Andreasen et al (1997) defines impaction as a cessation of the eruption of a tooth caused by a clinically or radiographically detectable physical barrier in the eruption path or by an ectopic position of the tooth. The prevalence of third molar impaction ranges from 16.7% to 68.6%. Common pathologies associated with third molars are pericoronitis, caries of impacted teeth or adjacent tooth, second molar tooth resorption, periodontal bone loss of adjacent tooth and odontogenic cysts. The surgical removal of mandibular third molar is one of the most common procedures done in oral and maxillofacial surgery. Flap design is an important step in third molar surgery.Commonly used flap in surgical removal of third molar are envelope flap and triangular flap with modifications.
A number of classifications have been developed for impacted third molars.The most widely used are;
1. Angulation (Winter, 1926) of the impacted tooth ; Vertical, Mesioangular, Horizontal, Distoangular
2. Relationship of the impacted tooth to the anterior border of the ramus (Pell and Gregory, 1942); Class I: Sufficient space available anterior to the anterior border of ramus for the third molar to erupt.
Class II: Space available is less than the mesio distal width of the crown of the third molar Class III: All or most of the third molar is located within the ramus.
3. Depth of impaction (Pell and Gregory Classification based on relationship to occlusal plane); Position A: The highest portion of the tooth (occlusal plane) is on a level with or above the occlusal line.
Position B: The highest portion of the tooth is below the occlusal line but above the cervical line of the second molar.
Position C: The highest portion of the tooth is below the cervical line of the second molar.
Rationale and justifications of study
The surgical removal of mandibular third molar is one of the most common procedure done in oral and maxillofacial surgery and often associated with pain, swelling, trismus, dehiscence, alveolar osteitis, infection, nerve injury and periodontal tissue damage.Flap design is an important step in this procedure.
The present study is aimed at comparing the envelope and triangular flap in lower third molar surgery based on postoperative outcomes.The study also aims to find does the number of roots and also the relation between level of mesial cusp tip of impacted lower third molar and distal surface of adjacent second molar has any effect on postoperative sequelae.
Although much research was done so far on this topic,further studies were suggested .
Both envelope and triangular flaps are routinely used in lower third molar surgery.So,this study claims no extra medical risks related to the intervention.Patients and investigators bear no extra economic burden in investigations and research.
Objectives
General:
To compare the triangular and envelope flap in surgical removal of vertical and mesioangular impacted lower third molar.
Specific:
To evaluate whether the relation between level of mesial cusp tip of impacted third molar to the distal surface of adjacent second molar has any effect on the post operative outcomes independent of flap designs.
To evaluate the effect of the number of roots of impacted third molar to the postoperative outcomes in third molar surgery independent of flap designs.
Research hypothesis
Null hypothesis: There is no difference between the envelope and triangular flap in terms of post operative outcomes in surgical removal of vertical and mesioangular impacted mandibular third molar.
Alternate hypothesis:There is significant difference between envelope and triangular flap in terms of post operative outcomes in surgical removal of vertical and mesioangular impacted mandibular third molar.
Research design and methodology
Research method Quantitative
Type of study Experimental, double blinded, randomized comparaive study,
Study population Patient visiting department of oral and maxillofacial surgery in TUTH
Study site and its justification Large number of patients visit oral surgery department in TUTH.Most of them visit for surgical removal of impacted mandibular third molar and surgical extraction is commonly performed here.So oral and maxillofacial surgery OPD of TUTH will be ideal site for study as adequate sample size will be available without economic burden to the patient and investigator.
Sampling method Sampling method :Simple random sampling Randomisation will be done by random draw computer method Allocation concealment will be maintained using a sealed opaque envelope.
Sample size
Sample size will be calculated as; Sample size=2SD2(Z
