What is the risk of future extraction of asymptomatic third molars? A systematic review

Third molar-related knowledge, attitudes, behaviors, and medical history of 904 Chinese adults: a cross-sectional survey

This study investigated the perceptions and medical history of third molars (M3s) and assessed the prevalence of visible M3s (V-M3s) among 904 Chinese adults. The enrolled participants were interviewed to complete a structural questionnaire focused on sociodemographic information and their understanding of, attitudes toward, behaviors regarding, and medical history with respect to M3s. In addition, the number of V-M3s in the cohort was determined by oral examination. Logistic regression analysis was performed to explore the association between individuals' sociodemographic characteristics and their perception of M3s or the presence of V-M3s. The Chi-square test was used to compare the actions taken against symptomatic M3s and the corresponding outcomes among different groups divided according to respondents' sociodemographic factors. In total, 904 completed questionnaires were gathered and analyzed. Nearly half (43.9%) of the respondents knew nothing about M3s, and only 12.7% provided correct answers to all the questions asked. Male sex, older age, occupation involving physical labor, and no previous dental experience were active factors in unawareness of M3s. Male sex was also significantly associated with the presence of at least one V-M3 and negative behavior about symptomatic M3s. In terms of medical history, 192 participants reported having had at least one M3 extracted (438 in total), and 72.6% of the M3s were removed due to the presence of related symptoms or pathologies. In conclusion, the population investigated had a shortage of knowledge about M3s and adopted negative attitudes and actions about M3-related problems.

What Are the Effects of Methylprednisolone Injection Into the Masseter and Gluteal Muscle on Pain, Edema and Trismus After Impacted Lower Third Molar Surgery? A Randomized Clinical Trial

PURPOSE

Methylprednisolone is widely administered after impacted third molar surgery. This study compared the effect of methylprednisolone injection into the masseter and gluteal muscle on pain, edema, and trismus after impacted lower third molar surgery.

METHODS

This was a single-blind placebo-controlled randomized clinical trial. Sixty patients with an impacted lower third molar were included and randomly assigned into 3 groups. Each group received 1 of the following medications half an hour before surgery: Group I: 40 mg methylprednisolone injected into masseter muscle; Group II: 40 mg methylprednisolone injected into gluteal muscle; Group III: considered as control group with no intervention. The level of pain was recorded 1, 5, and 7 days after surgery using visual analog scale, and the amount of edema was measured 5 and 7 days after surgery using ultrasound imaging. The amount of trismus was measured 5 and 7 days after surgery based on the distance between incisor edge of upper and lower centrals. Friedman test was used to compare the level of pain, trismus and edema in each group at different times. Kruskal-Wallis test was used to compare the level of pain, trismus and edema among different groups at each time. Significance level was set at P < .05.

RESULTS

There was no significant difference among the 3 groups (a total of 60 patients (31 females and 29 males), aged 19 to 35 years) considering edema (P = .250, CI = 0.22 ± 0.42), trismus (P = .337, CI = -5.93 ± 2.22) and pain (P = .285, CI = -2.91 ± 0.40) relief.

CONCLUSIONS

Postsurgical pain, edema, and trismus were not reduced by intramuscular injection of methylprednisolone before third molar surgery.

Treatment of Osseous Defects after Mandibular Third Molar Removal with a Resorbable Alloplastic Grafting Material: A Case Series with 1- to 2-Year Follow-Up

Mandibular third molar (M3) surgical extraction may cause periodontal complications on the distal aspect of the root of the adjacent mandibular second molar (M2). Patients older than 26 years with periodontal pathology on the distal surface of the M2 and a horizontal/mesioangular impacted M3 may benefit from bone regenerative therapy at the time of surgery. In this prospective case series, an alloplastic fully resorbable bone grafting material, consisting of beta-tricalcium phosphate (β-TCP) and calcium sulfate (CS), was used for the treatment of the osseous defects after the removal of horizontal or mesioangular M3s in 4 patients older than 26 years. On presentation, the main radiological finding in all patients, indicating periodontal pathology, was the absence of bone between the crown of the M3 and the distal surface of the root of the M2. To evaluate the treatment outcome, bone gain (BG) was assessed by recording the amount of bone defect (BD) at the time of surgical removal (T0) and at the time of final follow-up (T1) 1 or 2 years post-operatively. The healing in all cases was uneventful, with no complications associated with the use of the alloplastic grafting material. Clinical and radiological examination at T1 revealed that all extraction sites were adequately restored, with significant BG of 6.07 ± 0.28 mm. No residual pathological pockets on the distal surface of the M2 were detected. Pocket depth (PD) at T1 was 2 ± 0.71 mm. Within the limitations of this case series, the results suggest that β-TCP/CS can support new bone formation at M3 post-extraction sites where bone regeneration methods are indicated, thus reducing the risk of having persistent or developing new periodontal problems at the adjacent M2.

Influence of operator's professional experience in the postoperative course after surgical extrac-tion of the impacted lower third molar: A pilot study

Background

Third molars are present in 96.6% of humans, although they do not always erupt completely. Between 9.5% and 73% of them remain impacted. Surgical removal of impacted third molars is the most common practice in oral and maxillofacial surgery. This procedure results in traumatism and, consequently, the postoperative phase will involve symptomatology. It is uncommon to find studies that directly relate postoperative symptomatology and the operator’s experience. The aim of this study was to determine the differences regarding postoperative symp-tomatology in patients undergoing the bilateral extraction of lower impacted third molars and according to the operator’s experience.

Material and Methods

A prospective cohort double-blind study was conducted in 50 healthy patients (100 molar extractions) to whom both lower third molars were removed by two dentists with different degree of professional experience. The extractions were randomly assigned with a split–mouth design. If an operator extracted the lower third molar on one side, the other operator extracted the contralateral one. The variables studied after four days of postoperative period were Pain (EVA scale), Inflammation and Trismus, in addition to intraoperative time and local anesthesia administered.

Results

Statistically significant differences were detected in the time of intervention and in trismus, since the most experienced operator always needed less time and caused higher degree of trismus. However, this does not entail more inflammation or pain in patients, so there are no relevant differences between operators with more or less experience (p>0.05).

Conclusions

The postoperative period is more favorable for the most experienced operator, although the results do not vary in a relevant manner between them.

Key words:Preemptive analgesia, dental extraction, cyclooxygenases, real-time polymerase chain reaction.

Evidence-based clinical decision making for the management of patients with periodontal osseous defect after impacted third molar extraction: A systematic review and meta-analysis

Background/purpose

Extraction of impacted mandibular third molar (MTM) is one of the most common procedures in clinical dental treatment; building a decision tree to perform MTM extraction can be prudent in alleviating periodontal diseases. This study is to review the latest research on the management of periodontal osseous defect (POD) after MTM extraction and rebuild a new clinical decision tree.

Materials and methods

Current study was conducted according to PRISMA statement. Medline, Embase, Scopus, and Google Scholar were searched concerning treatment of MTM extraction up to Oct.2019. Three focused questions revolving around asymptomatic versus disease site, age, and necessity of ridge preservation after >6 months follow up will be answered.

Results

A total of 7 studies were included for meta-analysis. Evidences were inadequate in regards to asymptomatic vs disease site of MTM extraction in the long-term follow-up. For patients with age <25 years, postoperative probing depth (PD) always remained at < 4 mm. However, for patients with age >25 years with initial PD > 7 mm, residual pockets still remained at 5 mm. For ridge preservation, significant positive effect in reduction of second molar distal site PD was observed, regardless of different biomaterials being placed (z = 4.69, p < 0.00001).

Conclusion

Age is of utmost importance in preoperative evaluation during impacted MTM extraction. The timing for ridge preservation is essential determinant for achieving optimal treatment outcome. The clinical decision tree as proposed could serve as guidance when dealing with POD after impacted MTM extraction.

Prophylactic removal of impacted mandibular third molars: a systematic review and economic evaluation

BACKGROUND

Impacted third molars are third molars that are blocked, by soft tissue or bone, from fully erupting through the gum. This can cause pain and disease. The treatment options for people with impacted third molars are removal or retention with standard care. If there are pathological changes, the current National Institute for Health and Care Excellence guidance states that the impacted third molar should be removed.

OBJECTIVE

The objective of this study was to appraise the clinical effectiveness and cost-effectiveness of the prophylactic removal of impacted mandibular third molars compared with retention of, and standard care for, impacted third molars.

METHODS

Five electronic databases were searched (1999 to 29 April 2016) to identify relevant evidence [The Cochrane Library (searched 4 April 2016 and 29 April 2016), MEDLINE (searched 4 April 2016 and 29 April 2016), EMBASE (searched 4 April 2016 and 29 April 2016), EconLit (searched 4 April 2016 and 29 April 2016) and NHS Economic Evaluation Database (searched 4 April 2016)]. Studies that compared the prophylactic removal of impacted mandibular third molars with retention and standard care or studies that assessed the outcomes from either approach were included. The clinical outcomes considered were pathology associated with retention, post-operative complications following extraction and adverse effects of treatment. Cost-effectiveness outcomes included UK costs and health-related quality-of-life measures. In addition, the assessment group constructed a de novo economic model to compare the cost-effectiveness of a prophylactic removal strategy with that of retention and standard care.

RESULTS

The clinical review identified four cohort studies and nine systematic reviews. In the two studies that reported on surgical complications, no serious complications were reported. Pathological changes due to retention of asymptomatic impacted mandibular third molars were reported by three studies. In these studies, the extraction rate for retained impacted mandibular third molars varied from 5.5% to 31.4%; this variation can be explained by the differing follow-up periods (i.e. 1 and 5 years). The findings from this review are consistent with the findings from previous systematic reviews. Two published cost-effectiveness studies were identified. The authors of both studies concluded that, to their knowledge, there is currently no economic evidence to support the prophylactic removal of impacted mandibular third molars. The results generated by the assessment group's lifetime economic model indicated that the incremental cost-effectiveness ratio per quality-adjusted life-year gained for the comparison of a prophylactic removal strategy with a retention and standard care strategy is £11,741 for people aged 20 years with asymptomatic impacted mandibular third molars. The incremental cost per person associated with prophylactic extraction is £55.71, with an incremental quality-adjusted life-year gain of 0.005 per person. The base-case incremental cost-effectiveness ratio per quality-adjusted life-year gained was found to be robust when a range of sensitivity and scenario analyses were carried out.

LIMITATIONS

Limitations of the study included that no head-to-head trials comparing the effectiveness of prophylactic removal of impacted mandibular third molars with retention and standard care were identified with the assessment group model that was built on observational data. Utility data on impacted mandibular third molars and their symptoms are lacking.

CONCLUSIONS

The evidence comparing the prophylactic removal of impacted mandibular third molars with retention and standard care is very limited. However, the results from an exploratory assessment group model, which uses available evidence on symptom development and extraction rates of retained impacted mandibular third molars, suggest that prophylactic removal may be the more cost-effective strategy.

FUTURE WORK

Effectiveness evidence is lacking. Head-to-head trials comparing the prophylactic removal of trouble-free impacted mandibular third molars with retention and watchful waiting are required. If this is not possible, routine clinical data, using common definitions and outcome reporting methods, should be collected.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016037776.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 30. See the NIHR Journals Library website for further project information.

Factors Influencing the Localization of Mandibular Third Molars in Twins

PURPOSE

The aim of the present study was to evaluate the genetic and environmental factors influencing the localization of mandibular third molars by analyzing the panoramic radiographs of twins. We examined the mandibular third molars of Japanese monozygotic (MZ) and dizygotic (DZ) twins recruited by the Osaka University Center for Twin Research.

MATERIALS AND METHODS

The present study included 49 pairs (98 participants) of MZ twins and 11 pairs (22 participants) of DZ twins. Using panoramic radiography, we evaluated the degree of eruption of mandibular third molars according to the height of the alveolus bone and the third molar space/crown width ratio. Using co-twin control analysis and a generalized linear mixed model, we evaluated the effects of various factors, including gender, age, body height, number of teeth, length of the lower dental arch, existence of a second molar, bruxism, and previous orthodontic therapy.

RESULTS

Body height, third molar space/crown width ratio, and length of the mandibular dental arch were related to the degree of mandibular third molar eruption and were strongly influenced by genetic factors rather than common or unique environmental factors.

CONCLUSIONS

The degree of third molar eruption was more similar among MZ twins than among DZ twins; therefore, genetic factors can be expected to have more significant influence than will environmental factors. These results can help identify the trend of third molar eruption from a young age, allowing us to advise the early extraction of mandibular third molars for patients with a short stature, narrow retromolar space, or short mandibular dental arch. In addition, if the genes that influence the degree of eruption were identified, we would be better equipped to predict an individual's risk of impaction, and indications for extraction might change.

Association Between Third Molar Impaction Status and Angle or Condylar Fractures of the Mandible: A Retrospective Analysis

PURPOSE

The aim of our study was to evaluate the correlations between mandibular third molar impaction status and mandibular angle and condylar fractures.

MATERIALS AND METHODS

This retrospective cross-sectional study included patients with unilateral and isolated angle or condylar fractures. Patient records and panoramic radiographs were evaluated. The predictor variables included the presence, impaction status (Pell and Gregory [P&G] classification), and angulation (Winter classification) of the third molar. The outcome variable was the type of fracture, whereas other predictor variables included demographic factors such as age, gender, and fracture etiology. Bivariate (χ² test) and logistic regression analyses were conducted to estimate the associations between variables and the outcome.

RESULTS

The sample was composed of 164 angle fracture (mean age, 31.6 ± 12.3 years; 83.5% male) and 115 condylar fracture (mean age, 41.9 ± 16.8 years; 76.5% male) patients. A third molar was present in 72.6% of the angle fracture group and 54.8% of the condylar fracture group (P = .002). Deep impactions (classes IC, IIC, IIIB, and IIIC) exhibited an odds ratio (OR) of 3.60 for angle fractures (P < .001). No association was found between tooth angulations and the type of fracture. According to logistic regression analysis, older age (adjusted OR, 1.05; 95% confidence interval [CI], 1.03 to 1.07), P&G class I impaction (OR, 1.86; 95% CI, 1.09 to 3.20), and P&G class A impaction (OR, 1.91; 95% CI, 1.12 to 3.24) were significantly associated with condylar fractures whereas the presence of a third molar (OR, 0.46; 95% CI, 0.28 to 0.76) or P&G class B impaction (OR, 0.287; 95% CI, 0.12 to 0.69) was associated with angular fractures.

CONCLUSIONS

P&G class II or III and class B impaction status was significantly associated with angle fractures, whereas missing or fully erupted (class IA) third molars significantly correlated with condylar fractures.

Prophylactic extraction of non-impacted third molars: is it necessary?

BACKGROUND

The decision of removing a non-impacted 3rd molar, unlike extraction of an impacted 3rd molar, is challenging for dentists as well as patients. This study investigates the pathologies affecting second molars situated adjacent to asymptomatic non-impacted 3rd molars.

METHODS

This retrospective study included digital radiographs of 749 patients taken between April to October 2015. Panoramic radiographs were evaluated for the presence of erupted asymptomatic non-impacted 3rd molars and pathologies on adjacent second molars. The patients were reviewed according to age and gender.

RESULTS

A total of 2342 asymptomatic 3rd molars were assessed in the study based on the inclusion and exclusion criteria, and 2112 of them were found to be non-impacted. The second molars adjacent to non-impacted 3rd molars were shown to be significantly associated with distal caries (25.2%), mesial bone loss (10.5%) and total bone loss (37.2%), i.e., mesial as well as distal bone loss.

CONCLUSIONS

Pathologies of the 3rd molars and teeth adjacent to 3rd molars can occur as a result of multiple factors. Caries and periodontal disease may also occur due to the inaccessibility to maintain oral hygiene. With a regular follow-up schedule, reinforced by the dentist and good oral hygiene, several pathologies that are significantly associated with non-impacted 3rd molars can be prevented and may not require prophylactic extraction.

Assessment of the referral system for surgical removal of third molars at the Dental Faculty, King Saud University

INTRODUCTION

There is compelling evidence that prophylactic extraction of third molars is a health problem that needs to be addressed. In particular, the vast amount of evidence demonstrating complications after removal of third molars, rather than supporting the necessity of removal or the negative effects of retention, raise this concern.

OBJECTIVE

The aim of this study was to investigate the referral system for third molar extraction at our institution by assessing patient opinions and the experience of the oral surgeons and the referring dentists. The main outcome measures of concern were the reasons for third molar extraction, patient awareness about the surgery and the comorbidities that may accompany the surgery.

METHODS

Pilot cross-sectional survey questionnaires were distributed at the Dental Faculty Clinic at King Saud University, from 15 March 2015 to 30 June 2016 by the staff in charge of the patient waiting area, oral surgery clinic, primary care clinic and specialist clinic.

RESULTS

Of 400 potential respondents, 226 completed the survey (response rate: 54%). Of these patients, 91% knew why they had been referred to the oral surgery department, but 73.5% did not understand the surgical extraction procedure or its complications. In total, 45.2% of the patients referred had no signs or symptoms, and 36% were referred for prophylactic reasons. In conclusion, our system needs reassessment. To combat the subjective health practice of routinely referring patients for prophylactic extraction, the role of primary care should be emphasised by implementing a system for regular patient check-ups, and public awareness should be increased.

Impacted lower third molars and distal caries in the mandibular second molar. Is prophylactic removal of lower third molars justified?

Background

The objective of this study was to evaluate the association between the presence of mandibular third molars and the occurrence of carious lesions in the distal aspect of the mandibular second molar.

Material and Methods

A retrospective cohort study comprising 327 lower third molars extracted in the Oral Surgery and Implantology Master’s Degree program of the School of Dentistry of the University of Barcelona (Barcelona, Spain) was carried out. A descriptive and bivariate analysis was made. The diagnosis of caries in the second molar and the position of the mandibular third molar were evaluated through panoramic radiographies.

Results

The sample included 203 patients, 94 males (46.3%) and 109 females (53.7%), with a mean age of 26,8 years and 327 lower third molars. The prevalence of second molar distal caries was 25.4% (95% CI= 20.6% to 30.2%). This pathology was significantly more frequent when the third molar was in a horizontal position (27.7%), when the contact point was at (45,8%) or below (47.0%) the cementoenamel junction (CEJ), and when the distal CEJ of the mandibular second molar and the mesial CEJ of the third molar was 7 to 12 mm apart.

Conclusions

Horizontal lower third molars with contact points at or below the CEJ are more likely to produce distal caries in the mandibular second molars. Due to the high prevalence of this pathology (20.6% to 30.2%), a prophylactic removal of lower third molars with the above-mentioned features might be advisable.

Key words:Second molar, caries, third molar, prophylactic removal.

Nonimpacted Third Molars Affect the Periodontal Status of Adjacent Teeth: A Cross-Sectional Study

PURPOSE

Most previous studies of the effect of third molars (M3s) on the health of adjacent second molars (A-M2s) have focused on impacted M3s (I-M3s). The purpose of this study was to investigate whether nonimpacted M3 (N-M3s) could affect the periodontal status of A-M2s.

PATIENTS AND METHODS

In this cross-sectional study, patients (≥18 years) who had at least 1 quadrant with intact first and second molars and a nonimpacted or absent M3 were enrolled in this study. The periodontal measurements of M2 (6 sites) in the examined quadrants included the gingival index (GI), plaque index (PLI), probing pocket depth (PPD), clinical attachment level (CAL), gingival recession, and bleeding on probing (BOP). The mean GI, PLI, PPD, CAL, and BOP proportion and the proportion with at least 1 site with a PPD of at least 5 mm (PPD5⁺) were compared using the t test or χ² test. The association of PPD5⁺ (percentage) or BOP (percentage) with the presence of N-M3s was assessed using a 2-level logistic regression model (quadrant-based analysis).

RESULTS

One hundred thirty-five patients (43.7% men; 40.6 ± 11.5 yr old) were enrolled in this study. Patients who had at least 1 quadrant with 3 intact molars and an N-M3 were enrolled in group A (105 patients), and patients who had at least 1 quadrant with intact first and second molars without an M3 were enrolled in group B (30 patients). The periodontal parameters (ie, GI, PLI, PPD, CAL, BOP, and PPD5⁺) were markedly greater in group A. When other factors associated with periodontal disease were controlled, N-M3s were associated with the PPD5⁺ (odds ratio = 6.7) and BOP (odds ratio = 4.0) of the A-M2s. Other factors positively associated with A-M2 PPD5⁺ were location on the mandible, age older than 35 years, and smoking.

CONCLUSIONS

The presence of N-M3s is a potential risk factor for the development of periodontitis in A-M2s.

Retention of Asymptomatic Third Molars May be Unwise

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

What is the risk of future extraction of asymptomatic third molars? A systematic review. Bouloux GF, Busaidy KF, Beirne OR, Chuang S-K, Dodson TB. J Oral Maxillofac Surg 2015;73(5):806-11.

SOURCE OF FUNDING

No external funding source is identified although all 5 authors appear to be on the American Association of Oral and Maxillofacial Surgery 3rd Molar Task Force

TYPE OF STUDY/DESIGN

Systematic review.