What kind of third molars are disease-free in a population aged 30 to 93 years?

How the Loss of Second Molars Corresponds with the Presence of Adjacent Third Molars in Chinese Adults: A Retrospective Study

Third molars (M3s) can increase the pathological risks of neighboring second molars (M2s). However, whether the M3 presence affects M2 loss remains unknown. This retrospective study aimed to reveal the reasons for M2 loss and how M2 loss relates to neighboring M3s. The medical records and radiographic images of patients with removed M2(s) were reviewed to analyze why the teeth were extracted and if those reasons were related to adjacent M3s. Ultimately, 800 patients with 908 removed M2s were included. In the included quadrants, 526 quadrants with M3s were termed the M3 (+) group, and the other 382 quadrants without M3s were termed the M3 (−) group. The average age of patients in the M3 (+) group was 52.4 ± 14.8 years and that of the M3 (−) group was 56.7 ± 14.9 years, and the difference between the two groups was statistically significant (p < 0.001). Of the 908 M2s, 433 (47.7%) were removed due to caries and sequelae and 300 (33.0%) were removed due to periodontal diseases. Meanwhile, 14.4% of the M2s with adjacent M3s were removed due to distal caries and periodontitis, which were closely related to the neighboring M3s; this percentage was much lower when M3 were absent (1.8%). Additionally, 42.2% of M3s were removed simultaneously with neighboring M2s. The presence of M3s, regardless of impaction status, was associated with an earlier loss of their neighboring M2s.

Diagnostic Aspects of an Included Third Molar in an 88-Year-Old Patient: A Case Report and Literature Review

Included third molars in elderly patients are quite rare in dental practice, and therefore easily misdiagnosed, because these teeth are usually extracted in youth. Additional challenges to correctly diagnosing such a dental condition, and its associated complications, arise from frequent co-morbidities in elderly patients, and from difficult communication with the patient. We report a case of an 88-year-old female patient, who presented in the dental emergency room complaining of a discomfort caused by the sharp edges of her lower incisors, and requesting their extraction; the final diagnosis, of suppurated pericoronitis at tooth 48, was concluded based on the clinical elements and X-ray examination.

Comparative Study between the Combination of Dexamethasone and Bupivacaine for Third Molar Surgery Postoperative Pain: A Triple-Blind, Randomized Clinical Trial

Objectives: To compare the possible benefits of the combination of dexamethasone–bupivacaine with articaine–epinephrine as an anaesthetic block after third molar surgery. Materials and Methods: Triple-blind, randomized, controlled, parallel, phase 3 clinical trial. Two groups: experimental (93 patients) with standard anaesthetic block: 40/0.005 mg/mL articaine–epinephrine and submucosal reinforcement with 0.8 mg dexamethasone–5% bupivacaine; and control group (91 patients) with standard block: 40/0.005 mg/mL articaine–epinephrine. The surgery consisted of the extraction of the impacted mandibular third molar by performing a procedure following the same repeatable scheme. The visual analogue scale (VAS) was used to analyse postoperative pain. Results: Groups were homogeneous, without significant differences related to epidemiological variables. Postoperative pain among the first, second, and seventh postoperative days was statistically significantly lower in the experimental group compared to the control group (p < 0.001). Drug consumption was lower in the experimental group throughout the study period (p < 0.04). Conclusion: Bupivacaine is an alternative to articaine in oral surgery, being more effective in reducing postoperative pain by reducing patients’ scores on the VAS as well as their consumption of analgesic drugs after surgery.

Removal of nonimpacted third molars alters the periodontal condition of their neighbors clinically, immunologically, and microbiologically

Considering the adverse effects of nonimpacted third molars (N-M3s) on the periodontal health of adjacent second molars (M2s), the removal of N-M3s may be beneficial to the periodontal health of their neighbors. This study aimed to investigate the clinical, immunological, and microbiological changes of the periodontal condition around M2s following removal of neighboring N-M3s across a 6-month period. Subjects with at least one quadrant containing an intact first molar (M1), M2, and N-M3 were screened and those who met the inclusion criteria and decided to receive N-M3 extraction were recruited in the following investigation. M2 periodontal condition was interrogated before M3 extraction (baseline) and at 3 and 6 months postoperatively. Improvements in clinical periodontal indexes of M2s in response to their adjacent N-M3 removal, along with changes in inflammatory biomarkers among gingival crevicular fluid (GCF) and the composition of subgingival plaque collected from the distal sites of the M2s of the targeted quadrant were parallelly analyzed. Complete data of 26 tooth extraction patients across the follow-up period were successfully obtained and subsequently applied for statistical analysis. Compared to the baseline, the periodontal condition of M2s was significantly changed 6 months after N-M3 removal; specifically, the probing depth of M2s significantly reduced (P < 0.001), the matrix metalloproteinase (MMP)-8 concentration involved in GCF significantly decreased (P = 0.025), and the abundance of the pathogenic genera unidentified Prevotellaceae and Streptococcus significantly decreased (P < 0.001 and P = 0.009, respectively). We concluded that N-M3 removal was associated with superior clinical indexes, decreased GCF inflammatory biomarkers, and reduced pathogenic microbiome distribution within the subgingival plaque. Although the retention or removal of N-M3s continues to be controversial, our findings provide additional evidence that medical decisions should be made as early as possible or at least before the neighboring teeth are irretrievably damaged.

Radiological risk indicators for persistent postoperative morbidity after third molar removal

OBJECTIVES

Although panoramic radiographs are extensively studied for diagnosis and preoperative planning in third molar surgery, research on the predictive value of this radiographic information regarding the postoperative recovery of patients remains underexploited. This prospective cohort study aimed to assess the potential relationship between radiologic risk indicators and persistent postoperative morbidity, in 1009 patients undergoing 2825 third molar extractions in context of the M3BE study.

METHODS

Two observers evaluated ten radiographic parameters: vertical and horizontal eruption status, third molar orientation, surgical difficulty, nerve relation, maxillary sinus relation, presence of periapical and pericoronal radiolucencies, caries, and third or second molar resorption. Patients' postoperative recovery was recorded 3 and 10 days after surgery. Univariate logistic regression was performed to assess potential associations between radiographic risk indicators and persistent postoperative morbidity.

RESULTS

Deep impactions were significantly associated with the persistence of postoperative pain, trismus and swelling until 10 days after surgery, prolonged need for pain medication, and the inability to resume daily activities and work/studies. Pericoronal radiolucencies and resorption were significantly associated with persistent morbidity and a longer recovery time, whereas caries and periapical lesions were linked to a shorter recovery time.

CONCLUSION

Based on the results of this study, clinicians may better inform patients at risk for persistent postoperative discomfort according to what was preoperatively diagnosed on the panoramic radiograph.

CLINICAL RELEVANCE

Preoperative panoramic radiographs contain information about patients at risk of prolonged recovery after third molar removal. Several risk indicators for persistent postoperative morbidity were identified.

Evaluation of Panoramic Radiographs in Relation to the Mandibular Third Molar and to Incidental Findings in an Adult Population

OBJECTIVES

 The aim was to evaluate the characteristics of the mandibular third molars, especially in relation to the inferior alveolar nerve. Further aims were to investigate incidental findings in panoramic radiographs in an adult population, and to investigate image quality related to patient positioning.

MATERIALS AND METHODS

 From a previous study with 451 randomly selected adult participants who lived in Sweden, 442 panoramic radiographs from four dental public health clinics were used. The third molars' characteristics and relation to inferior alveolar nerve were evaluated. Incidental findings and patient positioning were recorded.

STATISTICAL ANALYSIS

 Frequency analysis was used to investigate the occurrence of all findings and their possible interconnections. Whether the patients' age or gender had an impact or not was also analyzed.

RESULTS

 The third molars were erupted in vertical position among 73% regardless of age. When retained or semi-retained, they were most commonly in mesioangular positions. The inferior alveolar nerve was located inferior to the roots in 52%, whereas an overlapped position was most common if the third molar was retained (90%), semi-retained (83%) or the age was less than 30 years (66%). Common incidental findings were apical radiolucencies, idiopathic osteosclerosis, and tooth fragments. Suboptimal patient positioning was found in one-third of the radiographs.

CONCLUSIONS

 Panoramic radiography is a useful method to evaluate third molar prior to surgical removal and may be the only image required. Most incidental findings on panoramic radiographs does not seem to require any further odontological management.

Does Retaining Third Molars Result in the Development of Pathology Over Time? A Systematic Review

PURPOSE

The present systematic review was conducted to assess the available literature on pathologies associated with third molar retention.

MATERIALS AND METHODS

A systematic literature search was conducted in MEDLINE (PubMed), Embase, and Cochrane Library and reported in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Relevant reports were selected using predefined inclusion and exclusion criteria. Pathology related to third molar retention included caries, periodontal pathology, second molar external root resorption, and pathologic widening of the third molar pericoronal space. The methodologic quality of each study was reviewed using a pathology-specific tool to assess the risk of bias.

RESULTS

A total of 37 studies were included for qualitative analysis. The available data showed that asymptomatic retained third molars frequently become diseased with increasing age of the patient and increased retention time. Caries and periodontal pathology were most frequently observed, especially in partially erupted third molars and mesially inclined mandibular third molars. Overall, the available data were regarded as medium to fair quality evidence.

CONCLUSIONS

The available data have revealed that retained asymptomatic third molars rarely remain disease-free over time. Increasing age and, thus, increasing retention time seemed associated with greater disease prevalence. Well-designed, prospective follow-up studies are needed to substantiate the clinical management of asymptomatic disease-free third molars.

Surgical removal versus retention for the management of asymptomatic disease-free impacted wisdom teeth

BACKGROUND

Prophylactic removal of asymptomatic disease-free impacted wisdom teeth is the surgical removal of wisdom teeth in the absence of symptoms and with no evidence of local disease. Impacted wisdom teeth may be associated with pathological changes, such as pericoronitis, root resorption, gum and alveolar bone disease (periodontitis), caries and the development of cysts and tumours. When surgical removal is performed in older people, the risk of postoperative complications, pain and discomfort is increased. Other reasons to justify prophylactic removal of asymptomatic disease-free impacted third molars have included preventing late lower incisor crowding, preventing damage to adjacent structures such as the second molar or the inferior alveolar nerve, in preparation for orthognathic surgery, in preparation for radiotherapy or during procedures to treat people with trauma to the affected area. Removal of asymptomatic disease-free wisdom teeth is a common procedure, and researchers must determine whether evidence supports this practice. This review is an update of an review originally published in 2005 and previously updated in 2012 and 2016.

OBJECTIVES

To evaluate the effects of removal compared with retention (conservative management) of asymptomatic disease-free impacted wisdom teeth in adolescents and adults.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 10 May 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2019, Issue 4), MEDLINE Ovid (1946 to 10 May 2019), and Embase Ovid (1980 to 10 May 2019). The US National Institutes of Health Trials Registry (ClinicalTrials.gov)and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. .

SELECTION CRITERIA

We included randomised controlled trials (RCTs), with no restriction on length of follow-up, comparing removal (or absence) with retention (or presence) of asymptomatic disease-free impacted wisdom teeth in adolescents or adults. We also considered quasi-RCTs and prospective cohort studies for inclusion if investigators measured outcomes with follow-up of five years or longer.

DATA COLLECTION AND ANALYSIS

Eight review authors screened search results and assessed the eligibility of studies for inclusion according to the review inclusion criteria. Eight review authors independently and in duplicate conducted the risk of bias assessments. When information was unclear, we contacted the study authors for additional information.

MAIN RESULTS

This review update includes the same two studies that were identified in our previous version of the review: one RCT with a parallel-group design, which was conducted in a dental hospital setting in the United Kingdom, and one prospective cohort study, which was conducted in the private sector in the USA. Primary outcome No eligible studies in this review reported the effects of removal compared with retention of asymptomatic disease-free impacted wisdom teeth on health-related quality of life Secondary outcomes We found only low- to very low-certainty evidence of the effects of removal compared with retention of asymptomatic disease-free impacted wisdom teeth for a limited number of secondary outcome measures. One prospective cohort study, reporting data from a subgroup of 416 healthy male participants, aged 24 to 84 years, compared the effects of the absence (previous removal or agenesis) against the presence of asymptomatic disease-free impacted wisdom teeth on periodontitis and caries associated with the distal aspect of the adjacent second molar during a follow-up period of three to over 25 years. Very low-certainty evidence suggests that the presence of asymptomatic disease-free impacted wisdom teeth may be associated with increased risk of periodontitis affecting the adjacent second molar in the long term. In the same study, which is at serious risk of bias, there is insufficient evidence to demonstrate a difference in caries risk associated with the presence or absence of impacted wisdom teeth. One RCT with 164 randomised and 77 analysed adolescent participants compared the effect of extraction with retention of asymptomatic disease-free impacted wisdom teeth on dimensional changes in the dental arch after five years. Participants (55% female) had previously undergone orthodontic treatment and had 'crowded' wisdom teeth. No evidence from this study, which was at high risk of bias, was found to suggest that removal of asymptomatic disease-free impacted wisdom teeth has a clinically significant effect on dimensional changes in the dental arch. The included studies did not measure any of our other secondary outcomes: costs, other adverse events associated with retention of asymptomatic disease-free impacted wisdom teeth (pericoronitis, root resorption, cyst formation, tumour formation, inflammation/infection) and adverse effects associated with their removal (alveolar osteitis/postoperative infection, nerve injury, damage to adjacent teeth during surgery, bleeding, osteonecrosis related to medication/radiotherapy, inflammation/infection).

AUTHORS' CONCLUSIONS

Insufficient evidence is available to determine whether asymptomatic disease-free impacted wisdom teeth should be removed or retained. Although retention of asymptomatic disease-free impacted wisdom teeth may be associated with increased risk of periodontitis affecting adjacent second molars in the long term, the evidence is very low certainty. Well-designed RCTs investigating long-term and rare effects of retention and removal of asymptomatic disease-free impacted wisdom teeth, in a representative group of individuals, are unlikely to be feasible. In their continuing absence, high quality, long-term prospective cohort studies may provide valuable evidence in the future. Given the current lack of available evidence, patient values should be considered and clinical expertise used to guide shared decision-making with people who have asymptomatic disease-free impacted wisdom teeth. If the decision is made to retain these teeth, clinical assessment at regular intervals to prevent undesirable outcomes is advisable.

Impacts of non-impacted third molar removal on the periodontal condition of adjacent second molars

OBJECTIVE

The aim of this study was to determine how the removal of non-impacted third molars (N-M3s) affects the periodontal status of neighboring second molars (M2s).

SUBJECTS AND METHODS

The periodontal condition of M2s for which the neighboring N-M3s were removed (more than 6 months previously) and those with intact N-M3s was analyzed in a cross-sectional observation study. In an additional case series, periodontal changes in M2s in response to adjacent N-M3 removal were observed during a 6-month follow-up period.

RESULTS

A total of 457 patients with 1,301 M2s were enrolled in this cross-sectional observational study. Compared to M2s with neighboring N-M3s, M2s without neighboring N-M3s (teeth removed more than 6 months previously) exhibited a 0.27-mm reduction in the average pocket depth (PD) (p < .001) and a 0.38-fold reduced risk of at least one probing site with PD ≥5 mm (PD5+) (p < .001). Subsequently, a 41-case follow-up study showed that 6 months after neighboring N-M3 extraction, the PD of the M2s decreased by 0.31 mm (p < .001), while the incidence of PD5+ decreased by 21.9% when compared to the parameters detected before tooth extraction (p = .004).

CONCLUSIONS

Removing N-M3s was associated with an improved periodontal condition in neighboring M2s.

Prevalence of third molars determined by panoramic radiographs in a population-based survey of adult Finns

OBJECTIVES

The aim of the study was to examine the prevalence of third molars in panoramic radiographs in a population-based study of adults aged ≥30 years.

METHODS

Out of a sample of 8028 inhabitants of Finland, selected with two-staged stratified cluster-sampling method for the Health 2000 Survey, 5989 participated in clinical oral examination and panoramic radiography. Mean age was 52.5 years (SD 14.6; range 30-97 years). The following variables were included in the analysis: participant characteristics, clinical number of all teeth, and radiographic prevalence and characteristics of third molars. Statistics included chi-squared, Fisher's exact, and Kruskal-Wallis tests and SAS-SUDAAN calculations.

RESULTS

A total of 5912 third molars in 47.8% of the study population were recorded from panoramic radiographs. At least one impacted third molar was found in 21.9% of the study population. More than half (57.3%) of the remaining third molars were located in the mandible. A preponderance of participants with all third molars missing were observed in the oldest age group, women, those with lower education and those living in the countryside. Third molars or remnants thereof were observed radiographically in 3.9% of clinically edentulous study population.

CONCLUSIONS

The panoramic radiographs disclosed many remaining third molars in adult Finns aged ≥30 years. One-third of the third molars located impacted which may cause unexpected need for care.

A retrospective cohort study on reasons to retain third molars

The primary goal of this study was to identify and quantify indications for retaining third molars. This retrospective cohort study included 1682 patients (818 male, 864 female; mean age 31 years) who were referred to the University Hospitals Leuven for third molar removal. Eight reasons for retaining the third molars were identified: (1) risk of damaging adjacent structures, (2) compromised health status, (3) adequate space for eruption, (4) third molar serves as abutment tooth, (5) orthodontic reasons, (6) eruption into proper occlusion, (7) symptomless third molars in patients >30 years old, and (8) patient preference. To compare these categories between sex and age groups, a generalized linear model for binary data was fitted with a logit link. A total of 1149 third molars in 548 patients were not extracted. The most frequent reasons for retaining third molar teeth were: eruption into proper occlusion (31.9%), patient preference (31.5%), and symptomless third molars in patients >30 years old (17.5%). Compromised health status and advanced age were often included in the decision regarding whether to retain the third molars. One third of the referred patients had reasons to retain one or more third molars. These findings might facilitate the future development of a consensus statement.

Relationship between the Position of Impacted Third Molars and External Root Resorption of Adjacent Second Molars: A Retrospective CBCT Study

BACKGROUND AND OBJECTIVES

Impacted third molars (ITM) are the most commonly-impacted teeth. There is a risk for ITM to cause a number of pathological conditions, and external root resorption (ERR) of adjacent teeth is one of the most prevalent. Retaining or prophylactic extraction of ITM is a polemic topic. External root resorption of adjacent teeth is one of possible indications for prophylactic removal of ITM. The aim of this study was to assess the relationship between external root resorption (ERR) on the distal aspect of second molars' roots and positional parameters of ITM. Methods: Cone beam computed tomography scans of 109 patients (41 males, 68 females; mean age 26.4 ± 7.9 years) with 254 ITM (131 in the maxilla and 123 in the mandible) were retrospectively analyzed. Positional parameters of ITM (mesio-distal position, angulation, impaction depth, and available eruption space) were evaluated. The presence, location, and depth of ERR of adjacent second molars were assessed. Results: Analysis showed a relationship between ITM impaction depth, mesial inclination angle, and the presence of ERR. Mesial inclination angle of more than 13.6° increased the odds of ERR occurrence by 5.439 (95% CI, 2.97-9.98). ITM presence at the level of ½ of roots of the adjacent second molar or more apically increased the odds of ERR occurrence by 2.218 (95% CI, 1.215-4.048). No significant correlation was detected between the occurrence of ERR and patient age, gender, or the available eruption space in the mandible. Depth of ERR did not depend on its location. Conclusions: Incidence of ERR in second molars is significantly associated with mesial inclination and a deep position of ITM.