Aesthetic and functional aspects of incisal guidance: a systematic review

This systematic review of the literature aims to assess the scientific evidence regarding incisal guidance from both aesthetic and functional perspectives. The ultimate aim was to provide the clinician with evidencebased guidelines to assist in routine dental practice. The Medline database (PubMed) was searched for relevant articles using the keywords “incisal guidance” and “anterior dental guidance” and no time constraints. Types of studies selected were randomised clinical trials (RTCs); prospective, retrospective and transversal studies; controlled clinical trials; and comparative studies. This search furnished 252 articles, but only eight were deemed suitable for review after application of the inclusion and exclusion criteria. The final sample contained no RCTs, comprising only transversal clinical trials. No study included a previous sample size estimation, and none performed method error analysis. None of the subjects analysed dropped out. Only one article featured blind measurements, and only one a randomly selected sample. The description of the characteristics of the test subjects was judged to be adequate in five studies, intermediate in one, and poor in two. The quality of the articles was deemed to be low in three cases, and intermediate in the remaining five. Given the heterogeneity of the articles deemed suitable for review and the poor statistical power of several, it was not possible to formulate evidence-based guidelines. Nevertheless, several indications useful for clinical practice are suggested, particularly as regards combined orthodontic-restorative treatments.