Importance of Clinical and Radiological Parameters in Assessment of Surgical Difficulty in Removal of Impacted Mandibular 3rd Molars: A New Index

Asymmetric outcomes in bilateral maxillary impacted tooth extractions: A case report

BACKGROUND

The extraction of maxillary impacted teeth is a common procedure in oral surgery, frequently complicated by oroantral communications. For less-experienced clinicians, accurately assessing the difficulty and associated risks of maxillary third molar extractions remain a significant challenge.

CASE SUMMARY

We present a case involving disparate outcomes following bilateral extraction of maxillary third molars. Using cone-beam computed tomography and three-dimensional software, we conducted a digital assessment of the factors contributing to extraction difficulty and risk, controlling for potential confounders. Key variables analyzed included alveolar bone volume, bone quality, crown-root angulation, and maxillary sinus mucosal thickness. Additionally, we introduce the novel concept of "tegmen bone" to quantitatively evaluate the bone mass between the teeth and the maxillary sinus. This unique case, with differing outcomes on opposite sides of the same patient, provided an opportunity to minimize extraneous variables and focus on the local anatomical factors influencing the procedures, thereby improving the precision of our analysis.

CONCLUSION

This case highlights the potential utility of predictive analysis in guiding the management of complex tooth extractions.

Estimating the Extraction Time of an Upper Third Molar: Proposal and Validation of Results

Background: Numerous studies in the literature have aimed to evaluate the difficulty level of removing third molars. However, most of these studies have focused on the lower third molars, which can lead to complications. There is a lack of a method to determine the complexity of upper third molar extraction. Therefore, this study's objective was to develop an equation using multiple linear regression to estimate the extraction time of an upper third molar based on its complexity. Methods: This study involved patients enrolled in the Master of Oral Surgery program at the University of Seville. To determine their relationship with surgical time, the researchers analyzed various factors, such as depth, root morphology, and the need for odontosection. They then validated their findings by studying patients treated at Palmaplanas Hospital in Mallorca. Results: The cohort analysis from the University of Seville revealed significant associations between surgical time and the identified factors. A regression equation design was performed to predict the total duration of surgical intervention for wisdom teeth extraction. This equation incorporates several independent variables, represented by Xi, together with a constant term, C, and the corresponding coefficients, Bi, which weight the impact of each variable on the intervention time. The results are as follows: -0.312 (spatial relationship), 0.651 (depth), -0.443 (bone and mucosa integrity), 0.214 (roots), -0.745 (ostectomy), 0.713 (odontosection), and -0.426 (suture). Upon application of the statistical methodology to the Palmaplanas Hospital cohort, a regression coefficient of 0.770 was determined. This indicates a strong correlation between the input data and the estimated surgical time. Conclusions: In conclusion, the proposed formula demonstrates notable validity in predicting the surgical time required to extract upper third molars.

Proposal and Validation of a New Index to Assess the Difficulty of Lower Third Molar Extraction

There is no current consensus on the parameters that determine the difficulty of mandibular third molar extraction in terms of the time required, which is essential to prevent complications and optimize the time of the intervention. This study aims to obtain, using the mathematical method of multiple linear regression, an equation that allows estimating the extraction time of a lower third molar according to its complexity, as well as to validate this equation in a sample of external wisdom teeth.

METHODS

A prospective cohort study on a sample of patients of the Master of Oral Surgery of the University of Seville in which multiple linear regression coefficients were calculated with a subsequent validation study of the results in the sample of patients operated in the Hospital Palmaplanas of Mallorca.

RESULTS

The regression line obtained after applying the statistical methodology to the cohort of patients from the University of Seville obtained significant dependent variables such as depth, roots, and odontosection. Once applied to the cohort of patients from the Palmaplanas Hospital in Mallorca, a regression coefficient was obtained between the data received and the estimated 0.770.

CONCLUSIONS

The formula proposed in this article presents significant validity in the prediction of the surgical time of extraction of the lower third molars included.

Perceived surgical difficulty of mandibular third molar extraction. A comparative cross-sectional study of dentists with postgraduate qualification in oral surgery and maxillofacial surgeons in a Spanish subpopulation

BACKGROUND

Mandibular third molar (MTM) extraction is one of the most frequently performed surgeries in the oral cavity. Establishing the level of surgical difficulty pre-operatively is an essential step to ensure correct treatment planning. In Spain, MTM extraction - especially in cases presenting greater difficulty - is normally performed by doctors specializing in oral and maxillofacial surgery, or by dentists with postgraduate qualifications in oral surgery. The present work set out to analyze the extent to which perceptions of surgical difficulty of the said intervention vary in relation to professional training.

MATERIAL AND METHODS

This cross-sectional, descriptive, observational study took the form of a survey. Using a visual analog scale (VAS), participants evaluated both the perceived difficulty of 30 cases of MTM extraction described by means of digital panoramic radiographs and the perceived difficulty deriving from a series of factors conditioning MTM extraction. The results underwent statistical analysis with SPSS Statistics 28.0 software. Non-parametric tests (Mann Whitney test for independent samples and the Kruskal-Wallis test) were applied.

RESULTS

A total of 213 surveys were available for analysis. Both groups awarded the greatest importance to clinical experience, followed by anatomical and radiographic factors, root morphology obtaining the highest score among anatomical factors (9.01±1.42), while proximity of the MTM to the inferior alveolar nerve was regarded as the least important anatomical factor (8.11±2.54). Significant differences were only found for patient age, whereby maxillofacial surgeons awarded this factor more importance than dentists.

CONCLUSIONS

The different training received by dentists specialized in oral surgery and maxillofacial surgeons did not influence either perceptions of surgical difficulty of MTM extraction, or opinions as to the factors influencing surgical difficulty.

Mandibular third molar extraction: perceived surgical difficulty in relation to professional training

BACKGROUND

Establishing the level of surgical difficulty pre-operatively is an essential step in ensuring correct treatment planning. This study set out to determine whether the knowledge and experience acquired by dentists who had received different levels of training influenced, firstly, the perceived levels of difficulty of a variety of cases of mandibular third molar (MTM) extraction and, secondly, the perceived difficulty deriving from a series of factors (patient-related factors, anatomical and radiographic factors, operative factors).

METHODS

This cross-sectional, descriptive, observational study took the form of a survey. Using a visual analog scale (VAS), participants evaluated both the perceived difficulty of 30 cases of MTM extraction described by means of digital panoramic radiographs and the perceived difficulty deriving from a series of factors conditioning MTM extraction. The results underwent statistical analysis with SPSS Statistics 28.0 software. Non-parametric tests (Mann Whitney test for independent samples and the Kruskal-Wallis test) were applied.

RESULTS

A total of 389 surveys were available for analysis. Dental practioners with no surgical training saw the intervention as presenting greater difficulty. Professionals with postgraduate training in oral surgery considered patient-related factors more important than operative factors, in contrast to dentists who had not received oral surgery training.

CONCLUSIONS

Dental training has a signficant influence on the perceived difficulty of MTM extraction and also affects opinions about which factors have greater or lesser influence on surgical difficulty.

Characterizations of three-dimensional root morphology and topological location of mandibular third molars by cone-beam computed tomography

PURPOSE

This study aimed to delineate three-dimensional (3D) root morphology and topological locations of mandibular third molars (MTMs) by cone-beam computed tomography (CBCT) in a Chinese adult dental population.

METHODS

Adult patients with MTMs were retrospectively screened based on CBCT images at our institution between January 2018 and December 2019. Root morphology and spatial locations of these teeth were defined based on CBCT 3D images. Potential associations with epidemiological and clinical/radiological parameters were analyzed using Chi-square or Fisher exact test. Two-tailed P values less than 0.05 were considered statistically significant.

RESULTS

A total number of 2680 eligible patients (male/female:0.74; 35 ± 10 years old) with 4180 MTMs were enrolled. The majority of MTMs had 2 roots 3064 (73.30%), followed by 800 (19.14%) 1 root, 302 (7.22%) 3 roots, and 14 (0.33%) 4 roots. More than half of one-rooted MTMs were convergent, followed by club-shaped and C-shaped. Among MTMs with 2 roots, 2860 (93.34%) were M-D (mesio-distal) types. Most MTMs with 3 roots were M-2D (one root in mesial, two roots in distal) types, followed by 2M-D (two roots in mesial, one root in distal) types, and B-2L (one root in buccal, two roots in lingual) types. The presence of root configurations was significantly associated with the angulation, depth, and width classification in two-rooted MTMs (P < 0.05).

CONCLUSIONS

Although the morphology and spatial locations of MTMs vary greatly, our results from a large dental population reconfirm that most MTMs have two roots with mesial-distal type of spatial distribution.

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.

Application of a Cone-Beam Computed Tomography-Based Index for Evaluating Surgical Sites Prior to Sinus Lift Procedures-A Pilot Study

OBJECTIVES

Radiography-based indices can help surgeons perform detailed examinations of the surgical site and predict the surgical difficulty of cases. We aimed to develop and validate a novel CBCT-based index that can predict the surgical difficulty of sinus-augmentation procedures.

MATERIALS AND METHODS

In the first stage, five experienced dental specialists performed a review of the literature and closed group discussions and designed the novel index. In the next stage, the index was validated. CBCT scans of 30 patients scheduled for sinus-augmentation procedures were evaluated and assigned presurgical CBCT evaluation scores (PSCESs) by five examiners. Subsequently, one oral surgeon performed sinus augmentation using the lateral antrostomy technique and assigned surgical difficulty scores (SDSs) to each of the 30 cases along with 2 observers. The PSCESs and SDSs were statistically analysed to determine the interrater reliability and validity of the index.

RESULTS

The interrater agreement of the PSCES among the five presurgical evaluators was 0.85. The PSCES of the five evaluators had highly significant correlation (P < 0.001, r = 0.68 to 0.76) with the SDS. Regression analysis revealed that for every unit increase in the PSCES, there is 0.46 to 0.57 increase in the SDS value.

CONCLUSION

The results of this pilot study revealed that a novel CBCT-based index can be used as a reliable tool for predicting the surgical difficulty of sinus-augmentation procedures. However, the novel index needs to be tested on a larger sample of patients and evaluators for a more concrete validity and reliability.

Correlation of Variables for WHARFE Assessment and Pederson Difficulty Index for Impacted Mandibular Third Molar Surgery-A Prospective Clinical Study

Objectives

To assess the correlation of factors of WHARFE assessment and Pederson difficulty index for impacted mandibular third molar surgery.

Study Design

A comparative study of difficult factors utilizing Pederson WHARFE and WAR lines was performed involving patients undergoing surgical removal of mandibular third molars for 100 such teeth.

Results

The Spearman's rho correlation run to determine the relationship between Pederson difficulty index and WHARFE assessment values showed a strong, positive monotonic correlation at the 0.05 level (2-tailed; rs = 0.242, n = 100, p = 0.015 < 0.05).

Conclusion

The study has revealed WHARFE assessment to be a more reliable and consistent measure for the radiological evaluation of surgical difficulty over the contemporary Pederson difficulty index.

Review of Difficulty Indices for Removal of Impacted Third Molars and a New Classification of Difficulty Indices

BACKGROUND

A number of efforts have been made to establish a reliable assessment model for the surgical removal of impacted third molars. Although many such models have been proposed, none is considered universally applicable, and controversy remains. The earlier attempts were based exclusively on radiographic variables, whereas recent evidence is associated with nonradiographic and demographic variables.

PURPOSE

This article aimed to prepare review of the relevant literature to summarize the important indices given till date, tabulating only new indices as old indices are mentioned in almost all text books, their merits and demerits and their specificity and sensitivity (if assessed in the literature). In addition to it, authors also aimed to introduce a new descriptive classification of all indices based on pre- and postoperative assessment and further classify based on clinical, radiographic and demographic factors, surgical technique and time. This article will be of academic and practical help for residents and clinicians.

METHOD

A literature search was conducted in Medline, PubMed, Google Scholar, Science Direct and Cochrane electronic database with keywords-impacted mandibular third molar, difficulty indices, validity of, sensitivity, specificity. No publication year limit was used. The abstracts of the articles were retrieved, reviewed and sorted based on the following inclusion and exclusion criteria. Articles which include a new index, validate difficulty index, compare two or more difficulty indices, specificity and sensitivity of particular index are included. Duplicate articles, articles on complication, flap design, drug study, radiographic relation of inferior alveolar nerve, suturing, classification, only assessing factor affecting difficulty of third molar surgery are not included.

RESULTS

Total 39 (36 articles + 3 books) are included. A total of 20 individual indices were found in the literature; each has been described in brief in this review. These indices are also listed in chronological order with their specificity and sensitivity if accessed in the literature.

CONCLUSION

There is a definite need to derive and validate an user-friendly index that could be used for preoperative prediction of difficulty. To the best of our knowledge, this review including all indices till date and classification proposed is the first on this subject.

Patient, radiological, and operative factors associated with surgical difficulty in the extraction of third molars: a systematic review

The aim of this systematic review was to determine the patient, radiological, and operative variables associated with surgical difficulty in the extraction of third molars, according to a visual analogue scale completed by the surgeon, operative time, or surgical technique. Searches of the PubMed (MEDLINE), Scopus, and Cochrane Library databases were conducted by two independent reviewers. Randomized and non-randomized clinical trials and prospective cohort studies evaluating surgical difficulty in the extraction of impacted mandibular or maxillary third molars according to patient, radiological, and operative variables were included. The full texts of 21 of the 859 articles initially retrieved were analysed, and 15 articles were included in the final systematic review. All 15 reported prospective cohort studies. The following variables were found to be on the spectrum of highly difficult or complex cases: older patient age and being overweight (patient variables), surgeons with little experience and the use of complex surgical techniques requiring tooth sectioning linked to hard tissue impaction (operative variables), and adverse radiological factors such as deep impaction, unfavourable angulation and root morphology, and a close relationship with the second molar, maxillary sinus, or the inferior alveolar nerve canal (radiological variables).

Does Mandibular Gonial Angle Predict Difficulty of Mandibular Third Molar Removal?

PURPOSE

Predicting the difficulty of impacted mandibular third molar (IM3M) removal remains a controversial issue because many variables have been associated with increased operation time. Thus, the main objective of this study was to assess the influence of the gonial angle on the surgical difficulty of IM3M extraction.

PATIENTS AND METHODS

A prospective cohort study of patients requiring IM3M removal was conducted. The gonial angle measured with a goniometer was considered the primary predictor variable. The primary outcome variable was operation time. Difficulty also was recorded by surgeons using a 100-mm visual analog scale (VAS). Postoperative complications (pain, swelling, and trismus at 48 hours and 7 days) were registered as secondary outcome variables. A descriptive bivariate statistical analysis, Pearson correlations and scatter plots, and an explanatory multiple linear regression model were performed. Significance was set at P < .05.

RESULTS

The sample comprised 60 participants (17 men and 43 women) with a mean age of 25.2 years (standard deviation, 7.1 years). No significant correlations were found between the gonial angle and operation time, VAS difficulty score, and postoperative complications. Regression analysis confirmed this lack of effect of the gonial angle. The operation time was significantly affected by surgical experience (P = .016) and patient age (P = .009), whereas the 100-mm VAS difficulty score was only related to surgical experience (P = .001).

CONCLUSIONS

The gonial angle is not related to the surgical difficulty of IM3M removal. Moreover, this variable is not associated with the occurrence of postoperative complications. According to the findings in this cohort, surgical experience and patient age are the only variables significantly related to increased operation time.

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.

Pernambuco index: predictability of the complexity of surgery for impacted lower third molars

This study aimed to develop and validate an index of surgical difficulty for the removal of impacted lower third molars. The study was performed in two steps. The first was a cross-sectional analysis of clinical, demographic, and radiographic variables collected from patients undergoing the removal of an impacted lower third molar between 2008 and 2012. The second step was a prospective cohort study involving the same surgical procedures to validate the index; this was performed between 2013 and 2016. Univariate regression analysis was applied, followed by multiple linear regression analysis. A total of 753 surgical procedures were analyzed in the first stage, which led to the identification of the most important variables and their levels of significance. The index was then applied to 280 surgical procedures. The preoperative difficulty was in concordance with the index results in all cases. Among cases with a low level of difficulty, 93.1% had been indexed as low difficulty; likewise, among cases with a high level of difficulty, there was 87.9% concordance with the index. With the use of reference statistics in the development and quality assurance processes, this validated index has proven to be a reliable and easily applicable instrument, with high sensitivity, specificity, and accuracy.

Predictive factors of difficulty in lower third molar extraction: A prospective cohort study

Background

Several publications have measured the difficulty of third molar removal, trying to establish the main risk factors, however several important preoperative and intraoperative variables are overlooked.

Material and Methods

A prospective cohort study comprising a total of 130 consecutive lower third molar extractions was performed. The outcome variables used to measure the difficulty of the extraction were operation time and a 100mm visual analogue scale filled by the surgeon at the end of the surgical procedure. The predictors were divided into 4 different groups (demographic, anatomic, radiographic and operative variables). A descriptive, bivariate and multivariate analysis of the data was performed.

Results

Patients’ weight, the presence of bulbous roots, the need to perform crown and root sectioning of the lower third molar and Pell and Gregory 123 classification significantly influenced both outcome variables (p< 0.05).

Conclusions

Certain anatomical, radiological and operative variables appear to be important factors in the assessment of surgical difficulty in the extraction of lower third molars.

Key words:Third molar, surgical extraction, surgical difficulty.

Which factors are associated with difficult surgical extraction of impacted lower third molars?

Objectives

The aim of this retrospective study was to investigate factors associated with increased difficulty in the surgical extraction of impacted lower third molars and to improve identification of difficult cases.

Materials and Methods

A total of 680 patients who required 762 surgical extractions of impacted lower third molars from 2009 to 2014 were enrolled in the study. Demographic factors, clinical factors, radiographic factors, surgical extraction difficulty, and presumed causes of difficulty were collected. Data were statistically analyzed using IBM SPSS Statistics version 23.

Results

Age, sex, depth of impaction, and blurred radiographic image influenced difficulty in surgical extraction. The position of the impacted tooth influenced surgical difficulty, especially when it was accompanied by other factors.

Conclusion

It is challenging to design a reliable and practical instrument to predict difficulty in surgical extraction of impacted lower third molars. To identify very difficult cases, root investigation using computed tomography is advised when impacted tooth position suggests difficult extraction.