Commentary

The issue of incisor proclination outside their “normal” dentoalveolar envelope as a source of gingival recession has been discussed for years. Fixed class II correctors have been commonly criticised for “dumping” the lower incisors forward in an attempt to camouflage large overjets frequently associated with class II division 1 malocclusions. This review offers the first organised attempt to shed some light on this topic. Commonly accepted guidelines to conduct systematic reviews were followed. Although it is broadly believed that lower incisor proclination leads to gingival recession, there are very few clinically studies that have actually investigated this and unfortunately the review results are not clear cut. Although an association was found between incisor inclination and gingival recession, the magnitude cannot be considered clinically significant.

Clinicians should not automatically assume that an incisor proclination will generate a correlated gingival retraction. Factors that should be considered as red flags before attempting to procline incisors are the presence of gingival retraction before orthodontic movement, poor oral hygiene, gingivitis and a thin gingival/bone biotype. The combination of some or all of these factors in addition to proclination of incisors will likely produce some degree of gingival recession.

Some limitations can be identified in this systematic review. The title implies an analysis of any orthodontic tooth movement but the review focused only on lower incisor movement. All included studies were of retrospective nature and therefore commonly expected biases associated with this type of studies cannot be dismissed. There was also no discussion about the aetiology of the gingival recession per se.

Analysing the included studies, some considerations that should be taken into account in future studies can be pinpointed. It is important to consider how the different tooth movement types (translation and/or tipping) could affect the periodontal tissues supporting the lower incisors. Measurement from dental casts can be misleading because factors such as extrusion, wear, crown fracture, attrition or tooth restorations are difficult to control. Pre-treatment factors such as gingival status, periodontal history and/or previous trauma should be considered. Recession during orthodontic treatment may not be progressive and the response may be more related to individual variation in the quality of the gingival tissues around specific dentoalveolar areas.

Practice points

  • Clinicians should not automatically assume that an incisor proclination will generate a correlated gingival retraction.

  • While not discussed specifically, presence of gingival retraction before orthodontic movement, poor oral hygiene, gingivitis and/or a thin gingival/bone biotype in addition to proclination of incisors will likely produce some degree of gingival recession.