Difficulty in pronouncing s,sound is generally caused by insufficient space between upper
lingual surface and lower facial and incisal edge.Reduction of upper
lingual surface may solve the problem.Indentation of tongue tends to occur in lateral margin, which may be associated with overcontour of lingual surface of posterior teeth. If posterior teeth are implant supported, the restorative dentist may need to use angled abutment or ucla abutment to change the angulation of abutments.