Comparison of two different flap designs in the surgical removal of bilateral impacted mandibular third molars

Abstract

The purpose of this study was to compare the effects of flap design on the postoperative sequelae of pain, swelling, trismus and wound dehiscence after surgical removal of bilateral impacted mandibular third molars (M3). 20 patients aged 20–30 years who required removal of bilateral impacted M3 were included in the study. Maximum interincisal opening and facial measurements were recorded preoperatively. Bayonet flap was used on one side and envelope flap on the other side for the removal of impacted M3. The effect of flap design on pain, swelling, trismus and wound dehiscence was evaluated postoperatively. Pain and wound dehiscence were significantly greater in the envelope flap group compared with the bayonet flap group ( P < 0.05). No significant difference in postoperative swelling and trismus was found in either group ( P > 0.05). The bayonet flap was superior to the envelope flap for postoperative pain and wound dehiscence. There was no difference in postoperative swelling and trismus between the two groups.

The surgical removal of an impacted mandibular third molar (M3) is a common procedure associated with various techniques and anecdotal opinion. The techniques used for incision in the mucosa and reflection of the mucoperiosteal flap affect the intensity and frequency of postoperative complications in M3 surgery . This study compares two flap designs, the bayonet flap and the envelope flap, and their effect on the postoperative sequelae of pain, swelling, trismus and wound dehiscence after surgical removal of bilateral M3.

Materials and methods

20 patients (3 male and 17 female), aged 20–30 years (mean 25 years), were selected for this study. Inclusion criteria consisted of: patients with no history of medical illness or medication that could influence the course of postoperative wound healing; and healthy dental and periodontal status with no local inflammation or pathology at the time of tooth removal.

An attempt was made to include only those bilateral M3s that were of comparable technical difficulty, positioning and angulation as seen on panoramic radiographs.

Preoperatively, intraoral periapical, panoramic radiographs and informed consent were obtained and the following parameters were evaluated. The maximum interincisal mouth opening was recorded using Vernier calipers as the distance between the upper and lower central incisors. The facial measurements were recorded by a thread, which was transferred to a standardized calibrated scale. The horizontal facial measurement was taken as the distance from the corner of the mouth to the attachment of the earlobe. The vertical measurement was taken as the distance from the outer canthus of the eye to the angle of the mandible by palpating and marking the inferior border . The facial measurement was calculated as :

Horizontalmeasurement+verticalmeasurement2
Horizontal measurement + vertical measurement 2

A standard surgical protocol was followed. One surgeon, experienced in the use of both the flap designs, performed the surgery while another carried out the evaluation. Prophylactic intravenous antibiotic, amoxycillin 1 g and clavulanic acid 200 mg (Augmentin 1.2 g; GlaxoSmithKline Pharmaceuticals Limited, Mumbai, India) and tablet ibuprofen (Brufen 600 mg; Abbott Group of Companies, India) was given 1 h before surgery. 0.2% chlorhexidine rinses were given to all patients for 30 s before the procedure. The local anaesthetic used was 2% lidocaine with 1:200,000 adrenaline (Xylocaine ® ; Astra Zeneca Pharma India Limited, Bangalore, India). A bayonet flap was made on one side and an envelope flap on the other. Side selection was randomized by systematic allocation and both the patients and evaluator were blinded to the flap groups. The minimum time interval between the two sides was 1 month. The envelope flap incision started on the ascending ramus, following the centre of the M3 shelf to the distobuccal surface of the second molar and then extended as a sulcular incision to the mesiobuccal corner of the first molar ( Fig. 1 ) .

Fig. 1
Incision used for the envelope flap.

The bayonet flap incision started on the ascending ramus, following the centre of the M3 shelf to the distobuccal surface of second molar and then extended as a sulcular incision up to the midpoint of the buccal sulcus of the second molar, followed by an oblique vestibular extension ( Fig. 2 ) . After exposing the surgical site, ostectomy was carried out using a bur technique and the tooth was sectioned as necessary. The flap was approximated with 3-0 mersilk (Ethicon). The duration of surgery was noted from the time of incision until the insertion of the last suture ( Table 1 ). In case of the bayonet flap, a suture was also placed on the vertical limb. All patients were prescribed ibuprofen 600 mg tds for 5 days and 0.2% chlorhexidine mouth rinses for 7 days postoperatively. Pain, swelling, trismus and wound dehiscence were noted on postoperative days 1, 3, 7, 14 and 30. Pain was evaluated by the patient on a daily basis for 7 postoperative days or until the patient was pain free using a visual analogue scale (VAS) calibrated from 0 to 10,with 0 as no pain, 1–3 as mild pain, 4–6 as moderate pain, 7–9 as severe pain and 10 as worst pain. To facilitate the use of VAS by the patients, the end points were marked as ‘no pain’ and ‘worst pain’. Legends were placed over different parts of the scale as shown in Fig. 3 .

Fig. 2
Incision used for the bayonet flap.

Table 1
Mean duration of surgery in both envelope flap and bayonet flap groups.
Total no. of patients Env Bnt
Mean duration of surgery (min) Mean duration of surgery (min)
20 37.50 28.85

Env = envelope flap.
Bnt = bayonet flap.

Fig. 3
To facilitate the use of VAS by the patients legends were placed over different parts of the scale.

Facial swelling (%) was calculated as :

PostoperativemeasurementpreoperativemeasurementPreoperativemeasurement×100
Postoperative measurement − preoperative measurement Preoperative measurement × 100

Trismus (%) was calculated as :

PreoperativemeasurementpostoperativemeasurementPreoperativemeasurement×100
Preoperative measurement − postoperative measurement Preoperative measurement × 100

The relationship of tooth angulation, eruption status and duration of surgery with postoperative sequelae (pain, swelling and trismus) was evaluated on postoperative days 1 and 7. Wound dehiscence was noted on the seventh postoperative day. The wound was considered to be dehisced if there was gaping along the entire incision line . If found to be positive, the wound was not re-sutured and the time taken for complete wound healing was noted. Postoperative complications in any of the groups were noted and treated.

Statistical analysis

Data were subjected to different types of statistical analyses such as χ 2 , Karl Pearson test (KP), analysis of variance approach (ANOVA) and Student’s t -test. Statistical analysis was carried out by computer-developed software on MS DOS and windows based R language.

Results

Pain

Statistical analysis using the χ 2 test revealed significant difference ( P < 0.05) in the number of patients reporting severe pain in the envelope flap ( n = 14; 70%) and the bayonet flap ( n = 4; 20%) group on the first postoperative day. In the envelope flap group, pain subsided completely in five patients (25%) by day 7 and in the remaining 15 patients (75%) in 7–14 days. In the bayonet flap group, pain subsided in 15 patients (75%) by day 7 and in the remaining five patients (25%) in 7–14 days. This difference was statistically significant ( P < 0.05) ( Table 2 and Fig. 4 ). On postoperative days 14 and 30, 100% of patients reported no pain in both the flap design groups.

Table 2
Comparison of pain scores in the envelope and bayonet flap group.
Post op. days Type of flap No. of patients in pain category ( n ) χ 2 P
None Mild Moderate Severe
1 Env 1 1 4 14 11.050 * <0.05
Bnt 1 6 9 4
2 Env 1 4 7 8 3.202 ns >0.05
Bnt 1 6 10 3
3 Env 2 4 10 4 1.537 ns >0.05
Bnt 2 7 9 2
4 Env 3 6 8 3 4.429 ns >0.05
Bnt 4 10 6 0
5 Env 3 10 6 1 3.600 ns >0.05
Bnt 7 10 3 0
6 Env 4 14 2 0 2.620 ns >0.05
Bnt 8 9 3 0
7 Env 5 13 2 0 10.556 * <0.05
Bnt 15 5 0 0
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Feb 8, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Comparison of two different flap designs in the surgical removal of bilateral impacted mandibular third molars
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