Soft tissue changes inconclusive in Class II division 1 patients treated with Activator and Bionator appliances

Medline, Medline In-Process and other non-indexed citations, Lilacs, PubMed, Embase, Web of Science and all evidence-based medicine reviews were searched. The reference lists of the retrieved articles were also searched by hand for possible missing articles. Authors were contacted to obtain additional information if necessary.

For inclusion, an article had to satisfy the following criteria: they should be clinical trials with a comparable untreated control group; facial soft tissue changes were evaluated through lateral cephalograms; Activator and/or Bionator functional appliances were used to correct Class II division 1 malocclusions; no syndromic or medically compromised patients were included; none were individual case-reports or series of cases; there was no surgical intervention; and only a removable functional appliance was used.

Screening of eligible studies was independently made by both authors and their results were compared: discrepancies were settled through discussion. In the case of the Lilacs database, evaluation was by one author alone because of language limitation. Eligible studies were independently evaluated by both authors using a methodological scoring process which was developed to identify which selected studies would be most valuable.

The search identified 30 articles, of which 11 met the inclusion criteria. Only one of these was a randomised controlled trial. Five studies evaluated the soft tissue changes after use of an Activator appliance. No changes in the naso-labial and labio-mental angles were observed, but a mild protrusion of menton was reported. Neither the tip nor the base of the nose underwent any change. Contradictory results were found regarding the position of the upper lip, the lower lip and menton. Contradictory changes in upper lip thickness and length were also reported, but no changes in the lower lip or soft tissue menton were noted. Six studies evaluated the soft tissue changes using a Bionator. Contradictory results were reported for the facial angles. No studies reported a significant naso-labial angle change. Total face height and lower face thirds were augmented. Contradictory results were found for the antero-posterior position of the upper lip, lower lip and soft-tissue pogonion. A vertical increase was reported for upper lip, lower lip and soft tissue menton measurements.

Based on the available evidence, a significant amount of controversy regarding the soft tissue changes produced by the Activator and the Bionator exists. Soft tissue changes that were reported as being statistically significant were of questionable clinical significance.