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Mesioangular impaction is associated with increased periodontal pocketing on the distal surface of the second molar
ARTICLE
HARM & ETIOLOGY
Mesioangular impaction is associated with increased periodontal pocketing on the distal surface of the second molar
ANALYSIS & EVALUATION
Kan, KW, Liu JKS, Lo ECM, Corbet EF, Leung WK. Residual periodontal defects distal to the mandibular second molar 6-36 months after impacted third molar extraction. J Clin Periodontol 2002;29:1004-11.
3
To determine the etiologic factors of periodontal pocketing distal to second molars after wisdom tooth extraction
Information not available
Cohort study
Original Article
Level of Evidence
Purpose
Source of Funding
Type of Study/Design
Summary SUBJECTS A total of 158 subjects of Chinese ethnicity were selected for this study. Mean age was 27 (SD, 7 years). Sixty-one subjects were men (39%) and 97 were women (61%). All of the patients had undergone surgical extraction of mandibular third molars at the Prince Philip Dental Hospital in Hong Kong in a period starting 36 months before the beginning of the study in July 1997.
EXPOSURE Mesioangular impaction, ie, impacted lower third molars when the long axes of the third and second molars diverge ≥30°.
MAIN OUTCOME MEASURE Residual periodontal defect on distal surface of second molar.
MAIN RESULTS A mesioangular impacted third molar, when compared with an upright impacted third molar, is associated with, on average, a 1-mm increased pocket depth (P = .001) on the adjacent second molar after extraction. J Evid Base Dent Pract 2003;3:149-50 © 2003 Mosby, Inc. All rights reserved. doi:10.1067/med.2003:57
149
Commentary CONCLUSIONS The presence of isolated deep periodontal pockets distal to second molars is relatively common in a periodontal practice. Third molars are often suspected as the potential etiologic factor for these isolated defects. The present study investigated the association between the radiographic appearance of third molars prior to extraction and the residual probing depths distal to second molars after extraction. The findings indicated that the angular position of the third molar at the time of extraction influenced the periodontal pocket depth distal to the adjacent second molar—a mesioangular impacted third molar was, on average, associated with a 1-mm increase in periodontal pocket depth, as compared with an upright or distally impacted third molar. The findings further suggested that if a mesioangular impacted third molar had a crestal radiolucency, the pocket depth distal of the second molar was, on average, 2.7 mm greater than the pocket depth of a third molar that was upright and that had no crestal radiolucency. ANALYSIS The major strength of this study was the systematic sampling of subjects from a total sample size of 3211 subjects. This approach minimized potential selection biases. A limitation of the current study is that those subjects whose second and third molars were extracted at the same time were deleted from the study. Since extraction of second molars is the worst possible outcome associated with with third molar removal, it is important to incorporate such outcomes in analyses. As the authors indicate, this study could not determine whether the defect was a consequence of the extration itself (socket in the distal area of the second molar) or of the surgical technique used for the extraction (ostectomy). Determining the impact of the surgical removal of third molars on second molars’ periodontal health was beyond the scope of this study. In future studies, consideration should be given to using a nonextraction
150 Kan et al
control group, obtaining periodontal probing measures prior to extraction, and providing a detailed description of the surgical technique used. However, addressing these issues may be challenging. The random assignment of individuals with symptomatic third molars to a nonextraction group may be difficult from an ethical perspective. The authors indicated that in their study a nonsurgical control group was not possible because the Oral and Maxillofacial Surgery Clinic of the Prince Philip Dental Hospital follows a strict protocol for impacted third molar removal whereby only those teeth that are found to cause problems in a patient are removed. In addition, obtaining preoperative probing measures on second molars is sometimes difficult, if not impossible, because of the close proximity of the third molar. Finally, as has been documented in medical surgical procedures,1 dental surgical techniques and expertise can also have a potentially significant effect on outcomes, leading to problems with generalizing the findings. Third molar impactions are common conditions, and their surgical removal is common. Their high prevalence suggests that it is important that future studies evaluate the prognosis for second molars with isolated distal periodontal pockets and, if the prognosis for these teeth turns out to be poor, the type of treatments that may help in improving the prognosis. The current study provided additional evidence on the type of third molar impactions likely to be associated with residual periodontal defects and will help in the design of these future studies. REFERENCE 1. Kantonen I, Lepantalo M, Salenius JP, Matzke S, Luther M, Ylonen K. Influence of surgical experience on the results of carotid surgery. The Finnvasc Study Group. Eur J Vasc Endovasc Surg 1998;15:155-60.
Reviewer: Simone Verardi, DDS University of Washington Seattle
Journal of Evidence-Based Dental Practice September 2003
HARM & ETIOLOGY
Mesioangular impaction is associated with increased periodontal pocketing on the distal surface of the second molar
ANALYSIS & EVALUATION
Kan, KW, Liu JKS, Lo ECM, Corbet EF, Leung WK. Residual periodontal defects distal to the mandibular second molar 6-36 months after impacted third molar extraction. J Clin Periodontol 2002;29:1004-11.
3
To determine the etiologic factors of periodontal pocketing distal to second molars after wisdom tooth extraction
Information not available
Cohort study
Original Article
Level of Evidence
Purpose
Source of Funding
Type of Study/Design
Summary SUBJECTS A total of 158 subjects of Chinese ethnicity were selected for this study. Mean age was 27 (SD, 7 years). Sixty-one subjects were men (39%) and 97 were women (61%). All of the patients had undergone surgical extraction of mandibular third molars at the Prince Philip Dental Hospital in Hong Kong in a period starting 36 months before the beginning of the study in July 1997.
EXPOSURE Mesioangular impaction, ie, impacted lower third molars when the long axes of the third and second molars diverge ≥30°.
MAIN OUTCOME MEASURE Residual periodontal defect on distal surface of second molar.
MAIN RESULTS A mesioangular impacted third molar, when compared with an upright impacted third molar, is associated with, on average, a 1-mm increased pocket depth (P = .001) on the adjacent second molar after extraction. J Evid Base Dent Pract 2003;3:149-50 © 2003 Mosby, Inc. All rights reserved. doi:10.1067/med.2003:57
149
Commentary CONCLUSIONS The presence of isolated deep periodontal pockets distal to second molars is relatively common in a periodontal practice. Third molars are often suspected as the potential etiologic factor for these isolated defects. The present study investigated the association between the radiographic appearance of third molars prior to extraction and the residual probing depths distal to second molars after extraction. The findings indicated that the angular position of the third molar at the time of extraction influenced the periodontal pocket depth distal to the adjacent second molar—a mesioangular impacted third molar was, on average, associated with a 1-mm increase in periodontal pocket depth, as compared with an upright or distally impacted third molar. The findings further suggested that if a mesioangular impacted third molar had a crestal radiolucency, the pocket depth distal of the second molar was, on average, 2.7 mm greater than the pocket depth of a third molar that was upright and that had no crestal radiolucency. ANALYSIS The major strength of this study was the systematic sampling of subjects from a total sample size of 3211 subjects. This approach minimized potential selection biases. A limitation of the current study is that those subjects whose second and third molars were extracted at the same time were deleted from the study. Since extraction of second molars is the worst possible outcome associated with with third molar removal, it is important to incorporate such outcomes in analyses. As the authors indicate, this study could not determine whether the defect was a consequence of the extration itself (socket in the distal area of the second molar) or of the surgical technique used for the extraction (ostectomy). Determining the impact of the surgical removal of third molars on second molars’ periodontal health was beyond the scope of this study. In future studies, consideration should be given to using a nonextraction
150 Kan et al
control group, obtaining periodontal probing measures prior to extraction, and providing a detailed description of the surgical technique used. However, addressing these issues may be challenging. The random assignment of individuals with symptomatic third molars to a nonextraction group may be difficult from an ethical perspective. The authors indicated that in their study a nonsurgical control group was not possible because the Oral and Maxillofacial Surgery Clinic of the Prince Philip Dental Hospital follows a strict protocol for impacted third molar removal whereby only those teeth that are found to cause problems in a patient are removed. In addition, obtaining preoperative probing measures on second molars is sometimes difficult, if not impossible, because of the close proximity of the third molar. Finally, as has been documented in medical surgical procedures,1 dental surgical techniques and expertise can also have a potentially significant effect on outcomes, leading to problems with generalizing the findings. Third molar impactions are common conditions, and their surgical removal is common. Their high prevalence suggests that it is important that future studies evaluate the prognosis for second molars with isolated distal periodontal pockets and, if the prognosis for these teeth turns out to be poor, the type of treatments that may help in improving the prognosis. The current study provided additional evidence on the type of third molar impactions likely to be associated with residual periodontal defects and will help in the design of these future studies. REFERENCE 1. Kantonen I, Lepantalo M, Salenius JP, Matzke S, Luther M, Ylonen K. Influence of surgical experience on the results of carotid surgery. The Finnvasc Study Group. Eur J Vasc Endovasc Surg 1998;15:155-60.
Reviewer: Simone Verardi, DDS University of Washington Seattle
Journal of Evidence-Based Dental Practice September 2003