Flap design and suturing are critical components of surgical dentistry due to their role in exposing otherwise inaccessible teeth or osseous structures during oral surgery. Under the mentorship of Dr. Jeffrey A. Elo at the Western University of Health Sciences, I investigated how the use of a novel incision and flap design with primary closure can drastically reduce the rate of alveolar osteitis (“dry socket”) following mandibular third molar removal, a phenomenon which reportedly affects 10-45% of patients.
Because alveolar osteitis commonly results from the loss of the blood clot from the extraction socket, we devised a new flap design that we called a “second molar mesial papilla-sparing marginal incision with distobuccal release,” or MPMI. The incision begins approximately 12mm posterolaterally to the distobuccal cusp of the second molar where a #15 blade incises through mucosa and periosteum down to bone. The incision is made to the distobuccal line angle of the second molar and is carried around its facial surface to the mid-facial sulcus. The distobuccal release negates the necessity of extending the incision anteriorly (as seen in an envelope flap) or vertically (as seen in a modified triangular flap) by decreasing the flap tension posterolaterally. It also provides ample visibility for surgical access as well as a more linear and easily accessible incision that can be primarily sutured (double-pass of the suture) to close the flap – protecting the blood clot that forms within the socket and while preventing food debris from entering the incision site.
We recruited 210 patients with bilateral, symmetric partial or full bony impacted mandibular third molars and divided them into three equal and randomized groups of 70, accounting for gender, tobacco use and contraceptive use. For each patient in group one, one randomly selected third molar was removed using a traditional modified triangular flap (MTF) while the contralateral molar was removed using MPMI with double-pass single-layered primary closure (MPMI-2X). Similarly, for patients in group two, one molar was removed using the traditional envelope flap (EF) while the contralateral molar was removed using MPMI-2X. All extraction sites accessed with MTF or EF in groups one and two were closed using two interrupted sutures, as is standard practice with those incisions. In group three, while each patient was treated via MPMI bilaterally, one of the randomly selected molar sites was closed using a single-pass, single-layered primary closure (MPMI-1X) while the contralateral had a double-pass, single-layered primary closure (MPMI-2X). Follow-up evaluation was conducted five to seven days later by an independent oral and maxillofacial surgeon to assess the presence or absence of complications such as infection, wound dehiscence and alveolar osteitis.
No sites treated with MPMI-2X developed alveolar osteitis compared to EF and MTF sites, which demonstrated a 15.6% and 9.4% rate of alveolar osteitis, respectively (p < 0.0001). EF sites demonstrated a 25% rate of dehiscence and 9.4% rate of infection, while MTF sites showed 31.3% rate of dehiscence and 6.3% rate of infection. The complication rates seen in MTF and EF were significantly higher but statistically indistinguishable from each other. Interestingly, the rate of complications dropped even further when a double-pass, single-layered primary closure was utilized. Only two MPMI-2X sites developed post-operative infection and only 4.1% of the MPMI-2X sites demonstrated dehiscence, which was deemed statistically significant.
When we consider potential patient discomfort and possible economic losses from extended post-operative clinic appointments, the use of MPMI may be a viable alternative compared to the more traditional vertical releasing or non-papilla-sparing incisions. Based on our findings, we recommend the use of a few extra minutes to meticulously obtain double-pass, single-layer primary closures to reduce complications such as dry socket, infection and wound dehiscence.
~ Brian Sun, WesternU ’17