The document discusses a study that assessed the effect of surgically removing impacted mandibular third molars (M3) on the adjacent second molars (M2). 78 young patients underwent M3 removal, and probing depths and attachment levels were measured at baseline and 6 months post-op. The results showed a statistically significant decrease in probing depths and improvement in attachment levels over time. Male patients and those with submucosally impacted M3 experienced greater reductions in probing depths. In conclusion, surgical removal of impacted M3 had no negative effects and potentially positive periodontal benefits for the adjacent M2.

1. Surgical removal of third
molars and periodontal
tissues of adjacent second
molars
Petsos H et al.
J Clin Periodontol, may 2016

2. Introduction
 From a periodontal point of view the clinical
decision for surgical removal of impacted
mandibular third molars (M3) presents a clinical
challenge.
 As a result of the surgical M3 removal
periodontal pockets may arise or disappear distal
to the second molars (M2).
 This potential effect of surgical tooth removal
should be considered, especially since the
extraction of M3 is the most commonly
performed procedure within oral surgery.

3. Aim
 The aim of this study was to assess the effect of
the surgical removal of asymptomatic impacted
mandibular M3 on the adjacent M2 in a younger
patient population by measuring probing pocket
depths (PPD) and probing attachment levels (PAL)
at baseline and 6 months later as well as
examining the influence of possible cofactors on
any changes observed.

4. Material & Method
 All M3 removed (either 48 or 38) were completely
impacted (entirely within the bone) or submucosal
(completely below the mucous membrane), had a close
positional relationship with the adjacent M2 and no
contact with the oral cavity.
 The impacted M3 were not classified anymore, because
in most of the cases a type of angulation was not really
recognizable due to the missing or poor suggestable
root growth of the M3 in the preoperative panoramic
radiographs.
 For a further subclassification of impacted M3 a larger
sample size would have been required to accomplish
statistically significant results for each subclass.

5.  Completed root growth of the adjacent M2 was a
prerequisite.
 An exclusion criterion was the non-fulfillment of
the above criteria, the presence of systemic
disease (e.g. Diabetes mellitus, cardiovascular,
kidney, liver or lung disease), withdrawal of
written consent, or failure to appear at the follow-
up appointment.
 All M3 were removed because of orthodontic
reasons.

6. Clinical parameters
 The clinical parameters examined at baseline and at 6
months after surgery were the Plaque Index (PlI) and
Gingiva Index (GI), probing pocket depth (PPD) and
probing attachment level (PAL).
 All measurements were obtained by an investigator with
a periodontal probe calibrated in millimetres (UNC 15).
 Measurements were obtained at six sites around the
M2 (mesiobuccal, buccal, distobuccal, distolingual,
lingual, mesiolingual).

7. Surgical procedure
 An oral surgeon performed the surgical removal of the
M3 (n = 78) under local anaesthesia or general
anaesthesia.
 First, a mucoperiostal flap was reflected on the basis of
a marginal incision on the M2 with a distovestibular
releasing incision.
 The wisdom tooth was horizontally dissected with rotary
instruments using continuous sterile saline irrigation
and removed.

10. Result
Patient population
 Of the initially 91 patients who met the inclusion criteria for this
study, the data of 78 patients with 78 extracted M3 were ultimately
included in the statistical analysis.
 Of the 78 patients, 29 were male and 49 were female. Their mean
age was of 16.0 ± 2.0 years.
 Seventy-four of the patients were non-smokers, whereas four were
smokers. Of the total of 148 M3 removed 78 were used for statistical
analysis.
 58 teeth were classified as submucosal and 20 teeth were fully
impacted. In 70 patients, both mandibular M3 were removed; in eight
patients, only one side of the jaw received surgery.

11. Plaque Index and Gingiva Index
 GI values were assigned to groups for “no
inflammation” (code 0) and “inflammation” (codes 1, 2
and 3).
 The same was done with the PlI values for “no plaque
formation” (code 0) and “plaque formation” (codes 1, 2
and 3).
 The subsequent analysis of changes over the follow-up
period showed an average improvement for the GI, but
deterioration for the PlI. These changes were not
statistically significant (p ≥ 0.05).

12. Probing depths and attachment levels
 Looking at the individual averaged
measurement points over all teeth,
postoperatively exhibit the lowest average
PPD and PAL both mesiolingually and
mesiovestibularly, with a slight increasing
trend in a distal direction.
 PPD and PAL decrease from baseline to 6
months were statistically significant (p <

13. Cofactors
Sex
 Male patients exhibited a greater PPD reduction
(0.8 mm) and PAL improvement (0.6 mm) than
female patients (PPD: 0.6 mm; PAL: 0.4 mm).
 However, the study failed to proof these mean
differences as statistically significant.

14. Complications
 The following complications (n = 20) were reported:
 intense pain for more than 1 day after surgery (n =
12)
 postoperative infection (infiltrate or abscess) (n = 5)
 wound dehiscence (n = 3)
 secondary bleeding (n = 0)
 nerve damage (n = 0).

15. Suture material
 The use of different suture materials for wound closure
after the osteotomy of the respective M3 had no
statistically significant effect on PPD and PAL changes.
 The improvement in PAL was more pronounced when
using the monofilament suture material than when using
the pseudomonofilament silk.
 Looking at the average PAL, this means an
improvement of 0.5 mm after 6 months with the
monofilament material and 0.4 mm with the silk
material.

16. Type of impaction
 Finally, the influence of the preoperatively determined type of
impaction of the removed M3 on changes in PPD and PAL
was analysed.
 The type of impaction was classified as submucosal (fully
covered by oral mucosa) or as impacted (completely within
the bone).
 When looking at PPD averages, the type of impaction had a
statistically significant effect (p = 0.039). The average
reduction in PPD was 0.4 mm greater in submucosal than in
fully impacted M3.

17. Discussion
 This study was undertaken to investigate whether the surgical
removal of M3 in young, healthy patients, has a negative or a
positive effect on the periodontal tissue of the adjacent M2
and whether any additional cofactors correlate with these
changes.
 Prophylactic M3 surgery is often performed because of a
possible disease (cysts and tumours) development, reduction
of the risk of mandibular angle fracture, increased difficulty of
surgery with increasing age.
 This study provides the results of changes in PPD and PAL
after M3 surgery as possible periodontal indications for a
prophylactic removal.

18.  The six-months follow-up period was chosen because
available data show that a major part of the periodontal
healing process distal to the M2 is completed after just 3
months.
 Patient age has been mentioned as a risk factor in several
studies, which is why a young patient population was
recruited for this study.
 Young patients take benefit from early surgical M3 removal
compared to older patients in different ways: intraoperative
risks (as nerve damage) and bone defects are minimized,
because in older patients the root growth of M3 is completed
and they are often more angulated than in younger patients.

19. Conclusion
 Within the limitations of this study the following conclusions may be
drawn:
• Irrespective of the reason for M3 removal a pre-surgical risk
assessment has to be conducted.
• The surgical removal of impacted or submucosal M3 has no negative
effect on the periodontal tissues of the adjacent M2.
• It could be shown that the investigated effect is subject to
multifactorial influences, which explains the controversial data
situation.
• Looking only at “pathological” sites with on average preoperative
probing depths ≥4 mm, removal of asymptomatic M3 at a young age
may have a beneficial effect on the periodontal conditions on the
distal part of M2 from a purely periodontal point of view.

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