Positioning of Teeth Can Affect Phonetics

When restoring anterior teeth, we use our diagnostic wax-up, which is determined by using the

2D and 3D checklist, as our best guess for our provisional restorations.  Once the provisionals are fabricated we then need to evaluate the position of the teeth in the patient’s face and oral cavity.

The position of the upper incisal edges should be at the inner vermillion border of the lower lip or usually referred to as the wet dry line.  This is one of the most reliable guidelines used to determine the incisal edge length.  The importance of the smile line now becomes apparent with the understanding that control of escaping air between the upper incisal edges and the lower lip is necessary for proper phonetics.  If the upper incisal edges are not correctly determined they will not relate to the lip correctly and a strained lip position will be required for making F and V sounds.

Because of variations of lower tooth position, the S sound is not the best determinant, but it serves as an excellent verification method.  Since air can be restricted for the S sound between the lower incisal edges and either lingual surfaces or incisal edges of the uppers, an error on any part of the upper contour might affect the S sound.  Too much space will cause a lisp.  Too little space causes the teeth to bump.

If the contour of the upper cingulum is too bulky, the tongue may bump into it when making T and D sounds.

After evaluating the provisional restorations for phonetics, lip closure path, smile line, esthetics and comfortable anterior guidance then you are ready to cement the provisionals with temporary cement.

As Dr. Peter Dawson says, then once the patient is comfortable and has approved the esthetics, you are then ready to take an impression of the provisionals and tell the laboratory technician to copy the temps.