- Email: [email protected]
Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial
YIJOM-3348; No of Pages 4
Int. J. Oral Maxillofac. Surg. 2016; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2016.01.007, available online at http://www.sciencedirect.com
Randomized Controlled Trial Trauma
Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial
Z. McNamara1, G. Findlay1, P. O’Rourke2, M. Batstone1 1
Department of Oral and Maxillofacial Surgery, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia; 2 Statistics Unit, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Z. McNamara, G. Findlay, P. O’Rourke, M. Batstone: Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial. Int. J. Oral Maxillofac. Surg. 2016; xxx: xxx–xxx. # 2016 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.
Abstract. The treatment dilemma provided by asymptomatic third molars in mandibular angle fractures remains controversial. This prospective randomized controlled trial was undertaken to determine whether there is an advantage to extraction or retention of the third molar whilst repairing a mandibular angle fracture. Sixty-four patients were allocated randomly to the two treatment groups. All underwent open reduction and internal fixation (ORIF) with standard postoperative care. The primary outcome measure was uncomplicated fracture healing. Secondary measures were surgical duration, malocclusion, wound healing, nerve injury, and return to theatre. All patients had uncomplicated fracture healing. The incidence of nerve injury was 16% for the retention group compared with 39% for the removal group (P = 0.038). The average operating time for ORIF and third molar retention cases was 58.5 min and for ORIF and third molar removal cases was 66.3 min (P = 0.26). There was no statistically significant difference between groups for wound healing, occlusion outcomes, or return to theatre. Given the additional risk of nerve injury and the additional operating time required for removal of a third molar, in the absence of an absolute indicator for removal of the third molar, it appears justifiable to advise retaining the tooth in the line of a mandibular angle fracture.
Accepted for publication 14 January 2016
The treatment of mandibular angle fractures has evolved over the years from closed reduction with a period of intermaxillary fixation, to open reduction with internal fixation (ORIF).1 One aspect of the ORIF procedure that remains
85% contained a third molar.2 Historically, extraction of the tooth in the fracture line was advocated, as this was thought to decrease the risk of infection and the need for removal of the wisdom tooth and plating at a later date.3,4 However, over
0901-5027/000001+04
controversial at present is the management of an asymptomatic wisdom tooth in the line of an angle fracture. This issue is important as this treatment dilemma is common. A study by Ellis showed that out of 402 angle fractures,
Key words: randomized controlled trial mandibular angle fractures; internal fixation; third molars.
# 2016 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
YIJOM-3348; No of Pages 4
2
McNamara et al.
the years this view has been challenged with the counter-argument that extraction of the third molar risks loss of bone, making reduction and plating more difficult, increases the surgical time, and increases the risk to the inferior dental nerve. At present there is conflicting information in the literature concerning the question of extracting or retaining an asymptomatic third molar in the line of a mandibular angle fracture, with no prospective randomized controlled trials conducted.2,5–12 Thus clinicians have to use their best judgement rather than evidencebased medicine in weighing the benefits and risks of removing a third molar in the line of an angle fracture against the benefits and risks of retaining it.2 The aim of this study was to compare the outcomes of fractures of the mandibular angle with random allocation to removal or retention of the third molar tooth. Methods Trial design
A prospective randomized controlled trial was performed. There were no changes to the methods after trial commencement. All patients presenting to the maxillofacial unit with a mandibular angle fracture requiring ORIF (Table 1) and who were 18 years of age or older were considered for inclusion in the study. Patients who could not give informed consent and patients with absolute indicators for the removal of third molars in angle fractures (Table 2) were excluded. Randomization was accomplished by sealed envelopes containing allocation to one of the two study groups. Sixty-four patients gave consent and were deemed eligible for the trial.
Table 1. Indicators for open reduction and fixation of a mandibular angle fracture. 1 Unfavourable fracture 2 Inability to obtain adequate occlusion by closed techniques 3 Infection (peri-apical/pericoronitis) 4 Fracture of tooth/roots
Table 2. Absolute indicators for removal of third molars.12 1 Caries 2 Mobile tooth 3 Infection (peri-apical/pericoronitis) 4 Fracture of tooth/roots 5 Pathology associated with third molar 6 Preventing adequate fracture reduction
Ethical approval for the study was granted by the necessary human research and ethics committee. Participants
Patients were assessed on presentation and standard imaging was obtained (panoramic radiographs and postero-anterior mandible X-rays). Demographic data including age, sex, smoking status, diabetes, and indigenous ethnicity were documented. Examination findings related to post-trauma alveolar nerve function were also recorded. Randomization then occurred by the participant drawing one of two possible envelopes, indicating which arm of the trial they would be included in. Participants were not blinded to their allotted treatment.
Results Participant flow
Sixty-four patients were enrolled in the study. The randomization process allocated 31 patients to the retention group and 33 patients to the removal group. All allotted patients underwent treatment as per their group. Patient demographics (Table 3)
There was no statistically significant difference between the groups regarding sex (P = 0.19), mean age at injury (P = 0.78), or the average number of fractures treated (P = 0.56). Furthermore, there was no statistically significant difference between the groups regarding smoking status (P = 0.86), diabetic comorbidity (P = 1.00), or indigenous ethnicity (P = 0.28).
Surgical details
Surgery was performed under general anaesthesia predominantly by a maxillofacial surgeon (GF). If not the primary operator, the surgeon (GF) was present as an assistant. All angle fractures were secured with a single 2.0-mm miniplate via a combined transoral incision and transbuccal trocar. The fractured segments were approximated visually with the dentition held in occlusion by the assistant whilst fixation was applied. Resorbable sutures were utilized for wound closure. Standard clinical and radiographic postoperative follow-up was undertaken. Outcomes
The primary outcome measure was uncomplicated fracture healing. The secondary measures were wound issues (wound breakdown/infections/collections), operative duration, malocclusion, inferior dental nerve (IDN) injury, and return to theatre. Surgeons undertook each postoperative patient assessment, but they were not blinded to which group patients had been allocated. Patients who did not attend clinic review appointments were deemed to have had nil negative outcomes. Categorical data were summarized as frequencies, and comparisons across allocated groups were done by cross-tabulations and x2 tests for significance. Continuous variables were summarized as the mean and range, and comparisons between groups were done using the independent samples t-test or the Mann–Whitney U-test. All significance tests used a two-sided P-value of 0.05.
Primary outcome
The primary outcome measure was uncomplicated fracture healing. Each group, removal and retention, had one return to theatre for non-union. Both return cases had an uneventful postoperative recovery following the second surgery. Therefore all 64 cases had eventual complete fracture healing.
Secondary outcome measures (Table 4)
The average surgical time for retention cases was 58.5 min and for removal cases was 66.3 min; however this difference between the groups was not statistically significant (P = 0.26). All patients underwent X-ray postoperatively. Furthermore, all patients had at least one postoperative review. The follow-up period for the removal and retention groups was similar: follow-up ranged from 1 to 164 days (mean 27 days, median 12 days) in the removal group and from 1 to 164 days (mean 26 days, median 27 days) in the retention group (P = 0.49, Mann–Whitney U-test). With regard to wound issues, the removal group (9.1%) had a higher rate than the retention group (0%), but this difference between the groups was not statistically significant (P = 0.09). The incidence of malocclusion was similar in the retention group (12.9%) and removal group (12.1%) (P = 0.92). Importantly the incidence of IDN injury showed a significant difference (P = 0.038), with the retention group (16.1%) showing a lower incidence than the removal group (39.4%).
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
YIJOM-3348; No of Pages 4
Third molar removal/retention in angle fractures Table 3. Demographics of patients included in the study and average number of fractures treated. Study group Retention (n = 31)
Removal (n = 33)
30 1
29 4
23 18–46 1.71
23 18–44 1.79
Sex Male Female Age, years Mean Range Average number of fractures treated
P-value 0.19 0.78 0.56
Table 4. Secondary outcome measures. Study group Retention (n = 31) Surgical time, min Mean Range Wound issues, % Malocclusion, % IDN injury, %
58.5 14–109 0% 12.9% 16.1%
Removal (n = 33) 66.3 19–122 9.1% 12.1% 39.4%
P-value 0.26 0.09 0.92 0.038
IDN, inferior dental nerve.
Return to theatre occurred twice during this study. Each group, removal and retention, had one occurrence. In the retention case, the patient had continuing postoperative pain and a subsequent follow-up Xray showed a non-union of the angle fracture. For the removal case, the patient had an ongoing wound infection at the surgical site and a persistent malocclusion. A follow-up X-ray also showed non-union of the angle fracture. Both return cases had an uneventful postoperative recovery following the second surgery. Discussion
Randomization provided two groups with a similar composition in terms of sex, ethnicity, age, and smoking status. It was expected that this randomization would also result in similar levels of preoperative paresthesia. The same surgeon (GF) was present during all operative procedures thus removing one cause of bias. Following the surgery, both groups had a similar follow-up regimen and observation time period. It is believed that this process enabled a meaningful study of comparison between the two groups. Ellis previously reported a 19.5% infection rate when the tooth was present in the angle fracture as compared to 19.0% when the tooth was extracted.2 The results of the present study differ from those of that previous study. In the retention group, none of the 31 patients (0%) had postoperative wound issues, while in the removal group, three of the 33 patients (9.1%) had such issues. Although this did not reach
statistical significance (P = 0.09), a trend towards greater wound complications with third molar removal was seen in the present study. Importantly, a recent systematic review and meta-analysis also showed that there was no significant statistical difference between removing or retaining the tooth in the line of fracture with regard to the occurrence of postoperative infection.13 However it is important to note that this analysis included only three prospective trials, none of which were randomized. A previous non-randomized prospective trial conducted by Rai and Pradhan in India commented on the discrepancy in occlusion between the groups.14 They reported that the removal group (16.7%) had a higher occlusion discrepancy compared to the retention group (13.3%).14 Although the result was not statistically significant, they hypothesized that the removal of the third molar causes a loss of contact and continuity in the fracture, and thus more chances of displacement or collapse during fixation.14 The results of the present study regarding malocclusion in the two groups, although not significant, differed from their study. The present study showed a minimal difference between the groups: retention group 12.9% and removal group 12.1%. So perhaps the loss of contact and continuity in the fracture is less of a problem than hypothesized. It is acknowledged that direct comparison of studies from different units and countries is difficult, as the aetiology of fractures, socio-economic status of the
3
patients, patient compliance, quality of post-surgical care, and definitions of complications may vary. Several weaknesses of this study should be acknowledged. Firstly, neither the patient nor the operating surgeon nor the assessor was blinded to the treatment allocation. For several reasons this is impossible, but most notably the postoperative X-ray reveals a tooth socket or the presence of a tooth depending on allocation. Secondly, like most studies on facial trauma, patient return for follow-up was poor, which limits the validity of results, particularly long-term factors such as nerve recovery. Thirdly, some of the values measured may have achieved statistical significance had the study recruited more patients. For example, wound issues showed a trend towards increased problems in the removal group. Finally the principal surgeon (GF) is very experienced and thus it may not be possible to extrapolate the results achieved to other units. Importantly this prospective trial looked at the risk to the IDN when considering retaining or removing the third molar in an angle fracture. A statistically significant difference was found between the groups (P = 0.038). Perhaps understandably, patients in the removal group reported a higher incidence of decreased sensation in the distribution of the IDN (39.4% vs. 16.1% in the retained group). During removal of the third molar, the displacement of the fracture fragments during the procedure and extra time taken to complete the procedure, with subsequent swelling, increase the patient risk when compared to the risk in the retained group patients. Given the additional risk of nerve injury and the additional operating time required for removal of a third molar, in the absence of an absolute indicator for removal of the third molar the authors would advise the retaining of an asymptomatic wisdom tooth in the line of a mandibular angle fracture. Funding
None. Competing interests
None. Ethical approval
Ethical approval for the study was granted by the Human Research and Ethics Committee of the Prince Charles Hospital,
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
YIJOM-3348; No of Pages 4
4
McNamara et al.
Brisbane, Queensland, Australia (HREC/ 10/QPCH/174). 6.
Patient consent
Not required.
7.
References
8.
1. Anderson T, Alpert B. Experience with rigid fixation of mandibular fractures and immediate function. J Oral Maxillofac Surg 1992;50:555–60. discussion 560–1. 2. Ellis E. Outcomes of patients with teeth in the line of mandibular angle fractures treated with stable internal fixation. J Oral Maxillofac Surg 2002;60:863–5. 3. Bradley RL. Treatment of fractured mandible. Am Surg 1965;31:289–90. 4. Rowe NL, Killey HC. Fractures of the facial : 181–2. 2nd ed. London: Livingstone; 1968 skeleton. 5. Marker P, Eckerdal A, Smith-Sivertsen C. Incompletely erupted third molars in the line of mandibular fractures. A retrospective
9.
10.
11.
analysis of 57 cases. Oral Surg Oral Med Oral Pathol 1994;78:426–31. Spiessl B. Closed fractures. In: Spiessl , editor. Internal fixation of the mandible. Berlin: Springer; 1989. p. 199. [chapter 5]. Thaller SR, Mabourakh S. Teeth located in the line of mandibular fracture. J Craniofac Surg 1994;5:16–9. Gerbino G, Tarello F, Fasolis M, De Gioanni PP. Rigid fixation with teeth in the line of mandibular fractures. Int J Oral Maxillofac Surg 1997;26:182–6. Rubin MM, Koll TJ, Sadoff RS. Morbidity associated with incompletely erupted third molars in the line of mandibular fractures. J Oral Maxillofac Surg 1990;48:1045–7. discussion 1048. Anastassov DT, Vuvakis VM. Mandibular fracture complications associated with the third molar lying in the fracture line. Folia Med (Plovdiv) 2000;42:41–6. Soriano E, Kankou V, Morand B, Sadek H, Raphae¨l B, Bettega G. Fractures of the mandibular angle: factors predictive of infectious
complications. Rev Stomatol Chir Maxillofac 2005;106:146–8. 12. Shetty V, Freymiller E. Teeth in the line of fracture: a review. J Oral Maxillofac Surg 1989;47:1303–6. 13. Bobrowski A, Sonego C, Chagas O. Postoperative infection associated with mandibular angle fracture treatment in the presence of teeth on the fracture line: a systematic review and meta-analysis. Int J Oral Maxillofac Surg 2013;42:1041–8. 14. Rai S, Pradhan R. Tooth in the line of fracture: its prognosis and its effects on healing. Indian J Dent Res 2011;22:495–6.
Address: Zeb McNamara Royal Brisbane and Women’s Hospital Herston Queensland Australia Tel: +61 0736468111 E-mail: [email protected]
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
Int. J. Oral Maxillofac. Surg. 2016; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2016.01.007, available online at http://www.sciencedirect.com
Randomized Controlled Trial Trauma
Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial
Z. McNamara1, G. Findlay1, P. O’Rourke2, M. Batstone1 1
Department of Oral and Maxillofacial Surgery, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia; 2 Statistics Unit, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
Z. McNamara, G. Findlay, P. O’Rourke, M. Batstone: Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial. Int. J. Oral Maxillofac. Surg. 2016; xxx: xxx–xxx. # 2016 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.
Abstract. The treatment dilemma provided by asymptomatic third molars in mandibular angle fractures remains controversial. This prospective randomized controlled trial was undertaken to determine whether there is an advantage to extraction or retention of the third molar whilst repairing a mandibular angle fracture. Sixty-four patients were allocated randomly to the two treatment groups. All underwent open reduction and internal fixation (ORIF) with standard postoperative care. The primary outcome measure was uncomplicated fracture healing. Secondary measures were surgical duration, malocclusion, wound healing, nerve injury, and return to theatre. All patients had uncomplicated fracture healing. The incidence of nerve injury was 16% for the retention group compared with 39% for the removal group (P = 0.038). The average operating time for ORIF and third molar retention cases was 58.5 min and for ORIF and third molar removal cases was 66.3 min (P = 0.26). There was no statistically significant difference between groups for wound healing, occlusion outcomes, or return to theatre. Given the additional risk of nerve injury and the additional operating time required for removal of a third molar, in the absence of an absolute indicator for removal of the third molar, it appears justifiable to advise retaining the tooth in the line of a mandibular angle fracture.
Accepted for publication 14 January 2016
The treatment of mandibular angle fractures has evolved over the years from closed reduction with a period of intermaxillary fixation, to open reduction with internal fixation (ORIF).1 One aspect of the ORIF procedure that remains
85% contained a third molar.2 Historically, extraction of the tooth in the fracture line was advocated, as this was thought to decrease the risk of infection and the need for removal of the wisdom tooth and plating at a later date.3,4 However, over
0901-5027/000001+04
controversial at present is the management of an asymptomatic wisdom tooth in the line of an angle fracture. This issue is important as this treatment dilemma is common. A study by Ellis showed that out of 402 angle fractures,
Key words: randomized controlled trial mandibular angle fractures; internal fixation; third molars.
# 2016 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons.
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
YIJOM-3348; No of Pages 4
2
McNamara et al.
the years this view has been challenged with the counter-argument that extraction of the third molar risks loss of bone, making reduction and plating more difficult, increases the surgical time, and increases the risk to the inferior dental nerve. At present there is conflicting information in the literature concerning the question of extracting or retaining an asymptomatic third molar in the line of a mandibular angle fracture, with no prospective randomized controlled trials conducted.2,5–12 Thus clinicians have to use their best judgement rather than evidencebased medicine in weighing the benefits and risks of removing a third molar in the line of an angle fracture against the benefits and risks of retaining it.2 The aim of this study was to compare the outcomes of fractures of the mandibular angle with random allocation to removal or retention of the third molar tooth. Methods Trial design
A prospective randomized controlled trial was performed. There were no changes to the methods after trial commencement. All patients presenting to the maxillofacial unit with a mandibular angle fracture requiring ORIF (Table 1) and who were 18 years of age or older were considered for inclusion in the study. Patients who could not give informed consent and patients with absolute indicators for the removal of third molars in angle fractures (Table 2) were excluded. Randomization was accomplished by sealed envelopes containing allocation to one of the two study groups. Sixty-four patients gave consent and were deemed eligible for the trial.
Table 1. Indicators for open reduction and fixation of a mandibular angle fracture. 1 Unfavourable fracture 2 Inability to obtain adequate occlusion by closed techniques 3 Infection (peri-apical/pericoronitis) 4 Fracture of tooth/roots
Table 2. Absolute indicators for removal of third molars.12 1 Caries 2 Mobile tooth 3 Infection (peri-apical/pericoronitis) 4 Fracture of tooth/roots 5 Pathology associated with third molar 6 Preventing adequate fracture reduction
Ethical approval for the study was granted by the necessary human research and ethics committee. Participants
Patients were assessed on presentation and standard imaging was obtained (panoramic radiographs and postero-anterior mandible X-rays). Demographic data including age, sex, smoking status, diabetes, and indigenous ethnicity were documented. Examination findings related to post-trauma alveolar nerve function were also recorded. Randomization then occurred by the participant drawing one of two possible envelopes, indicating which arm of the trial they would be included in. Participants were not blinded to their allotted treatment.
Results Participant flow
Sixty-four patients were enrolled in the study. The randomization process allocated 31 patients to the retention group and 33 patients to the removal group. All allotted patients underwent treatment as per their group. Patient demographics (Table 3)
There was no statistically significant difference between the groups regarding sex (P = 0.19), mean age at injury (P = 0.78), or the average number of fractures treated (P = 0.56). Furthermore, there was no statistically significant difference between the groups regarding smoking status (P = 0.86), diabetic comorbidity (P = 1.00), or indigenous ethnicity (P = 0.28).
Surgical details
Surgery was performed under general anaesthesia predominantly by a maxillofacial surgeon (GF). If not the primary operator, the surgeon (GF) was present as an assistant. All angle fractures were secured with a single 2.0-mm miniplate via a combined transoral incision and transbuccal trocar. The fractured segments were approximated visually with the dentition held in occlusion by the assistant whilst fixation was applied. Resorbable sutures were utilized for wound closure. Standard clinical and radiographic postoperative follow-up was undertaken. Outcomes
The primary outcome measure was uncomplicated fracture healing. The secondary measures were wound issues (wound breakdown/infections/collections), operative duration, malocclusion, inferior dental nerve (IDN) injury, and return to theatre. Surgeons undertook each postoperative patient assessment, but they were not blinded to which group patients had been allocated. Patients who did not attend clinic review appointments were deemed to have had nil negative outcomes. Categorical data were summarized as frequencies, and comparisons across allocated groups were done by cross-tabulations and x2 tests for significance. Continuous variables were summarized as the mean and range, and comparisons between groups were done using the independent samples t-test or the Mann–Whitney U-test. All significance tests used a two-sided P-value of 0.05.
Primary outcome
The primary outcome measure was uncomplicated fracture healing. Each group, removal and retention, had one return to theatre for non-union. Both return cases had an uneventful postoperative recovery following the second surgery. Therefore all 64 cases had eventual complete fracture healing.
Secondary outcome measures (Table 4)
The average surgical time for retention cases was 58.5 min and for removal cases was 66.3 min; however this difference between the groups was not statistically significant (P = 0.26). All patients underwent X-ray postoperatively. Furthermore, all patients had at least one postoperative review. The follow-up period for the removal and retention groups was similar: follow-up ranged from 1 to 164 days (mean 27 days, median 12 days) in the removal group and from 1 to 164 days (mean 26 days, median 27 days) in the retention group (P = 0.49, Mann–Whitney U-test). With regard to wound issues, the removal group (9.1%) had a higher rate than the retention group (0%), but this difference between the groups was not statistically significant (P = 0.09). The incidence of malocclusion was similar in the retention group (12.9%) and removal group (12.1%) (P = 0.92). Importantly the incidence of IDN injury showed a significant difference (P = 0.038), with the retention group (16.1%) showing a lower incidence than the removal group (39.4%).
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
YIJOM-3348; No of Pages 4
Third molar removal/retention in angle fractures Table 3. Demographics of patients included in the study and average number of fractures treated. Study group Retention (n = 31)
Removal (n = 33)
30 1
29 4
23 18–46 1.71
23 18–44 1.79
Sex Male Female Age, years Mean Range Average number of fractures treated
P-value 0.19 0.78 0.56
Table 4. Secondary outcome measures. Study group Retention (n = 31) Surgical time, min Mean Range Wound issues, % Malocclusion, % IDN injury, %
58.5 14–109 0% 12.9% 16.1%
Removal (n = 33) 66.3 19–122 9.1% 12.1% 39.4%
P-value 0.26 0.09 0.92 0.038
IDN, inferior dental nerve.
Return to theatre occurred twice during this study. Each group, removal and retention, had one occurrence. In the retention case, the patient had continuing postoperative pain and a subsequent follow-up Xray showed a non-union of the angle fracture. For the removal case, the patient had an ongoing wound infection at the surgical site and a persistent malocclusion. A follow-up X-ray also showed non-union of the angle fracture. Both return cases had an uneventful postoperative recovery following the second surgery. Discussion
Randomization provided two groups with a similar composition in terms of sex, ethnicity, age, and smoking status. It was expected that this randomization would also result in similar levels of preoperative paresthesia. The same surgeon (GF) was present during all operative procedures thus removing one cause of bias. Following the surgery, both groups had a similar follow-up regimen and observation time period. It is believed that this process enabled a meaningful study of comparison between the two groups. Ellis previously reported a 19.5% infection rate when the tooth was present in the angle fracture as compared to 19.0% when the tooth was extracted.2 The results of the present study differ from those of that previous study. In the retention group, none of the 31 patients (0%) had postoperative wound issues, while in the removal group, three of the 33 patients (9.1%) had such issues. Although this did not reach
statistical significance (P = 0.09), a trend towards greater wound complications with third molar removal was seen in the present study. Importantly, a recent systematic review and meta-analysis also showed that there was no significant statistical difference between removing or retaining the tooth in the line of fracture with regard to the occurrence of postoperative infection.13 However it is important to note that this analysis included only three prospective trials, none of which were randomized. A previous non-randomized prospective trial conducted by Rai and Pradhan in India commented on the discrepancy in occlusion between the groups.14 They reported that the removal group (16.7%) had a higher occlusion discrepancy compared to the retention group (13.3%).14 Although the result was not statistically significant, they hypothesized that the removal of the third molar causes a loss of contact and continuity in the fracture, and thus more chances of displacement or collapse during fixation.14 The results of the present study regarding malocclusion in the two groups, although not significant, differed from their study. The present study showed a minimal difference between the groups: retention group 12.9% and removal group 12.1%. So perhaps the loss of contact and continuity in the fracture is less of a problem than hypothesized. It is acknowledged that direct comparison of studies from different units and countries is difficult, as the aetiology of fractures, socio-economic status of the
3
patients, patient compliance, quality of post-surgical care, and definitions of complications may vary. Several weaknesses of this study should be acknowledged. Firstly, neither the patient nor the operating surgeon nor the assessor was blinded to the treatment allocation. For several reasons this is impossible, but most notably the postoperative X-ray reveals a tooth socket or the presence of a tooth depending on allocation. Secondly, like most studies on facial trauma, patient return for follow-up was poor, which limits the validity of results, particularly long-term factors such as nerve recovery. Thirdly, some of the values measured may have achieved statistical significance had the study recruited more patients. For example, wound issues showed a trend towards increased problems in the removal group. Finally the principal surgeon (GF) is very experienced and thus it may not be possible to extrapolate the results achieved to other units. Importantly this prospective trial looked at the risk to the IDN when considering retaining or removing the third molar in an angle fracture. A statistically significant difference was found between the groups (P = 0.038). Perhaps understandably, patients in the removal group reported a higher incidence of decreased sensation in the distribution of the IDN (39.4% vs. 16.1% in the retained group). During removal of the third molar, the displacement of the fracture fragments during the procedure and extra time taken to complete the procedure, with subsequent swelling, increase the patient risk when compared to the risk in the retained group patients. Given the additional risk of nerve injury and the additional operating time required for removal of a third molar, in the absence of an absolute indicator for removal of the third molar the authors would advise the retaining of an asymptomatic wisdom tooth in the line of a mandibular angle fracture. Funding
None. Competing interests
None. Ethical approval
Ethical approval for the study was granted by the Human Research and Ethics Committee of the Prince Charles Hospital,
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007
YIJOM-3348; No of Pages 4
4
McNamara et al.
Brisbane, Queensland, Australia (HREC/ 10/QPCH/174). 6.
Patient consent
Not required.
7.
References
8.
1. Anderson T, Alpert B. Experience with rigid fixation of mandibular fractures and immediate function. J Oral Maxillofac Surg 1992;50:555–60. discussion 560–1. 2. Ellis E. Outcomes of patients with teeth in the line of mandibular angle fractures treated with stable internal fixation. J Oral Maxillofac Surg 2002;60:863–5. 3. Bradley RL. Treatment of fractured mandible. Am Surg 1965;31:289–90. 4. Rowe NL, Killey HC. Fractures of the facial : 181–2. 2nd ed. London: Livingstone; 1968 skeleton. 5. Marker P, Eckerdal A, Smith-Sivertsen C. Incompletely erupted third molars in the line of mandibular fractures. A retrospective
9.
10.
11.
analysis of 57 cases. Oral Surg Oral Med Oral Pathol 1994;78:426–31. Spiessl B. Closed fractures. In: Spiessl , editor. Internal fixation of the mandible. Berlin: Springer; 1989. p. 199. [chapter 5]. Thaller SR, Mabourakh S. Teeth located in the line of mandibular fracture. J Craniofac Surg 1994;5:16–9. Gerbino G, Tarello F, Fasolis M, De Gioanni PP. Rigid fixation with teeth in the line of mandibular fractures. Int J Oral Maxillofac Surg 1997;26:182–6. Rubin MM, Koll TJ, Sadoff RS. Morbidity associated with incompletely erupted third molars in the line of mandibular fractures. J Oral Maxillofac Surg 1990;48:1045–7. discussion 1048. Anastassov DT, Vuvakis VM. Mandibular fracture complications associated with the third molar lying in the fracture line. Folia Med (Plovdiv) 2000;42:41–6. Soriano E, Kankou V, Morand B, Sadek H, Raphae¨l B, Bettega G. Fractures of the mandibular angle: factors predictive of infectious
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Address: Zeb McNamara Royal Brisbane and Women’s Hospital Herston Queensland Australia Tel: +61 0736468111 E-mail: [email protected]
Please cite this article in press as: McNamara Z, et al. Removal versus retention of asymptomatic third molars in mandibular angle fractures: a randomized controlled trial, Int J Oral Maxillofac Surg (2016), http://dx.doi.org/10.1016/j.ijom.2016.01.007