Literature Review/Oral Surgery

 

Prophylactic removal of unerupted asymptomatic third molars: is it justifiable?

 

Marlus da Silva Pedrosa^I; Evelyn Bianca Soares Silva^I; Thais Oliveira Cordeiro^I; Luiz Gustavo Fernandes Lima Oliveira^II; Rodrigo Richard da Silveira^III; Cláudio Heliomar Vicente da Silva^IV; José Guilherme Férrer Pompeu^V

 

^I Department of Dentistry, DeVry Facid – DeVry Education Group, Terezina, PI, Brazil
^II Private Practice, Luiz Gustavo Aesthetic Dentistry and Oral Implantology, Terezina, PI, Brazil
^III Department of Restorative Dentistry, Federal University of Minas Gerais – UFMG, Belo Horizonte, MG, Brazil
^IV Department of Prosthetic Dentistry and Maxillofacial Surgery, Federal University of Pernambuco – UFPE, Recife, PE, Brazil
^V Department of Restorative Dentistry, Federal University of Piauí – UFPI, Terezina, PI, Brazil

 

Endereço para correspondência

 

 

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ABSTRACT

Objective: to review the literature currently available on the evidence that does or does not justify the prophylactic extraction of unerupted asymptomatic third molars. Material and Methods: the electronic databases PubMed, Capes Periodicals, Web of Science and Scopus were searched from November to December 2016 by two authors, simultaneously, using as search terms: Terceiro Molar/Molar, Third AND Extração Profilática/Prophylatic Removal OR Prophylatic Extraction. We included articles from original research and clinical trials published in English and Portuguese. No limits were applied to the date of publication. Review articles and clinical case reports were removed. Results: we identified 13 studies that addressed, at some aspect, the prophylactic removal of unerupted asymptomatic third molars. The results of this literature review which alluded to the potential for the formation of pathological alterations in asymptomatic third molars are conflicting; While some justifies the prophylactic procedure based on the possible formation of associated lesions, other scientific evidence does not support such practice. Conclusion: in view of the conflicting viewpoints found in the literature, the prophylactic removal of asymptomatic third molars requires case-by-case evaluation of each patient, and the decision-making process, regarding the retention versus the prophylactic removal of these teeth should be based on scientific evidence combined with the clinical experience of the professional.

Keywords: Oral surgery; Third molar; Unerupted tooth; Disease prevention.

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Introduction

The extraction of third molars is one of the most common procedures in the clinical practice of dentists worldwide. It is estimated that, in the United States, approximately 10 million impacted teeth are extracted annually from approximately 5 million individuals, generating a revenue of 3 billion dollars.^1,2 In England and Wales, extractions of third molars between 1995 and 1996 totaled approximately 5.2 million pounds.³

Prophylactic extraction, the most common reason for extraction of third molars,⁴ is widely recognized by a considerable number of dental surgeons.^2,5 This fact is based on the association of these teeth with oral pathological changes such as pericoronitis, periodontal problems, caries in third or second molars, different types of odontogenic cysts and tumors as well as crowding of the lower incisors.^6-14

The scientific literature also mentions other reasons to justify this procedure, considering the fact that these teeth do not always play a functional role in the oral cavity as well as an increased risk for postoperative complications, pain and discomfort when their surgical removal is performed in more advanced aged patients.^15-21 However, other studies suggest that the lower third molars should not be removed prophylactically in some cases^2,14,22-23 and vigilant monitoring of these teeth is more appropriate strategy.²⁴

Debate about indications for prophylactic removal of impacted third molars remains heated.¹¹ The decision-making process regarding retention versus prophylactic removal of these teeth should be based on the available scientific evidence.²⁵ However, the literature is lacking in studies to support adequate clinical decision-making regarding prophylactic extraction of third molars.¹⁴ This study aimed to review the literature currently available on scientific evidence that does or does not justify the prophylactic extraction of unerupted asymptomatic third molars.

 

Material and Methods

For the purpose of this study, we followed guidelines provided by Moher et al.²⁶ in Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement.

Identification and Selection of Relevant Research

An exploratory bibliographic search was conducted from January to February of 2017 using the electronic databases: Public Medline (PubMed), Periódicos da Capes, Web of Science and Scopus. Two authors performed the search employing the term Third Molar in combination with Prophylactic removal OR Prophylactic Extraction (Table 1). Inclusion criteria were: original research articles and clinical trials published in Portuguese and English. No limits were applied to the year of publication.

 

 

 

Studies were identified and duplicates were removed. Subsequently, titles and abstracts were screened for relevance, considering the exclusion criteria. Next, the remaining studies were obtained in full-text and were screened using the self-same criteria, the eligible the ones being included in this review. We removed review studies, clinical case reports, articles not available in fulltext, and publications that did not address the prophylactic removal of unerupted asymptomatic third molars. Eligible studies also had their reference lists screened following the specified criteria for the eligible ones.

Data Collection and Analyses

All the selected articles addressed the relationship between third molars and pathological changes and included the following parameters: authorship, year of publication, country of publication, type of study, sample size (and age), outcomes measured, relevant data and results, and study considerations.

Based on the findings of the studies, we determined the following themes for critical analysis of the results: characteristics of the studies, prophylactic removal of third molars and implications for practice. Yet, considering our study design and its findings, we presented the section "study limitations".

 

Results

For this systematic review, the initial electronic search yielded a total of 540 titles found in the databases: PubMed, Periódicos da Capes, Web of Science and Scopus. 433 studies were excluded for duplication and the remaining 107 unique papers were screened for relevance to this study. 55 publications were excluded after reading their titles and abstracts. Then, the 52 remaining documents were obtained in full-text and assessed for eligibility in consideration of the prophylactic removal of unerupted asymptomatic third molars. After reading the documents in full text, 13 studies were included (Figure 1 and Table 2). No studies from reference lists were added due to their either not being eligible or not having come up on the database search.

 

 

 

 

 

Characteristics of the Studies

We identified 13 studies that addressed, in some respect, the prophylactic removal of asymptomatic third molars. The 13 documents fell into several different categories: retrospective (n = 5), prospective (n = 4), histopathological (n = 2), cross-sectional (n = 1), and histologic and immunohistochemical (n = 2).

According to our findings, we identified only six studies published at sporadic intervals within a ten-year time frame: 2001 (n = 1), 2005 (n = 1), 2006 (n = 1), 2008 (n = 2), e 2009 (n = 1). In the last six years, seven studies were published: 2011 (n = 2), 2013 (n = 2), 2015 (n = 1) and 2016 (n = 2) The results indicated the need for future research on the prophylactic extraction of unerupted asymptomatic third molars.

Prophylactic Removal of Unerupted Asymptomatic Third Molars

Table 2 presents the main findings of all the 13 selected articles that addressed the prophylactic removal of unerupted asymptomatic third molars and included the following parameters: authorship, year of publication, country of publication, type of study, sample size (and age), outcomes measured, relevant data and results, and study considerations.

Implications for Practice

In recent years, the shift in emphasis to nonintervention in patients with asymptomatic impacted third molars has been accompanied by a considerable debate.³⁷ The supporters of prophylactic removal argue that the benefits outweigh the risks. Nonetheless, the scientific evidence is too inconclusive to support prophylactic removal. Unfortunately, most of the clinical research has failed, leading to contradictory interpretations that have not completely clarified the relative risks and benefits of early intervention.³⁸

Conflicting reports persists surrounding to the incidence of pathological conditions associated with impacted third molars, and the subsequent need for prophylactic removal. The data remain limited regarding the long-term effects of unerupted third molars on adjacent teeth.³² According to Hicks,³⁸ unreliable data would serve only to fuel this debate and the controversy over proper protocols.

It is likely that disagreements persists on which clinical recommendations should be followed when considering the prophylactic removal of asymptomatic third molars.³⁹ Therefore, the decision to perform prophylactic removal of these teeth should be based on the probability of retained third molars causing future problems.³⁰

Thus, the prophylactic removal of asymptomatic third molars requires individual care and case-by-case evaluation of each patient and the decision-making process regarding the retention versus prophylactic removal of these teeth should be based on the available scientific evidence combined with the professional's clinical experience.

Study Limitations

This literature review has some limitations given that the literature is lacking in randomized clinical trials regarding of the prophylactic removal of unerupted asymptomatic third molars. Other limitation found by the authors was the lacking in some full texts publications. However, available scientific evidence were included in order to better work on the subject. Sample sizes found in most studies were acceptable.

 

Discussion

Prophylactic removal of unerupted asymptomatic third molars is defined as a surgical procedure in which the patient does not present or has not presented any symptoms or pathologies associated with unerupted third molars.²⁹ Currently, there is no general agreement as far as the necessity of surgical removal of asymptomatic third molars is concerned.

In order to minimize the risk of disease associated with these teeth³⁰ or to avoid complications at more advanced ages, due to the risk of trauma or mandibular fractures,^11,40 development of cysts and tumors,³⁶ patient's recovery and prognosis,⁴¹ some authors believe that all unerupted third molars should be removed. Nevertheless, in this sense, there is still a need to compare the morbidity rates of tooth removal in people of several age groups.³⁷

Occasionally, orthodontists propose the removal of asymptomatic third molars to complete orthodontic therapy.³⁰Despite the fact that the role of third molars has been the subject of research, clinical interest, and debate for years, there is still a lack of scientific evidence from high-quality clinical studies on this subject.⁴² However, Normando et al.⁴³ suggest that, in general, the best clinical conduct is not to proceed with the prophylactic extraction of third molars, except in situations where removal of a third molar is mandatory from the beginning of treatment.

The studies addressed in this literature review alluded to the potential for development of pathological alterations in unerupted asymptomatic third molars.^11-13,27-36 Some evidence shows a greater risk in the occurrence of mandibular fractures¹¹or associated lesions such as cysts,^11,12 especially dentigerous ones,^31,36 suggesting the prophylactic extraction of unerupted third asymptomatic molars might be a treatment option worth considering.

Other studies do not support such clinical conduct,¹⁷ considering that, even with the risk of occurrence of lesions¹³, which was relatively low,³⁰ the relationship between pathological changes and dental position was not statistically significant, and that it was not possible to come up with a significant cost-benefit relationship.²⁸

According to some authors,^28,32 caries in the distal region of the second molar seem to be a factor that justifies the extraction of asymptomatic third molars, especially if the tooth is mesiongulated. ³² However, given that distal caries in the second molars is not very common in cases of third molar impactions, the prophylactic removal of these impacted teeth may not be considered appropriate.³⁵

In this sense, in the absence of any other indication, the presence of radiologically diagnosable retention is not sufficient indication for the prophylactic removal of an asymptomatic third molar.²⁷ This is specially true given the lack of evidence from randomized clinical trials that this procedure would avoid painful or infectious pathological complications due to its retention.²⁵

 

Conclusion

There is some disagreement regarding the prophylactic extraction of unerupted asymptomatic third molars. Some authors justify the prophylactic removal based on the potential of development of pathological changes while other available scientific evidence does not support such conduct.

The routine removal of unerupted asymptomatic or disease- free third molars will require individual care and assessment. A case-by-case management protocol is needed. The close monitoring of these teeth may be an acceptable option.

The decision-making process regarding the retention versus prophylactic removal of unerupted asymptomatic third molars should be based on the available scientific evidences combined with the professional's clinical experience.

 

Acknowledgment

We thank Kevan Self from the Center for English as a Second Language at Southern Illinois University Carbondale for editing and proofreading this paper.

 

References

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Endereço para correspondência:
Marlus da Silva Pedrosa
e-mail: marluspedrosa@gmail.com

 

 

Recebido: 01/26/2017
Aceito: 03/06/2017