Influence of tooth sectioning technique and various risk factors in reducing the IAN injury following surgical removal of an impacted mandibular third molar

Removal of Horizontally Impacted Mandibular Third Molars Using the Three-Piece or T-Shaped Tooth Sectioning Method

BACKGROUND

The extraction of horizontally impacted mandibular third molars (HM3) can be a complicated surgery. Appropriate tooth sectioning methods can reduce the operation time and postoperative complications.

PURPOSE

The current study compares operative time and postoperative pain between HM3 removed using the three-piece or T-shaped tooth sectioning techniques.

STUDY DESIGN, SETTING, SAMPLE

A randomized single-blind prospective clinical trial on HM3 extraction was carried out between June and December 2022 in the Department of Oral and Maxillofacial Surgery, the Affiliated Stomatological Hospital, Southwest Medical University. Patients with local or systemic infection, poor oral hygiene, and systemic disease were excluded.

PREDICTOR VARIABLE

The predictor variable was the tooth sectioning method. The subjects were randomized to a three-piece or T-shaped group.

MAIN OUTCOME VARIABLE(S)

The primary outcome variables were the operative time and postoperative pain measured using a visual analog scale (VAS). The secondary outcome variables were the rates of primary bleeding, mouth opening reduction, swelling, patient satisfaction measured using a VAS, and quality of life measured using a postoperative symptom severity scale.

COVARIATES

The covariates included age, sex, side and classification of HM3, and the relationship of HM3 to the inferior alveolar nerve canal.

ANALYSES

The data were analyzed using the independent samples t-test, paired t-test, χ2, and rank sum test. A significance level set at P < .05.

RESULTS

The sample included 60 patients in the three-piece group and 66 patients in the T-shaped group. The operative time of the three-piece group (14.73 ± 3.21 minutes) was shorter than that of the T-shaped group (19.25 ± 4.29 minutes) (P < .05). On days 3 and 7, VAS of pain were 2.24 ± 1.89 and 0.15 ± 0.40 in the three-piece group and 3.95 ± 2.44 and 0.48 ± 0.68 in the T-shaped group (P < .05). The VAS of patient satisfaction in the three-piece group (6.05 ± 1.29) was better than the T-shaped group (4.90 ± 1.05) on day 7 (P < .05).

CONCLUSION AND RELEVANCE

The three-piece tooth sectioning for HM3 removal was associated with shorter duration, slighter postoperative symptoms, and higher patient satisfaction and may be considered as a recommended practice for dentists.

Reliability of two difficulty indexes in predicting the surgical extraction difficulty of impacted mandibular third molars

Introduction: The aim of this study was to compare the reliability and the agreement of the Pederson and Pernambuco difficulty indexes in predicting the surgical extraction difficulty of the impacted mandibular third molars. Materials and methods: A prospective observational cohort study was conducted on 83 patients who had undergone surgical removal of impacted mandibular third molar. The difficulty of extraction was determined preoperatively according to the total scores obtained from the Pederson and Pernambuco difficulty indexes, the operative difficulty was determined by the surgical technique and the duration of extraction. The accuracy of prediction of the surgical difficulty and the degree of agreement of the two indexes were calculated. Results: The accuracy of Pederson and Pernambuco indexes in predicting the operative difficulty measured by duration of surgery was 36.1% and 55.4% respectively, and with operative difficulty measured by the technique was 21.7% and 37.3% respectively with statistically significant differences. The agreement between the 2 indexes was poor. Conclusion: Both indexes were limited in predicting the surgical difficulty of impacted mandibular third molars although the Pernambuco index was better than the Pederson index and the agreement between the two indexes was poor.

3D-printed titanium surgical guides for extraction of horizontally impacted lower third molars

OBJECTIVES

This prospective study introduced a digitally designed sectioning guide and evaluated its feasibility for the extraction of horizontally impacted lower third molars.

MATERIALS AND METHODS

This study included 38 horizontally impacted lower third molars, randomly divided into experimental and control groups. The teeth were extracted using a 3D-printed titanium surgical guide in the experimental group; free-hand extractions were performed in the control group. The surgical duration, tooth sectioning duration, cortical bone perforation, and postoperative complications, including pain, swelling, trismus, dry socket, infection, and hemorrhage, were evaluated.

RESULTS

Although not statistically significant, guided surgery tended to reduce the number of tooth sectioning steps compared to free-hand extractions. There were no cases of cortical bone perforation in the experimental group. Although the surgical duration was greater in the experimental group (p < 0.05), there were no differences in postoperative pain, swelling, and trismus. There were no cases of postoperative infection and hemorrhage in either group.

CONCLUSIONS

3D-printed titanium surgical guides had superior accuracy and safety compared to free-hand surgery. Further studies with larger sample sizes are required to verify these findings.

CLINICAL RELEVANCE

The template improved the safety of tooth sectioning during impacted lower third molar surgery and resulted in a more predictable extraction. The narrow sectioning groove could fit comfortably with hypertrophic soft tissues in the posterior mandible.

Prevalence of and risk factors for postoperative complications after lower third molar extraction: A multicenter prospective observational study in Japan

Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient's background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040-1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333-3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050-2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079-6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574-4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction.

Retrospective evaluation of sensory neuropathies after extraction of mandibular third molars with confirmed "high-risk" features on cone beam computed topography scans

OBJECTIVES

The objective of this study was to identify the incidence of inferior alveolar nerve (IAN) injury after extraction of mandibular third molars with confirmed "high-risk" features on cone beam computed topography scans and establish any risk factors that significantly increase the chances of sustaining an IAN injury.

STUDY DESIGN

This study is a retrospective analysis of outcomes after surgical extraction of 500 mandibular third molars over a 5-year period. All teeth showed signs of contact with or compression of the IAN on cone beam computed topography scans.

RESULTS

The overall incidence of IAN injury was 6.6%, with permanent neuropathies accounting for 1.8% within this high-risk cohort. Statistically significant factors shown to increase the risk of nerve injury included increasing age (P = .002), compression of the nerve evident on cone beam computed topography scan (P = .005), and buccal or interradicular position of the nerve (P = .042).

CONCLUSIONS

Results indicate a low incidence of IAN injury, particularly given the high-risk nature of all teeth that were extracted. It highlights the benefits of cone beam computed topography scans in surgical planning. These data are an important contribution to the existing literature and valuable in the consent procedure for patients undergoing surgical removal of mandibular third molars in contact with the IAN.

A Prospective Observational Study on the Variables Affecting the Risk of Inferior Alveolar Nerve Damage During Lower Third Molar Surgery With Nerve/Root Proximity

PURPOSE

The present study aimed to evaluate which factors were statistically associated with a greater probability of inferior alveolar nerve (IAN) damage during lower third molar surgery.

METHODS

A prospective observational study was performed at the Oral Surgery Unit of the Umberto I Hospital on 92 patients who underwent surgical extraction of a lower third molar that was radiographically overlapped with the mandibular canal. All surgeries were performed by the same expert surgeon. A principal component analysis and the exact 2-tailed Fisher exact test were used.

RESULTS

Temporary IAN damage occurred in 10 cases (10.9%). Symptoms lasted from 18 to 180 days (73 ± 49.15). IAN damage was more frequent in difficult and long-lasting surgeries, in the presence of many risk factors and in patients with a reduced maximum mouth opening.

CONCLUSION

Such factors should be accurately evaluated before surgery to assess and discuss the overall surgical risk of IAN damage with the patient especially when they are over the maximum limit of their significant variability range found in the present study, that is, >12 for difficulty index, >2 for number of orthopantomography risk markers and <3.7 cm for maximum mouth opening.

Surgical techniques for the removal of mandibular wisdom teeth

BACKGROUND

Pathology relating to mandibular wisdom teeth is a frequent presentation to oral and maxillofacial surgeons, and surgical removal of mandibular wisdom teeth is a common operation. The indications for surgical removal of these teeth are alleviation of local pain, swelling and trismus, and also the prevention of spread of infection that may occasionally threaten life. Surgery is commonly associated with short-term postoperative pain, swelling and trismus. Less frequently, infection, dry socket (alveolar osteitis) and trigeminal nerve injuries may occur. This review focuses on the optimal methods in order to improve patient experience and minimise postoperative morbidity.

OBJECTIVES

To compare the relative benefits and risks of different techniques for surgical removal of mandibular wisdom teeth.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health Trials Register (to 8 July 2019), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library; 2019, Issue 6), MEDLINE Ovid (1946 to 8 July 2019), and Embase Ovid (1980 to 8 July 2019). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. We placed no restrictions on the language or date of publication.

SELECTION CRITERIA

Randomised controlled trials comparing different surgical techniques for the removal of mandibular wisdom teeth.

DATA COLLECTION AND ANALYSIS

Three review authors were involved in assessing the relevance of identified studies, evaluated the risk of bias in included studies and extracted data. We used risk ratios (RRs) for dichotomous data in parallel-group trials (or Peto odds ratios if the event rate was low), odds ratios (ORs) for dichotomous data in cross-over or split-mouth studies, and mean differences (MDs) for continuous data. We took into account the pairing of the split-mouth studies in our analyses, and combined parallel-group and split-mouth studies using the generic inverse-variance method. We used the fixed-effect model for three studies or fewer, and random-effects model for more than three studies.

MAIN RESULTS

We included 62 trials with 4643 participants. Several of the trials excluded individuals who were not in excellent health. We assessed 33 of the studies (53%) as being at high risk of bias and 29 as unclear. We report results for our primary outcomes below. Comparisons of different suturing techniques and of drain versus no drain did not report any of our primary outcomes. No studies provided useable data for any of our primary outcomes in relation to coronectomy. There is insufficient evidence to determine whether envelope or triangular flap designs led to more alveolar osteitis (OR 0.33, 95% confidence interval (CI) 0.09 to 1.23; 5 studies; low-certainty evidence), wound infection (OR 0.29, 95% CI 0.04 to 2.06; 2 studies; low-certainty evidence), or permanent altered tongue sensation (Peto OR 4.48, 95% CI 0.07 to 286.49; 1 study; very low-certainty evidence). In terms of other adverse effects, two studies reported wound dehiscence at up to 30 days after surgery, but found no difference in risk between interventions. There is insufficient evidence to determine whether the use of a lingual retractor affected the risk of permanent altered sensation compared to not using one (Peto OR 0.14, 95% CI 0.00 to 6.82; 1 study; very low-certainty evidence). None of our other primary outcomes were reported by studies included in this comparison. There is insufficient evidence to determine whether lingual split with chisel is better than a surgical hand-piece for bone removal in terms of wound infection (OR 1.00, 95% CI 0.31 to 3.21; 1 study; very low-certainty evidence). Alveolar osteitis, permanent altered sensation, and other adverse effects were not reported. There is insufficient evidence to determine whether there is any difference in alveolar osteitis according to irrigation method (mechanical versus manual: RR 0.33, 95% CI 0.01 to 8.09; 1 study) or irrigation volume (high versus low; RR 0.52, 95% CI 0.27 to 1.02; 1 study), or whether there is any difference in postoperative infection according to irrigation method (mechanical versus manual: RR 0.50, 95% CI 0.05 to 5.43; 1 study) or irrigation volume (low versus high; RR 0.17, 95% CI 0.02 to 1.37; 1 study) (all very low-certainty evidence). These studies did not report permanent altered sensation and adverse effects. There is insufficient evidence to determine whether primary or secondary wound closure led to more alveolar osteitis (RR 0.99, 95% CI 0.41 to 2.40; 3 studies; low-certainty evidence), wound infection (RR 4.77, 95% CI 0.24 to 96.34; 1 study; very low-certainty evidence), or adverse effects (bleeding) (RR 0.41, 95% CI 0.11 to 1.47; 1 study; very low-certainty evidence). These studies did not report permanent sensation changes. Placing platelet rich plasma (PRP) or platelet rich fibrin (PRF) in sockets may reduce the incidence of alveolar osteitis (OR 0.39, 95% CI 0.22 to 0.67; 2 studies), but the evidence is of low certainty. Our other primary outcomes were not reported.

AUTHORS' CONCLUSIONS

In this 2020 update, we added 27 new studies to the original 35 in the 2014 review. Unfortunately, even with the addition of these studies, we have been unable to draw many meaningful conclusions. The small number of trials evaluating each comparison and reporting our primary outcomes, along with methodological biases in the included trials, means that the body of evidence for each of the nine comparisons evaluated is of low or very low certainty. Participant populations in the trials may not be representative of the general population, or even the population undergoing third molar surgery. Many trials excluded individuals who were not in good health, and several excluded those with active infection or who had deep impactions of their third molars. Consequently, we are unable to make firm recommendations to surgeons to inform their techniques for removal of mandibular third molars. The evidence is uncertain, though we note that there is some limited evidence that placing PRP or PRF in sockets may reduce the incidence of dry socket. The evidence provided in this review may be used as a guide for surgeons when selecting and refining their surgical techniques. Ongoing studies may allow us to provide more definitive conclusions in the future.

Development of a New Index to Assess the Difficulty Level of Surgical Removal of Impacted Mandibular Third Molars in an Asian Population

PURPOSE

This study aimed to develop a straightforward and accurate index of impacted third molar removal difficulty through analyzing various factors to assess the difficulty level of impacted mandibular third molar (IMTM) extraction.

MATERIALS AND METHODS

This prospective cohort study included 203 patients who required IMTM extraction. All patients were selected using the preset selection criteria. The present study assessed operation difficulty with operating time. A mathematical model and regression analysis were performed to explore 6 main factors (age, number of roots, degree of bone impaction, shape of roots, and impaction angle and its relation). Appropriate correction coefficients were obtained to formulate a new IMTM removal difficulty predictive index. Consistency of the κ value was checked to evaluate performance.

RESULTS

Degree of bone impaction had the highest correlation coefficient (0.576), followed by shape of roots (0.359), and the lowest correlation coefficient was for number of roots. The Pederson index for these 203 patients showed that 75, 76, and 52 patients had low, moderate, and high difficulty levels, respectively, whereas the new index categorized 78, 85, and 40 patients as having low, moderate, and high difficulty. Comparison of the Pederson index and new index with operating time showed κ agreements of 65.30 and 77.9% (P < .01), suggesting that the prediction results of the new index are more objective and accurate.

CONCLUSION

The newly proposed index is straightforward and efficient and exhibited promising results in κ agreement. Because of its straightforward nature, it is better suited for Chinese public hospitals with a large volume of patients who require alveolar surgery. The detection of predictor variables could be useful for graduate students, professionals, and general dental practitioners contemplating IMTM removal to assess the difficulty level of IMTM extraction.

Effect of One-Suture and Sutureless Techniques on Postoperative Healing After Third Molar Surgery

PURPOSE

The wound closure technique for lower third molar surgery (LTMS) is an operative factor that influences wound healing and the occurrence of early postoperative complications. The present study investigated 2 closure techniques (partial closure using 1 suture and the suture-less technique) after use of a modified buccal envelope flap for LTMS.

MATERIALS AND METHODS

We performed a prospective, randomized, double-blind, split-mouth, controlled trial. Partial closure using 1 suture was compared with closure using the sutureless technique. The surgical sites were divided into 2 groups, group A (1 suture) and group B (sutureless). Each patient received both treatments at the same surgery. During the first postoperative week, all patients were asked to daily assess pain, facial swelling, and bleeding using self-assessment scales. All patients attended the follow-up appointment at 1 week to objectively assess facial swelling and wound healing and at 1 month to assess wound healing. An analysis of data was performed using the statistical package SPSS Statistics, version 24 (IBM Corp, Armonk, NY). A P value ≤ .05 was accepted as statistically significant.

RESULTS

A total of 37 patients with bilateral impacted third molars of similar surgical difficulty were recruited. Of the 37 patients, 34 successfully completed the study. The results showed a statistically significant difference between the 2 techniques in postoperative pain at days 5 (P = .046) and 6 (P = .034); socket healing at 1 week (P = .002) and 1 month (P = .014), and soft tissue healing at 1 week (P = .016).

CONCLUSION

We found the 1-suture technique for LTMS to be superior to the sutureless technique in the reduction of postoperative pain and improving wound healing during the early postoperative period. We found no difference between the 2 techniques in the reduction of postoperative swelling.

Radiographic features of anatomic relationship between impacted third molar and inferior alveolar canal on coronal CBCT images: risk factors for nerve injury after tooth extraction

INTRODUCTION

The present study was aimed to identify the radiographic signs between impacted third molar root and inferior alveolar canal (IAC) on cone-beam CT (CBCT) images as risk factors and prognostic predictors associated with inferior alveolar nerve (IAN) damage following tooth removal.

MATERIAL AND METHODS

A retrospective clinical study was performed involving 136 patients with 257 impacted lower third molars from January 2013 to December 2014. The neurosensory function of the lower lip and chin was subjectively evaluated and assessed by neurosensory tests before and after surgery. The preoperative CBCT data were retrieved and analyzed to identify the radiographic signs associated with postoperative IAN injury.

RESULTS

The overall incidence of IAN injury in our patient cohort was 13.2%. Multiple radiographic features on coronal CBCT images including contact between IAC and root, IAC position relative to root, IAC shape and cortication status were found to be significantly associated with IAN damage (p < 0.05, χ² test). Furthermore, buccolingual position, teardrop/dumbbell shape and cortication status of IAC were identified as independent prognostic predictors for IAN damage.

CONCLUSIONS

Our findings indicate that radiographic signs including direct contact between IAC and root, buccal/lingual IAC position relative to root, teardrop/dumbbell shape and cortication absence of the IAC on presurgical CBCT images are associated with high risk of IAN injury and postoperative neurosensory disturbance.