This study was conducted to compare the periodontal health of labially and palatally impacted maxillary canines with similar mesio-distal displacement, perpendicular distance, and angulation, and to compare them with the contralateral canines that served as control teeth. Two null hypothesis were tested: (1) there are no differences in attached and keratinized gingival widths and gingival thickness between impacted teeth and controls, and (2) there are no differences in attached and keratinized gingival widths and gingival thickness of labially and palatally impacted canines.

When a tooth is embedded in the alveolar bone and fails to erupted into the oral cavity within the expected time, dental impaction occurs. Maxillary canine impaction has been observed more frequently in the palatal position than labial position, and unilaterally than bilaterally. Treatment of these teeth, which consitute a transition between the anterior and posterior dental segments and therefore have a great of importance both from functional and aesthetic point of view, is recommended rather than extraction.

Many complications that have been reported to be faced during the surgical exposure and orthodontic alignment of the impacted teeth are devitalization, external root resorption, damage to adjacent teeth, marginal bone loss, re-exposure of the tooth, and gingival recession. Gingival recession is the apical migration of the gingival margin beyond the cementoenamel junction, resulting in the clinical exposure of the root surface. The term gingival biotype is generally used to describe the thickness of the gingiva in faciolingual/faciopalatinal direction.

Although a large number of existing studies in the broader literature have examined the periodontal health of labially and palatally impacted maxillary canines seperately, limited number of studies compared the labially and palatally maxillary impacted canines. Since one of the factors affecting the posttreatment periodontal health is the initial vertical and horizontal position of the impacted teeth, these studies were observed not provided any information about the pretreatment mesio-distal displacement, perpendicular distance and angulation of the impacted maxillary canines. At this point, this study was conducted to compare the periodontal health of labially and palatally impacted maxillary canines with similar mesio-distal displacement, perpendicular distance, and angulation, and to compare them with the contralateral canines that served as control teeth. Two null hypothesis were tested: (1) there are no differences in attached and keratinized gingival widths and gingival thickness between impacted teeth and controls, and (2) there are no differences in attached and keratinized gingival widths and gingival thickness of labially and palatally impacted canines.

Inclusion Criteria:

• The inclusion criteria were no previous functional orthopaedic and/or fixed orthodontic treatment, complete permanent dentition, aged between 13 and 20 years old at the begining of the treatment, no systemic problems and related medications, good oral hygiene, no gingival inflammation and periodontal diseases, unilateral labially or palatally impacted maxillary canines, indication of surgical uncovering of the impacted maxillary canine using closed eruption technique, presence of normally positioned contralateral maxillary canine, and complete good quality pretreatment and posttreatment records.

Exclusion Criteria:

• Subjects who had fixed orthodontic treatment with teeth extraction, missing teeth adjacent to the canine, and significant distortion between the left and right half jaws in the initial panoramic radiographs were excluded from the study.