical uprighting of mandibular secondmolars and had preoperative and at least 12-month postoperative panoramic images and an age- and gender-matched control group of patients undergoing routine orthodontic treatment. Predictor variables included age, gender, impaction type, preoperative angle of impaction, preoperative periodontal bone level distal to an adjacent first molar, posterior eruption space, pathology, and concomitant extraction of the adjacent third molar. Outcome variables were change in impaction type, postoperative periodontal bone levels around the first and secondmolars, postoperative tooth angle and posterior eruption space, periapical radiolucency, pulpal obliteration, root resorption, and need for extraction. Descriptive statistics were calculated. The sample and control groups each had 16 patients. The mean ages at the first radiographs were 13±1.1 and 13.19±0.61years for the treatment and control groups, respectively, and the mean follow-up radiographs were obtained 2.4±1.4 and 2.3±0.82years later. No preoperative images showed pathologic lesions obstructing eruption. Postoperatively, all uprighted molars were Pell and Gregory type IA. The mean change in the angles of the uprighted teeth was 23.5±16.1° (P<.001). The mean distal bone levels of the adjacent first molar were 3.41±1.52mm preoperatively and 1.45±0.54mm postoperatively (improvement, 42.5%; P<.001). The preoperative posterior eruption space was 53.6% longer in the control than in the treatment group (P<.001), and the increase in this distance postoperatively was greater for the treatment group than for the control group (P<.001). Pulpal obliteration (n=6; 31.5%), periapical radiolucency (n=2; 10.5%), and root resorption (n=1; 5.3%) were seen on postoperative radiographs. There were 2 failures (10.5%). Surgical uprighting of mandibular secondmolars is a useful procedure with a low failure rate. Insufficient space for eruption is the likely primary etiology for impaction.

Evaluation of dental and skeletal maturity using digital panoramic radiographs and digital cephalograms

Background: Assessing the maturational status and pubertal growth spurt of a patient has considerable influence on diagnosis, treatment planning, and the outcome of orthodontic treatment. Objectives: To assess the usefulness of panoramic radiographs as a tool to estimate the growth and to ascertain the importance of tooth calcification stages as an indicator of maturity by using digital panoramic radiographs. Methods: We compared the dental maturity assessed by calcification of mandibular canine, first premolar, second premolar, and second molars using digital panoramic radiographs and skeletal maturity assessed by cervical vertebral maturation stages using lateral cephalograms and hand-wrist radiographs. Skeletal maturity was assessed using a cervical vertebrae maturation technique; hand-wrist maturity was evaluated using Fishman skeletal maturity indicators. Dental maturity was estimated according to guidelines of Demirjian. Spearman rank–order correlation coefficients were used to determine the correlation between tooth calcification stages and skeletal maturity assessed on panoramic radiographs, lateral cephalograms, and hand-wrist radiographs of 60 patient participants, including 45 boys and 15 girls. Results: The panoramic radiograph is a reliable tool with which to estimate of growth and development of boys. Conclusion: The relationship between tooth calcification stages and the skeletal maturity indicators in boys allows clinicians to identify the stage of the pubertal growth from panoramic radiographs. It is appropriate to put these skeletal and dental maturation relationships into daily orthodontic diagnostic practice.

Lingual Nerve Measurements in Cadaveric Dissections: Clinical Applications

Lingual nerve (LN) injury is quite prevalent despite its long-known anatomic course. The purpose of this study was to accurately predict the LN pathway by identifying and measuring close anatomic landmarks; these measurements should help lessen the incidence of LN injury. LN dissection was carried out on 15 halved cadaver skulls (total, 28 specimens). On average, the LN position was approximately 7mm below the alveolar crest at the distal end of the mandibular secondmolar, 5.5mm anterior to the lingula, and 14.6mm distal to the alveolar crest at the mandibular secondmolar. From the base of the skull, the LN traveled 5mm anteriorly to the inferior alveolar nerve and inferiorly to the posterior attachment of the mylohyoid muscle (approximately 1.5cm distal to the mandibular secondmolar), where it turned anteromedially and traveled 7mm inferiorly to the alveolar crest at the mandibular secondmolar. Given the multiple procedures by dental practitioners and maxillofacial surgeons, the LN is at high risk for injury. This study validates the proximity of the LN to anatomic structures commonly encountered during head and neck procedures.

C-shaped single canaled mandibular second molar: A rare case report

This case report presents a rare root canal system in a mandibular second molar tooth, a single root with a single canal. C-shaped canals with varying configuration are commonly observed in single-rooted mandibular second molars. The access cavity displayed only one round/oval canal orifice which is very rare. The knowledge of dental anatomy is an essential tool for the success of endodontic treatment. The early recognition of these configurations facilitates cleaning, shaping, and obturation of the root canal system. Therefore, a clinician thus requires to have adequate knowledge about root morphology and its variation. Thorough knowledge of the root canal anatomy is necessary to perform a successful endodontic treatment.

Pattern of mandibular third molar impaction and its association to caries in mandibular second molar: A clinical variant.

Caries in second molar is common and prophylactic removal of the impacted teeth may be considered appropriate. Caries detection and restoration can be difficult and a restored second molar can undergo recurrent caries if the third molar is not removed prophylactically. In this study, the clinical findings related to impaction and its association with angular position and depth of impacted third molar were evaluated. A retrospective descriptive study was carried out among the patients visiting the outpatient, department of Dentistry, RIMS, Ranchi. The clinical examination, periapical radiographs and Pre-op OPG were taken. Teeth positions were analyzed by Pell and Gregory and Winter classification. The angulation and depth of mandibular third molar impaction and caries in the second molar with the eruption status of the mandibular third molar was determined. A total of 200 patients were included in the study between age group 17-45 years. Majority of the Patients reported to the hospital with complaints of decayed tooth (66%) and pain (59%). The most common third molar impaction was mesioangular followed by distoangular. A statistically highly significant difference (P = 0.001) was obtained with the presence of caries in second molar adjacent to mesioangular third molar in class I and level B. According to this study, pattern of mandibular third molar impaction is in association to caries in mandibular second molar. More future studies are needed. In addition, the results of the present study can be used to screen and inform the patients about the possibility of caries in relation to third molar mandibular impaction.

Middle Mesial Canal in Mandibular Second Molar

Middle Mesial Canal in Mandibular Second Molar

Management of periodontal infection leading to mandibular extra-oral sinus in 13-year-old male

Cutaneous sinus tract of odontogenic origin is the most common among the various types of sinus tracts which are formed on the face and neck. Cutaneous sinus tracts may develop from local chronic osteomyelitis. Although the causative factor is generally periapical infection of odontontogenic origin, they are rarely of periodontal origin. This paper describes a case of the mandibular extraoral sinus of periodontal origin in 13yearold boy, in whom the condition arose following periodontal infection in relation to permanent mandibular left second molar with probing pocket depth 10 mm distobuccally. The source of infection was associated with developing the third molar which had no visible communication with the oral cavity. The case was managed by removal of the source of infection with periodontal treatment.

Evaluation of Mandibular Third Molar Position by Using Space-Width Ratio Method

Background: The prediction of changes in the mandibular third molar position and eruption is an important clinical concern because third molar retention may be beneficial for orthodontic anchorage. The aims of this study were to assess the mandibular third molar position by using medical CT scan and lateral reconstructed radiograph and evaluate gender differences. Materials and Methods: The sample of present study consisted of 39 patients (18 males and 21 females) with age range 11-15 years who were attending at Al-Suwayra General Hospital/ the Computerized Tomography department. The distance from anterior edge of ramus to distal surface of permanent mandibular second molar and mesio-distal width of developing mandibular third molar were measured in both three dimensional volumetric and two dimensional CT derived lateral images. The statistical analyses included: means, standard deviations. Paired t-test was used to compare between the two methods and independent t-test was used in verifying the genders difference. Results: The results showed that there was high significant method difference between 3D CT and 2D image and gender differences were observed in values of linear measurements of present study, as males showed higher mean values than females. Conclusion: There is high accuracy of measurement on CT images, so C.T. scan is advisable during the diagnosis and treatment plan of orthodontic cases.

A Study of the Morphology of Deciduous Mandibular Second Molars

Objectives. Variability in tooth morphology plays a significant role in the achievable results of restorative treatment. The purpose of this study was to identify variations in morphology of deciduous mandibular second molars and to compare their crown sizes and shapes in order to provide a detailed description of the morphological characteristics of these teeth. Methods. The materials consisted of 142 (71 from boys and 71 from girls) dental stone casts of complete deciduous mandibular arches. Standardized photographs of the occlusal surfaces of the stone casts were obtained. The selected reference points on the photographs were digitized by an image analyzer, converted to an X-Y coordinate system, and input into a personal computer for data analysis. Eight linear and eight angular measurements were taken for each deciduous mandibular second molar. The deciduous mandibular second molars were classified as five-, six-, seven- and eight-cusp groups. Results. Thirty-six percent of the deciduous mandibular second molars were comprised of five cusps, 52% were comprised of six cusps, 11% were comprised of seven cusps, and 1% was comprised of eight cusps. The eight-cusp group had three accessory cusps (ML, MR, and D). The six-cusp group was subdivided into 6ML, 6MB, and 6D types, while the seven-cusp group was subdivided into 7MLD and 7MLMB types according to the positions of the accessory cusp. Most teeth in the six-cusp group were of the 6ML type. Measurements of Ll, L2, L5, and A6 were significantly smalle; in the five-cusp group than in the 6ML type in boys; however, no significant difference was observed in girls. Conclusions. The crown shape and size of deciduous mandibular second molars might be influenced by the existence of an accessory cusp in Taiwanese boys.

Effect of Eruption Status of the Mandibular Third Molar on Distal Caries in the Adjacent Second Molar

To analyze the effect of the eruption status of the mandibular third molar (MTM) on distal caries in the mandibular secondmolar (MSM) by cone-beam computed tomography (CBCT). Five hundred CBCT images of MTMs from 469 patients were evaluated. Presence of distal caries in MSMs, impaction depths and angulations of MTMs, cementoenamel junction (CEJ) distances between distal MSMs and mesial MTMs, presence of pericoronitis in MTMs, and patient characteristics (age and gender) were assessed. Data were analyzed by χ(2) test, univariate and multivariate logistic regression analyses, and Spearman correlation analysis. Descriptive and bivariate statistics were computed and the P value was set at .05. The overall prevalence of distal caries in the MSM was 52.0%. According to the classification of Pell and Gregory, position A was the impaction depth at which most distal caries in MSMs were present (P= .036). For angulation of the MTM, when mesial angulations were 43° to 73°, MSMs developed more distal caries (P < .0001). For the CEJ distance between the distal MSM and the mesial MTM, when distances ranged from 6 to 15mm, distal caries in MSMs occurred more frequently (6 to 8mm, P < .0001; 8 to 15mm, P= .037). Furthermore, there was a linear correlation between angulation of the MTM and the CEJ distance between the distal MSM and the mesial MTM (P < .0001). Impaction depth and angulation of the MTM are associated with distal caries in the MSM. Angulation of the MTM is more stable and reliable than the CEJ distance between the distal MSM and the mesial MTM for the estimation of risk factors related to the MTM.