Late mandibular fracture occurring in the postoperative period after third molar removal: systematic review and analysis of 124 cases

Abstract

Factors associated with the diagnosis, aetiology, and treatment of mandibular fractures occurring during the postoperative period following the removal of a lower third molar are discussed. The following databases were searched using specific key words: PubMed/MEDLINE, LILACS, Embase, and Scopus. The search yielded 124 cases. Sex, age, side, tooth position and angulation, bone impaction, relationship between the tooth and the inferior alveolar nerve, local pathological conditions, aetiology of the fracture, symptomatology, and time between surgery and fracture, as well as any displacement of the fracture and the treatment of the fracture, were evaluated. Data were tabulated and the χ 2 statistical test was applied ( P < 0.05). Male patients aged >35 years, with teeth in positions II/III and B/C, complete bony impaction, and local bone-like alterations, were found to have a higher frequency of fracture and pericoronitis ( P < 0.05). Late fractures generally occurred between the second and fourth postoperative weeks ( P < 0.05). They were generally not displaced and the typical treatment was the non-surgical approach ( P < 0.05). It is concluded that the risk of mandibular fracture after extraction is associated with excessive ostectomy and/or local alterations. At-risk patients should be thoroughly briefed on the importance of a proper postoperative diet.

The surgical removal of a lower third molar is a common procedure in the dental clinic. Potential complications include infection, bleeding, haemorrhage, lesion of the inferior alveolar nerve, trismus, and mandibular angle fractures. A mandibular angle fracture is the most serious complication occurring during surgery; however, this is very rare, with an incidence of 0.0034 to 0.0075%. The incidence of late mandibular angle fracture occurring in the postoperative period after the surgical removal of a lower third molar is less than 0.005%.

Factors contributing to the risk of mandibular angle fracture after the extraction of a third molar include the level of impaction on the bone around the tooth, the dental anatomy and the dental root characteristics, the side of the fracture, previous local infections, age, sex, amount of time postoperative, bruxism, and whether the patient is an active athlete.

The choice of treatment depends on the fracture characteristics and the surgeon’s preference, and includes more conservative approaches such as a soft diet, maxillomandibular fixation, and surgical treatment by means of reduction and fixation of the fracture.

The aim of this systematic review was to report and discuss the factors associated with the aetiology and treatment of mandibular fractures in the postoperative period following lower third molar removal.

Methods

The PRISMA statement was followed for the systematic review, as well as models proposed in the literature. The articles were selected individually by two of the authors (WRP and JPB) and there was no disagreement in the selection of the articles.

Eligibility criteria

The studies selected for this systematic review met the criteria established by the PICO framework: (1) population: patients presenting for the extraction of a lower third molar; (2) intervention: patients undergoing lower third molar extraction; (3) comparison: patients presenting with mandibular angle fractures after lower third molar extraction; (4) outcome: the main outcome of the study was the relationship between lower third molar removal and the incidence of mandibular angle fracture.

Literature search strategy

An electronic search without date or language restriction was performed in January 2016 in the following electronic databases: PubMed/MEDLINE, LILACS, Embase, and Scopus.

The key words “Molar, Third” and “Mandibular Fractures” were selected, which are available in the medical subject headings (MeSH, PubMed). These search terms were then used in the following combinations: (“Molar, Third”[Mesh]) AND (“Mandibular Fractures”[Mesh]), (“Dental Extraction”) AND (“Mandibular Fractures”), and (“Tooth Extraction”) AND (“Mandibular Fractures”) for the PubMed database; “Dental Extraction” AND “Mandibular Fractures”, “Tooth Extraction” AND “Mandibular Fractures”, and “Molar, Third” AND “Mandibular Fractures” for the Scopus database; “Dental Extraction” AND “Mandibular Fractures”, “Tooth Extraction” AND “Mandibular Fractures”, and “Molar, Third” AND “Mandibular Fractures” for the Embase database; (Dental Extraction) AND (Mandibular Fractures), (Tooth Extraction) AND (Mandibular Fractures), (Molar, Third) AND (Mandibular Fractures), (Exodontia) AND (Fratura mandibular), (Extração dental) AND (Fratura mandibular), (Extracción dental) AND (fractura mandibular), and (Exodoncia) AND (fractura mandibular) for the LILACS database.

Study selection

Inclusion criteria encompassed the following: systematic reviews that included new cases, randomized studies, prospective studies, retrospective studies, clinical cases, case series, letters to editor, and expert opinions on late fractures after lower third molar extraction, with no restrictions on age or sex.

Articles that reported fractures without specification of the time of occurrence (preoperative or postoperative period) and those that did not report any of the data required for this review were excluded.

The selection of studies was conducted independently by two calibrated examiners (WRP and JPB). The inter-examiner (kappa) test was used to evaluate the selection of titles and abstracts and full-texts for reading and interpretation, resulting in concordance test values of κ = 1, 1 for PubMed/MEDLINE, κ = 1, 1 for LILACS, κ = 1, 1 for Embase and κ = 1, 1 for Scopus. Finally, a total of 36 articles were considered eligible for this review.

Data items

The following data, when available, were extracted from the studies included in the final analysis: year, number of cases, sex, age, side of the extracted tooth (fracture side), tooth position (Pell and Gregory classification ), tooth angulation (Winter classification), degree of impaction (partial or complete bony impaction), relationship of the tooth to the mandibular canal (adjacent or superimposed), local pathological conditions, fracture aetiology, symptomatology, time between surgery and the fracture, and fracture displacement and treatment.

Risk of bias in individual studies

The selected manuscripts were analyzed according to the clinical evidence. The manuscripts were separated into the following categories: systematic review/case series, case series, case report, retrospective study, letter to the editor, and expert opinion on a case series. The systematic review/cases series, case series, cases report, and retrospective studies were sorted according to their level of evidence, as proposed by the National Health and Medical Research Council of Australia (NHMRC).

With regard to summary measures, the relationships between the frequency of fractures and the following parameters were analyzed: the kind of inclusion, the aetiology of the fracture, the side of the fracture, age, and the time between surgery and the fracture.

Risk of bias across studies

A few studies reported mandibular fractures occurring through an external trauma during the postoperative period following third molar extraction. Thus, it was not possible to claim that these fractures occurred entirely due to the tooth extraction, since the external trauma would be an aetiological factor.

Statistical analysis

Data were tabulated in Microsoft Excel 2013 and analyzed by descriptive statistics (distribution frequency). Associations between the occurrence of fracture and other sample factors, such as age, sex, and third molar position, were analyzed by χ 2 test, considering a significance level of 5% ( P < 0.05). These tests were run using the statistical software SigmaPlot 12.3 (Systat Software Inc., San Jose, CA, USA).

Results

The database search returned 476 articles after the removal of duplicates. Following the screening of titles and abstracts, 423 records were excluded. Fifty-three full-text articles were assessed for eligibility ( Fig. 1 ). Finally, 36 articles were selected; these articles included 124 clinical cases associated with mandibular fracture after the removal of a lower third molar ( Table 1 ).

Fig. 1
Flow diagram of the study selection for the systematic review.

Table 1
Reports of mandibular fracture after the removal of a lower third molar.
Authors Year Number of cases Article type Level of evidence a
Belvèze 1954 1 Case report IV Poor
Nyul 1959 1 Case report IV Poor
Lautenbach 1966 1 Case report IV Poor
Haunfelder and Tetsch 1972 2 Case series IV Poor
Berlin 1977 1 Case series IV Poor
Borea et al. 1977 2 Case report IV Poor
Einrauch et al. 1980 4 Case series IV Poor
Schneider 1980 1 Case report IV Poor
Roth 1981 1 Case report IV Poor
Cantaloube et al. 1982 1 Case report IV Poor
de Silva 1984 1 Case report IV Poor
Litwan and Götzfried 1987 4 Case series IV Poor
Härtel et al. 1988 2 Case series IV Poor
Dunstan and Sugar 1997 2 Case series IV Poor
Iizuka et al. 1997 12 Retrospective study III-3 Satisfactory
Becktor and Schou 1998 1 Case report IV Poor
Perry and Goldberg 2000 28 Expert opinion IV Poor
Krimmel and Reinert 2000 6 Retrospective study III-3 Satisfactory
Libersa et al. 2002 10 Retrospective study III-3 Satisfactory
Tamashiro-Higa and Inclán 2003 1 Case series IV Satisfactory
Arrigoni et al. 2004 7 Retrospective study III-3 Satisfactory
Wagner et al. 2005 14 Retrospective study III-3 Satisfactory
Werkmeister et al. 2005 1 Retrospective study III-3 Satisfactory
Komerik and Karaduman 2006 1 Case report IV Poor
Wagner et al. 2007 1 Case report IV Poor
Khan et al. 2009 1 Letter to the editor IV Poor
Chrcanovic and Custódio 2010 1 Case report IV Poor
Kao et al. 2010 1 Case report IV Poor
Grau-Manclús et al. 2011 4 Retrospective study III-3 Satisfactory
Tieghi et al. 2011 1 Case report IV Poor
Ishii et al. 2012 1 Case report IV Poor
Ethunandan et al. 2012 3 Systematic review/case series I Satisfactory
Duarte et al. 2012 1 Case series IV Poor
Cutilli et al. 2013 3 Case series IV Poor
Andrade et al. 2013 1 Case report IV Poor
Corrêa et al. 2014 1 Letter to the editor IV Poor
Total 124

a Level of evidence according to the National Health and Medical Research Council.

Sex and age

The patient’s sex was documented for 80 of the 124 cases and the exact age for 102 of them. Fifty-nine cases involved male patients (73.7%) and 21 involved female patients (26.2%) ( P < 0.001). Patients between the ages of 46 and 60 years were the most affected, comprising 34.3% of the 102 cases ( P < 0.05) ( Table 2 ).

Table 2
Sex and age of patients with late fracture after removal of a lower third molar.
Variable Number of cases %
Sex
Male 59 73.7
Female 21 26.2
Age (years)
<25 10 9.8
26–35 22 21.6
36–45 26 25.5
46–60 35 34.3
>60 9 8.8

Local factors associated with the risk of fracture

The side of the mandibular fracture was documented in 67 cases. The left side was affected in 35 cases (52.2%) and the right side in 30 cases (44.8%) ( P = 0.16) ( Table 3 ).

Table 3
Local factors that could be associated with the risk of mandibular fracture.
Variable Number of cases %
Side
Left 35 52.2
Right 30 44.8
Bilateral 2 3.0
Localization (Pell and Gregory)
Anteroposterior
I 4 10.2
II 24 61.5
III 11 28.2
Vertical
A 2 5.1
B 16 41.0
C 21 53.8
Angulation
Distoangular 9 12
Horizontal 14 18.7
Mesioangular 27 36
Vertical 25 33.3
Degree of impaction
Complete 35 64.8
Partial 19 35.2
Relationship to IAN
Adjacent 19 50
Superimposed 19 50
History of infection
None 11 26.8
Pericoronitis 28 68.3
Periodontal pocket 2 4.9
Pathological association
None 28 53.8
Expanded dental follicle 9 17.3
Follicular cyst 10 19.2
Stafne defect 3 5.8
Odontogenic tumour 1 1.9
Reabsorption 1 1.9
IAN, inferior alveolar nerve.

The tooth position was recorded using the Pell and Gregory classification system in 39 cases. Classes II and III, and classes B and C accounted for higher proportions of cases than class I and class A ( P < 0.05) ( Table 3 ).

The tooth angulation was reported in 75 cases. The most frequent angulation was mesioangular, with 27 cases (36%), followed by vertical (33.3%), horizontal (18.7%), and distoangular (12.0%) ( Table 3 ). There was no statistical difference between the mesioangular and vertical categories ( P > 0.05).

The degree of bony impaction was reported in 54 cases; 35 (64.8%) were completely impacted and 19 (35.2%) were partially impacted ( Table 3 ) ( P < 0.05).

The proximity of the tooth to the inferior alveolar nerve was reported in 38 cases. The tooth was superimposed on the nerve in 19 cases (50%) and was adjacent to the nerve in 19 cases (50%) ( Table 3 ) ( P > 0.05).

The history of infection was reported in 41 cases. Pericoronitis was the most frequent infection, with 28 cases (68.3%) ( Table 3 ) ( P < 0.05).

The presence (or absence) of an associated pathological process was reported in 52 cases. In 28 cases (53.8%) there was no pathological process associated with the tooth, and in 24 cases (46.2%) there was an associated pathology ( P > 0.05). There were 10 cases of a follicular cyst (19.2%), and an expanded dental follicle was present in nine cases (17.3%) ( Table 3 ) ( P > 0.05).

Factors related to the diagnosis, characteristics, and treatment of the fracture

The aetiology of the fracture was reported in 46 cases, and the most common was mastication (35 cases, 76.1%) ( P < 0.05) ( Table 4 ). External traumas were reported in four cases. Amongst these, two fractures were due to sports traumas, one to a fall, and one to a car crash trauma. It was not possible to ascertain whether the mandibular fracture occurred as a result of the tooth extraction. Nevertheless, its frequency was not statistically significant ( P > 0.05).

Table 4
Factors related to the diagnosis, characteristics, and treatment of the fracture.
Variable Number of cases %
Aetiology
Mastication 35 76.1
Yawn 3 6.5
Sport 2 4.3
Exercise 1 2.2
Fall 1 2.2
Car accident 1 2.2
Osteomyelitis 3 6.5
Symptomatology
Crackling 45 50.6
Pain 26 29.2
Oedema 11 12.3
Occlusal alteration 2 2.2
Trismus 3 3.4
Unnoticed 1 1.1
Bleeding 1 1.1
Time (weeks)
1 7 11.5
2 20 32.8
3 17 27.9
4 11 18.0
5 2 3.3
≥6 4 6.5
Displacement
None 39 79.6
Minor 4 8.2
Yes 6 12.2
Treatment
Soft diet 17 17.7
MMF 43 44.8
ORIF 27 28.1
ORIF + MMF 5 5.2
ORIF + mandibular reconstruction 2 2.1
None 2 2.1
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Dec 14, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Late mandibular fracture occurring in the postoperative period after third molar removal: systematic review and analysis of 124 cases
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