Ectopic third mandibular molar: evaluation of surgical practices and meta-analysis

Abstract

Objectives
To identify the preferred surgical approach (intra- or extra-oral) to remove an ectopic third mandibular molar (ETMM) according on its location and presence of an associated cyst or cutaneous fistula, and to determine the indications for a graft or osteosynthesis.Materials and methodsA surgical practice questionnaire was distributed to oral and maxillo-facial surgeons attending a National Congress of the French Society of Stomatology, Maxillo-facial and Oral Surgery. A systematic review of the literature and meta-analysis was carried on Pubmed, Cochrane, Embase and ScienceDirect databases using the MeSH terms: “Ectopic teeth”, “Third molar”, “Mandibular”. One hundred and forty-three surgeons answered the questionnaire and the meta-analysis included 66 articles.ResultsFrom the questionnaire, the preferred surgical approach was intra-oral except when the ETMM was in the condyle, when it was extra-oral (69.5%; p < 0.001). In the meta-analysis, an extra-oral approach was only indicated when a cutaneous fistula was present (90% vs. 35.9%; p = 0.002), irrespective of ETMM location. In the questionnaire and meta-analysis, the presence of a cyst did not change the approach (p < 0.05). The indications for a graft or osteosynthesis were a condylar location (p < 0.001), while a cutaneous fistula decreased the indication (p = 0.04) and a cyst (p = 0.009) was only associated with a graft.Conclusions
The preferential approach was intra-oral, except when the ETMM was condylar or a cutaneous fistula was present when an extra-oral approach was preferred. Osteosynthesis or a graft were more likely when the ETMM was in the condyle.Clinical relevanceThis study will help to orientate surgeons vis-à-vis ETMM treatment.

Full text

Vol.:(0123456789)
1 3
https://doi.org/10.1007/s00784-021-04018-z
REVIEW
Ectopic third mandibular molar: evaluation ofsurgical practices
andmeta‑analysis
JuliaCaillet1,2,3· BrunoPereira4· RomainCourtot1,2,3· IsabelleBarthélémy1,2,5· LaurentDevoize1,2,3,5·
ArnaudDepeyre1,6
Received: 13 April 2021 / Accepted: 31 May 2021
© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021
Abstract
Objectives To identify the preferred surgical approach (intra- or extra-oral) to remove an ectopic third mandibular molar
(ETMM) according on its location and presence of an associated cyst or cutaneous fistula, and to determine the indications
for a graft or osteosynthesis.
Materials and methods A surgical practice questionnaire was distributed to oral and maxillo-facial surgeons attending a
National Congress of the French Society of Stomatology, Maxillo-facial and Oral Surgery. A systematic review of the lit-
erature and meta-analysis was carried on Pubmed, Cochrane, Embase and ScienceDirect databases using the MeSH terms:
“Ectopic teeth”, “Third molar”, “Mandibular”. One hundred and forty-three surgeons answered the questionnaire and the
meta-analysis included 66 articles.
Results From the questionnaire, the preferred surgical approach was intra-oral except when the ETMM was in the condyle,
when it was extra-oral (69.5%; p < 0.001). In the meta-analysis, an extra-oral approach was only indicated when a cutane-
ous fistula was present (90% vs. 35.9%; p = 0.002), irrespective of ETMM location. In the questionnaire and meta-analysis,
the presence of a cyst did not change the approach (p < 0.05). The indications for a graft or osteosynthesis were a condylar
location (p < 0.001), while a cutaneous fistula decreased the indication (p = 0.04) and a cyst (p = 0.009) was only associated
with a graft.
Conclusions The preferential approach was intra-oral, except when the ETMM was condylar or a cutaneous fistula was
present when an extra-oral approach was preferred. Osteosynthesis or a graft were more likely when the ETMM was in the
condyle.
Clinical relevance This study will help to orientate surgeons vis-à-vis ETMM treatment.
Keywords Ectopic tooth· Third molar· Mandibular surgery approach· Bone graft· Osteosynthesis
Introduction
A tooth is ectopic if it is not following its normal course of
growth and is outside the alveolar arch. Third mandibular
molars may have several ectopic locations: corpus, angle,
ramus, coronoid process, mandibular notch or condyle unit.
A tooth is impacted if it does not connect with the oral
cavity and remains contained inside the anatomic structures,
namely the maxillary bones or mandible. An impacted tooth
can also be ectopic. Impacted third mandibular molars are
found in 20–30% of the population, with a higher prevalence
in females [1–6], while an ectopic third mandibular molar
(ETMM) is relatively rare and only a few cases have been
reported in the literature. ETMMs affect around 1% of the
general population [7]. Several theories explain the origin of
* Arnaud Depeyre
depeyrearnaud@gmail.fr
1 Oral andMaxillofacial Department, Estaing Hospital,
CHU Clermont Ferrand, 1 Place Lucie Aubrac,
63003ClermontFerrandCedex1, France
2 Faculty ofMedicine, Université D’Auvergne,
63001ClermontFerrandcedex1, France
3 Odontology Department, Estaing Hospital, CHU Clermont
Ferrand, 63003ClermontFerrand, France
4 Biostatistics Unit, Department ofClinical
Research andInnovation, CHU Clermont Ferrand,
63000ClermontFerrand, France
5 Inserm U1107 Neuro-Dol, Trigeminal Pain andMigraine,
Faculty ofDental Surgery, 63100Clermont-Ferrand, France
6 Hôpital Privé de La Loire, Ramsay Générale de Santé, 39
boulevard de la Palle, 42100SaintEtienne, France
/ Published online: 17 June 2021
Clinical Oral Investigations (2021) 25:4781–4799
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