Impacted Third Molars Research Articles

Distal surface caries in the mandibular second molar in the presence of a partially erupted/impacted third molar

Distal surface caries in the mandibular second molar is a common outcome of impaction of the adjacent third molar. To determine the prevalence of this type of caries in the Netherlands, 250 radiographs were evaluated. The prevalence among the research population was 26%. Risk factors for developing distal surface caries in the mandibular second molar were partially erupted/impacted third molars with a mesioangular or horizontal angulation, an LD loss of ≥ 2mm and an increased modified DMFT score. The relation between the point of contact of the third molar and the adjacent mandibular second molar, on the one hand, and, on the other, the cemento-enamel junction of the mandibular second molar and the prevalence of distal surface caries almost reached statistical significance (p = 0.052). The relatively low prevalence of distal surface caries in the Netherlands is probably related to the current clinical guidelines recommending early extraction of partially erupted/impacted third molars, particularly in cases of third molars with a mesioangular or horizontal angulation.

A prospective randomized study on the efficacy of real-time dynamic navigation in deep horizontal mandibular third molar extractions

PurposeThis study aimed to evaluate the clinical efficacy of applying real-time dynamic navigation (RDN) in the extraction of deep horizontal mandibular impacted third molars, hypothesizing that RDN reduces surgical time and minimizes the risk of injury to adjacent anatomical structures.MethodsA prospective study was conducted on 160 patients aged between 18 and 37 years with deep horizontal impaction of the mandibular third molar. The participants were randomly assigned to either the experimental group (receiving RDN-assisted extractions) or the control group (undergoing traditional extraction methods). Preoperative planning utilized cone beam computed tomography (CBCT) and Mimics software for the accurate localization and segmentation of impacted teeth. Parametric data were analysed via an independent t test for intergroup comparisons, and significance was set to p < 0.05.ResultsIn the experimental group, an average of 11 ± 1 min was required for preoperative planning via RDN, which was not required in the control group. The setup of the navigation system took an average of 4 ± 1 min in the experimental group and 0 min in the control group. The experimental group demonstrated a significantly shorter average surgical time (22 ± 3 min) than did the control group (36 ± 3 min). The differences in the preoperative design time, surgical time, and complication rates between the two groups were statistically significant (p = 0.005). Additionally, the RDN group reported no complications related to adjacent tooth damage or nerve injury.ConclusionThe precision, safety, real-time guidance of RDN supports its use in complicated dental extractions, which would introduce a new era of oral and maxillofacial surgery.Graphical

Prevalence and pattern of third molars impaction in a large Yemeni sample: a retrospective study.

The prevalence of teeth impaction varies substantially between different populations, and the impaction of third molars is the most commonly recorded. This study aimed to explore the prevalence and pattern of the third molars impactions among Yemeni population. This was a retrospective radiographic study conducted in Yemen between 2022 and 2023. The digital panoramic radiographs were collected from two major X-ray centers in Yemen. The angular position and depth of the impacted third molars were assessed according to the classifications of Winter and of Pell and Gregory, respectively. All radiographs were evaluated twice by one investigator in a two-week interval, and Kappa test was used for intra-rater reliability. Gender-wise differences, differences between both sides, and differences between maxilla and mandible were analyzed using Chi-squared tes with odds ratio (OR) for the risk of impaction. A P-value < 0.05 was considered significant. Panoramic radiographs of 6338 individuals were included. Their mean age was 35.1 ± 13.3 years andand 63.9% were females. A total of 25,352 sites (quadrants) were screened for the presence of thirds molars. Among which, 14,003 third molars (55.3%) were present in one or more sites. There were 1440 individuals (23%) with a total of 2828 impacted third molars (20% of the existing third molars). Females were less likely to have third molar impaction (OR = 0.46, CI95% = 0.4-0.52). Impaction of the mandibular third molars was significantly more frequent than the maxillary ones (OR = 1.15, CI95% = 1.04-1.26; P = 0.005). Horizontal and mesioangular impactions were statistically more frequent in the lower molars compared to the upper ones (P < 0.001 each). Contrastingly, vertical (P = 0.015), distoangular, and other impactions (P < 0.001 each)were statistically more frequent in the maxilla. Levels A and B were more frequent in the lower third molars, while level C was predominating in the upper molars (P < 0.001 each). The prevalence of third molars impaction is more frequent in males and mandibular arch. The angulation and level of impaction seem to be more complicated in the maxillary arch.

Level of knowledge of undergraduate students in surabaya city about third molar impaction and management

Background: Dental and oral health issues in Indonesia are among the most, with a prevalence of 25.9% and caries as the main problem reaching 45.3% in 2018. Undergraduate students experience impaction the most because third molars grow at the age of 17-21 years and the roots are complete at 18-25 years. Odontectomy is needed to treat impacted teeth, which if left untreated can cause serious complications such as pain, swelling, caries, pericoronitis, and tumors. Objective: To create a valid and reliable questionnaire about the knowledge of undergraduate students in Surabaya regarding impaction of third molars and its management. Methods: This study is a questionnaire study with a descriptive observational approach with cross-sectional study. Result: The validity and reliability test shows that all 15 questions have r values exceeding 0.361, confirming their validity and reliability. Specifically, the r values for the questions range from 0.462 to 0.577. These results indicate that the questionnaire is effective for assessing the knowledge level of undergraduate students in Surabaya regarding third molar impaction and its management. Each question meets the necessary criteria, making the instrument a reliable tool for the intended evaluation. Conclusion: This research concludes that the questionnaire assessing the knowledge of Surabaya undergraduate students about third molar impaction is valid, as the calculated r value exceeds the r table value.

Comparison of the mandibular retromolar space in adults with different sagittal skeletal types and eruption patterns of the mandibular third-molar: a cone-beam computed tomography study

BackgroundThe mandibular retromolar space (RMS) has not been extensively studied in relation to various sagittal skeletal classes and patterns of third-molar eruption. The objective of this study was to test the null hypothesis that there is no difference in the mandibular RMS among normodivergent subjects with different skeletal classes and patterns of mandibular third-molar eruption, using cone-beam computed tomography (CBCT).MethodA total of 105 normodivergent patients (20–40 years) were included in this study. Participants were categorized into Class I, II and III groups based on ANB and further impacted and erupted groups based on the eruption patterns of the mandibular third molars. Measurements of the mandibular RMS were taken at four planes parallel to the occlusal plane, along the cusp line. Comparative analyses were conducted among the three sagittal groups and between the impacted and erupted groups.ResultsThe Class II group exhibited a statistically smaller RMS (P < 0.05). RMS was found to be larger in third-molar erupted group (P < 0.05). The rates of root contact and third-molar impaction was significantly higher in Class II group. (P < 0.05)ConclusionsThe null hypothesis was rejected. Patients with Skeletal Class II tend to have a smaller mandibular RMS and a higher prevalence of root contact and third-molar impaction. The presence of impacted mandibular third molars was correlated with a shorter RMS.Trial registrationRetrospectively registered.

Impact of Mandibular Third Molars on Mandibular Angle Fracture

Impact of Mandibular Third Molars on Mandibular Angle Fracture

Interdisciplinary treatment of a mutilated dentition with multiple missing teeth and horizontal impaction of a mandibular third molar using an orthodontic skeletal anchorage and dental implants-Case report.

This case report presents a female adult patient who exhibits poor oral hygiene, a mutilated dentition with multiple missing teeth, and skeletal asymmetry. Interdisciplinary treatment was necessary to maintain oral hygiene, treat caries, extract residual roots, and upright a horizontally impacted third molar using a miniplate. Additionally, orthodontic mini-implants were utilized as anchorage to improve sagittal relationship and space closing. Space management was completed with orthodontic treatment, followed by restoration of the multiple missing teeth with dental implants. Consequently, an esthetic smile and functional occlusion were achieved by interdisciplinary treatment using orthodontic skeletal anchorage devices and dental implants. Missing mandibular first molar spaces were closed with retraction of the anterior teeth and protraction of the mandibular second molars using orthodontic mini-implants. The mandibular right third molar, which should have erupted, was protracted with the second molar, while the horizontally impacted mandibular left third molar was uprighted using a miniplate and was protracted with an orthodontic mini-implant. The missing maxillary lateral incisors were replaced with the maxillary canines, and the maxillary canines were replaced with the maxillary first premolars. The missing maxillary right second premolar and first molar and left first and second molars were successfully restored with dental implants.

Are There Differences in the Causes and Complications of Mandibular Third Molar Extraction in Older Patients Compared to Younger Patients?

BackgroundAlthough most impacted third molars (ITM) are extracted in the teens and early 20s, some undergo extractions after their 40s. It is unclear whether the reasons for extraction, the degree of impaction, and complications differ in patients in an older age group compared with a younger age group. PurposeThe purpose of this study was to measure the association between age and 1) reason for extraction and 2) postoperative complications. Study design, setting, sampleThis was a retrospective cohort study of patients who had undergone surgical extraction of at least one mandibular ITM at a single institution. We excluded 1) age under 20 years, 2) follow-up period of less than 1 week, and 3) tooth extraction under general anesthesia. Predictor variableThe primary predictor variable was age, classified into 3 groups (20s:20-29; 30s:30-39; over 40s: 40 and greater). Outcome variableThe primary outcome variables were reason for extraction (prophylactic or symptomatic) and presence of complications. The secondary outcome variable was type of complication (post-operative infection, dry socket, neurosensory disturbance, presenting pain over 1 month, retained root requiring secondary treatment). CovariatesThe covariates were sex, laterality of ITM, and difficulty of extraction as measured by the difficulty index, a measure based on depth, orientation, and ramus relationship/space available, with a higher score indicating greater difficulty. AnalysesChi-square test was performed to analyze the association of categorical outcome variables and covariates. Level of statistical significance was set at P<0.05. ResultsOf a total of 831 eligible subjects, there were 555 (66.8%), 159 (19.1%), and 117 (14.1%) in 20s, 30s and over 40s age groups, respectively. The percentage of symptomatic extraction of ITM was significantly higher in the over 40 age group compared with the 20s group (92.3% vs. 69.4%, (p<0.001). Complication rate also significantly differed between over 40s group and the 20s group (7.7% vs. 1.8%, p<0.001). Difficulty index and indications for ITM extraction were significantly different between groups (p<0.001). ConclusionSymptoms, difficulty, and complications related to ITM increase at over 40 years of age. This should be taken into consideration during the joint clinical decision-making process with patients with ITM.

Comparison of perineural and systemic dexamethasone use in impacted third molar surgeries in terms of anesthesia duration and postoperative complaints: a controlled, randomized observational study

BackgroundSurgical extraction of impacted third molars (ITM) often leads to postoperative discomfort including pain, swelling, and limited function. Steroids like dexamethasone (DXN) are commonly used in oral surgery to manage pain and inflammation. Various administration routes for DXN exist, including intravenous (IV), perineural (PN), and oral applications, each with its advantages. Previous studies have shown that adding DXN to local anesthetics can prolong anesthesia duration and reduce postoperative sequelae. However, comparative studies on IV and PN applications with inferior alveolar nerve block (IANB) of DXN in ITM surgeries are limited.MethodsThis controlled, randomized observational study involved patients undergoing Class II position B ITM extraction. Patients were divided into three groups. IANB (1.8 ml of articaine hydrochloride + 1 ml of saline) was performed 1 h after IV-DXN (4 mg/ml DXN) was administered to the IV group. DXN along with IANB (1.8 ml of articaine hydrochloride + 1 ml of 4 mg/ml DXN) was applied to the PN group. Only IANB (1.8 ml of articaine hydrochloride + 1 ml of saline) was applied to the control group. Anesthesia duration was assessed as primary outcomes. Anesthesia duration was evaluated using a vitalometer from the molars. Secondary outcomes included postoperative pain and edema measured on the 1st, 3rd, and 7th days after surgery. Pain was evaluated postoperatively by using a visual analog scale. A p-value < 0.05 was considered statistically significant.ResultsThe study included 45 patients with similar demographic characteristics across groups. IV application significantly prolonged anesthesia duration compared to the control group. (p = 0.049) Both IV and PN administration of DXN reduced postoperative edema at 3rd (p = 0.048) and 7th day (p = 0.01). Post-procedure pain reduction was significant in the IV group (p = 0.011). On the other hand, it was observed that the pain did not decrease in the PN group at 3rd and 7th days compared to the control and IV groups.ConclusionsPN and IV DXN administration prolonged anesthesia duration and reduced postoperative edema in ITM surgeries. However, PN DXN administration was associated with increased postoperative pain compared to IV DXN and control groups. Further studies comparing different doses and administration routes of DXN are needed to determine optimal strategies for managing postoperative discomfort in ITM surgeries.Trial registrationThis study was conducted at Ahmet Keleşoğlu Faculty of Dentistry with the permission of Karamanoğlu Mehmetbey University Faculty of Medicine Ethics Committee (#04-2022/101). Trial registration is also available at clinicaltrail.gov. (NCT06318013, 26/05/2024)

Retrospective analysis of the effects of impacted third molar on hematologic patients undergoing hematopoietic stem cell transplantation

ObjectiveThis study aimed to investigate the incidence, treatment status, and impact position of impacted third molars (ITM) and their effects on patients undergoing hematopoietic stem cell transplantation (HSCT). MethodsA retrospective analysis was conducted on the medical records of 454 patients who underwent HSCT, out of which 188 patients had ITM. The presence of ITM and its association with transplant-related infections and complications were recorded and analyzed. ResultsPatients with ITM were significantly younger. The number of mandibular ITM was notably higher than maxillary ones, and the risk of pericoronitis in mandibular ITM was significantly higher than in maxillary ones. Out of 311 ITM in 188 patients, 25 were extracted before transplantation. The proportion of extraction and treatment for ITM with pericoronitis or caries was significantly higher than that for ITM without such problems. Moreover, patients with a history of pre-transplant pericoronitis had a significantly higher probability of developing tooth-related complications during transplantation, caused by pericoronitis in ITM compared to patients without a history of pericoronitis. ConclusionPre-transplant examination and treatment of ITM are essential, especially in cases with a history of pericoronitis. Oral intervention can significantly reduce the occurrence of tooth-related complications related to ITM during transplantation.

The Role of Dental Arch Dimensions and Impacted Third Molars on Mandibular Anterior Segment Crowding.

This study aimed to investigate the potential impact of arch dimensions and unerupted third molars on mandibular anterior segment crowding. This study included a total of 240 subjects with an average age of 18 years seeking orthodontic treatment. Panoramic radiographs, alginate impressions, and study models were taken for measurements. This study utilized the Ganss ratio to calculate the ratio of retromolar space to the width of the crown of the third molar, along with other measurements such as intercanine and intermolar widths, arch perimeter, and arch length to assess dental arch dimensions. We found that the Ganss ratio and angle B values on both the right and left sides were significantly different between the noncrowding and crowding groups, suggesting a potential role for third molars in mandibular anterior segment crowding. Additionally, there was an increase in angle A on both sides in the crowding group, indicating a more acute angle between the anterior teeth. This study also observed a reduction in the retromolar space on the third molars in the crowding group, further supporting the potential role of third molars in mandibular anterior segment crowding. The findings of our study provide substantial evidence to suggest that third molars may contribute to mandibular anterior segment crowding. These findings highlight the importance of carefully evaluating dental arch dimensions and the presence of third molars when assessing and treating mandibular anterior segment crowding.

The impact of maxillary non-impacted third molars on the distal alveolar bone of adjacent teeth using CBCT: a retrospective study.

The purpose of the study was to determine how the maxillary non-impacted third molars impact the distal region of alveolar bone of adjacent second molars. The periodontal condition of maxillary second molars for which the neighboring third molars were missing (NM3- group) and those with intact non-impacted third molars (NM3+ group) was analyzed in a retrospective study. Using CBCT, the patients were categorized based on the presence or absence of periodontitis, and the alveolar bone resorption parameters in the distal area of the second molars were measured. A total of 135 patients with 200 maxillary second molars were enrolled in this retrospective study. Compared to the NM3- group, the second molars of the NM3+ group exhibited greater odds of increasing alveolar bone resorption in the distal region (health, OR = 3.60; periodontitis, OR = 7.68), regardless of the presence or absence of periodontitis. In healthy patients, factors such as female sex (OR = 1.48) and age above 25 years old (OR = 2.22) were linked to an elevated risk of alveolar bone resorption in the distal region of the second molars. In patients with periodontitis, male sex (OR = 3.63) and age above 45 years old (OR = 3.97) served as risk factors. Advanced age, sex, and the presence of non-impacted third molars are risk factors associated with alveolar bone resorption in individuals with adjacent second molars. In addition, the detrimental effects of non-impacted third molars in the population with periodontitis may be exacerbated. From a periodontal perspective, this serves as supportive evidence for the proactive removal of non-impacted third molars.

Prévalence de l'inclusion des dents de sagesse: étude radiologique auprès d'une population nord africaine

Third molars are the most commonly concerned teeth with the impaction. Impacted third molar (ITM) can be associated to various clinical pathologies Aim: To determine the prevalence of ITM, its pattern and associated affections in Tunisian patients. The study reviewed panoramic radiographs of patients consulting the Fattouma Bourguiba University Hospital, Monastir (Tunisia). Orthopantomograms were analyzed to define the prevalence of ITM; its angulation, depth and relation with the anterior border of mandibular ramus. Associated pathologies were also assessed. Seven hundred and thirty patients were included (286 men and 444 women). The age ranged from 19 to 89 years. Half of the patients (50.3%) showed at least one ITM. The total number of ITM was 881 with a statistical difference between arches (respectively 34.3% and 65.7% in the maxilla and in the mandible). The most common number of ITM was two (35.4%). Level C of impaction was observed more frequently in the maxilla and level A in the mandible. The most common angulation was the vertical one for both arches. Seventy six percent of ITM were presented with class II in relation with the anterior border of mandibular ramus. There was no significant difference in the frequency of impaction between gender and sides. The number of ITM associated with pathological conditions was 199 (22.6%). The most frequently observed pathology was the distal caries on the second molars (11.7%) followed by the caries of the third molars (5.2%). The prevalence of ITM among Tunisian patients was high.

The Patterns of Impacted Third Molars and Their Associated Pathologies: A Retrospective Observational Study of 704 Patients.

Background: The study aims to investigate parameters in patients attending Fujairah Dental Center, including assessing the prevalence of impacted teeth, determining the frequency of associated pathological conditions, and evaluating the patterns and angulations of impacted third molars. Methods: It is a retrospective descriptive study of the panoramic radiographs of patients who attended Fujairah Dental Center for dental care between January 2011 and December 2017. The minimum age for inclusion was 17 years. Clinical records were used to obtain the demographic details of patients, such as age, gender, nationality, medical history, and smoking history. Seven hundred and four panoramic radiographs and clinical records of patients were analyzed. The age range was between 17 and 112 years old, with a mean age of 34 years (S.D 13.5). Results: Of the 704 panoramic radiographs evaluated, 236 (33.6%) X-rays showed teeth impaction with a total of 562 impacted teeth in the upper and lower jaws. Five hundred and twenty-five (93.4%) were impacted third molars, and 37 (6.5%) teeth were other kinds of impacted teeth. Females showed a higher frequency of impacted teeth (62.6%) compared to males (37.4%). The highest prevalence of impacted teeth was found in the 17-25 year age group (61%), and the prevalence declined with advancing age. Impacted third molars were more likely to occur in the mandible (57.3%) than in the maxilla (42.7%). Most of the impacted third molars were in the mesioangular position, followed by the vertical position. The evaluation of the depth of impacted third molars demonstrated that level C impaction was the most frequently seen, followed by level B impaction. Impacted third-molar teeth often presented with two roots (60.7%), followed by a single root (31.3%). An evaluation of the relationship between lower third molars and the inferior dental canal (IDC) revealed that the most frequently observed relation was interrupted (61.5%), followed by a distant relation to the ID canal, and 13% were superimposed. The most common morphological pattern of roots of the impacted third molars was either straight-type or curved and dilacerated roots (5.7%). Additionally, the most noticed pathological conditions associated with impacted teeth were carious second molars adjacent to impacted third molars (42%), which was more likely to be seen in the 17-25-year age group, with females having a higher prevalence than males.

Prevalence Of Pathologies Caused By Mandibular Third Molar Tooth Positions

Background: he aim of this study was to evaluate the pathologies caused by mandibular im-pacted third molars in individuals living in the Şanlıurfa region. Materials and Methods: In this retrospective study conducted at Harran University Faculty of Dentistry between 2018 and 2020, panoramic radiographs of 904 patients (525 females, 379 males) were analyzed. The prevalence, impaction and position of third molars, conditions and pathologies related to these teeth were evaluated. Results: 1664 mandibular third molars of 904 patients were analyzed. When the distribution by gender is examined, 42.79% are men and 57.21% are women. In terms of mandibular third molar position, 60.34% of the teeth are vertical. In terms of mandibular third molar eruption level, 61.39% of the teeth are at level A. When we look at pathologies based on teeth, there is 16.81% caries. Conclusions: While third molars may remain without any symptoms for a long period of life, they may cause caries, cysts and bone loss in adjacent teeth. Tooth extraction may be recom-mended prophylactically to prevent third molar teeth from causing greater pathology in later ages.

Effect of mandibular third molars on crowding of mandibular teeth in patients with or without previous orthodontic treatment: a systematic review and meta-analysis.

To assess the scientific evidence related to the role of the mandibular third molars on the late crowding of the lower anterior teeth in patients with or without previous orthodontic treatment. The secondary outcomes included changes in mandibular arch width and arch length. The databases PubMed, Scopus, ProQuest, and Google Scholar were searched from inception until April 2022. The included papers were studies evaluating the role of mandibular third molars on crowding of mandibular anterior teeth in patients of any age and gender, with mandibular third molars impacted or semi-impacted or erupted. Predetermined and prepiloted data collection forms were used to record the necessary information. Thirteen observational studies were included in the present systematic review. Most of them were assigned an overall risk of bias of moderate risk while the rest of them were at high risk. Four studies found an association between the presence of mandibular third molar and mandibular incisor crowding. Finally, seven studies were included in the quantitative analysis. Three different meta-analyses were conducted: for patients (a) with or (b) without previous orthodontic treatment and (c) in combination for patients with and without previous orthodontic treatment. According to the pooled results of all three meta-analyses, random effects model yielded a significant benefit for those without third molars compared to those with third molars regarding crowding, mean Little's irregularity index and mean arch length. Lower third molars may contribute to mandibular crowding and lower arch constriction. Further prospective research of high quality is needed to clarify the impact of third molars on anterior mandibular crowding.

Assessment of the Relation Between Patterns of Third-Molar Impaction and Blood Group: A Retrospective Study.

Background The prevalence of impacted third molars is high in the global general population. The etiology of impacted third molars is not fully understood, but it is thought to result from combined genetic and environmental factors. Some studies have suggesteda link between the blood group and the risk of impacted third molars. This study aimed to investigate the association between the blood group and the presence of impacted third molars and its pattern. Method A total of 856 panoramic radiographs were included in the study. Thethird molars were evaluated for the pattern of third-molar impaction and blood characteristics recorded as ABO group and presence or absence of Rhesus antigen. Results The results showed no significant association between the blood group and the presence of impacted third molars. The prevalence of at least one impacted the third molar was 34.6%. The most common angulation of impacted third molars was vertical (V) (45.1%), followed by mesioangular (MA) (33.7%), distoangular (DA) (13.8%), and horizontal (H) (7.4%). There was no significant association between the blood group and the number of impacted third molars nor between the blood group and the angulation of the impacted third molars. Conclusion This study suggests that the blood group is not a major factor in the development of impacted third molars. However, further studies with larger sample sizes are needed to confirm these findings.

Dentigerous cyst associated with impaction of right maxillary third molar on panoramic radiograph and CBCT: a case report

Objectives: The aim of this case report is to description of a dentigerous cyst associated with impaction of right maxillary third molar on panoramic radiographs and cone-beam computed tomography (CBCT).&#x0D; Case Report: A 61-year-old male patient came to the Radiology Installation of RSGM Saraswati Denpasar to do perform a panoramic radiograph examination of tooth 15 which had cavities, pain and swelling of the upper right cheek. The results of panoramic radiograph examination showed tooth 15 had caries reaching the pulp and there was a radiolucent lesion at the apikal tooth 15, there was a radiolucent lesion from the mesio-distal CEJ on the crown of the maxillary right third molar that had not erupted, the borders were well-defined, corticated, unilocular, involving the apical of teeth 15,16 and 17. A few days later the patient came back to do CBCT to see more clearly the boundaries, diameter of the lesion and see the relationship of the lesion with surrounding structure.&#x0D; Conclusion: Panoramic radiography and CBCT can be used as a supporting examination in making a diagnosis. The dentigerous cyst associated with impacted right maxillary third molar is clearly visible on the panoramic radiograph and CBCT so that it can assist in planning the appropriate treatment for the patient.&#x0D;

OPG Based Study to Analyze Essential Parameters of Impacted Lower Third Molar among North Malaysian Population: A Retrospective Study

Background: The third molar in permanent dentition is the last tooth to be erupted, the lack of space causes uneruption. Purpose: To determine the difference in various variables between erupted and impacted lower third molar group. Methods: Quasy experimental study done at the AIMST Dental Institute, comprised 200 patients OPG’s were divided into two groups; Group A - erupted, while Group B - impacted mandibular third molars. Results: The third molar angulation in group A was 84.32 ± 11.59 and group B 64.15 ± 30.92 with P value 0.000. The Mesioangular slope of the third molar in group A was 7.14± 9.64 and group B 29.54 ± 35.77 with P value 0.000. The second molar angulation in group A was 88.32 ± 7.59 and group B 86.58± 15.06 with P value 0.302. Gonial angle in group A was 123.02 ± 7.60 and group B 120.08 ± 8.3 with P value 0.010. The third molar mesio-distal crown width in group A was 14.15 ± 1.28 and group B 14.47 ± 1.17 with P value 0.067. Retromolar space in group A was 19.09 ± 2.97 and group B 13.54± 2.96 with P value 0.000. The anterior-posterior distance of the arch of the erupted third molar in group A was 58.88 ±6.23 and group B 62.31 ± 5.75 with P value 0.007. Conclusion: The impaction of third molar is greatly associated with angulation of third molar, mesioangular slope of the third molar and retromolar space.

Effect of Mesioangular Impaction of the Mandibular Third Molars on the Adjacent Mandibular Second Molars: An Imaging Study.

To investigate the effect of mesioangular impaction of the mandibular third molars on distal caries and distal bone loss (DBL) in the adjacent mandibular second molars to provide a basis for prophylactic impacted third molar extraction. We retrospectively analyzed panoramic radiographs of 736 patients with mesioangularly impacted mandibular third molars at the Department of Stomatology, Shanghai Fifth People's Hospital. The chi-square test, the Kruskal-Wallis test, and logistic regression were performed to analyze the relationship of patient age, sex, mesial inclination angle, distal caries, and DBL in the mandibular second molars. Patient aged over 30 years and a mesial inclination angle > 30° were risk factors for distal caries in the mandibular second molars (p < 0.05). Patients aged over 20 years and a mesial inclination angle of 60°-90° were risk factors for DBL (p < 0.05). In patients with mesioangularly impacted mandibular third molars, age and the mesial inclination angle were positively correlated with the severity of distal caries and DBL in the adjacent mandibular second molars. These findings could guide dental practitioners to prevent complications of the adjacent molars during early prophylactic extraction of the mandibular third molars with mesioangular inclination.