Dentin exposure in tooth preparations for porcelain veneers: a pilot study

Area of Science:

• Dental Restorations
• Conservative Dentistry
• Tooth Preparation Techniques

Background:

• Current clinical techniques for tooth reduction before porcelain veneer restoration lack consistency in achieving even and conservative enamel reduction.
• The most enamel-sparing preparation technique remains undetermined.

Purpose of the Study:

• To evaluate the effectiveness of three clinical techniques (dimple, depth groove, freehand) in creating intraenamel preparations for porcelain veneers.
• To examine the relationship between overpreparation and potential dentin exposure.

Main Methods:

• Three groups of five extracted maxillary central incisors were prepared to a 0.5 mm depth using dimple, depth-groove, and freehand methods.
• X-ray microtomography scanning and specialized software were used to visualize and quantify enamel and dentin surfaces.
• Coordinate metrology produced color-coded depth maps; statistical analysis (Kruskal-Wallis test) assessed enamel conservation differences.

Main Results:

• No statistically significant difference (P=.07) was found among the three techniques in conserving enamel.
• The dimple technique demonstrated a trend towards greater mean enamel preservation (77.5% ± 14.2) compared to depth-groove (50.1% ± 17.5) and freehand (76.8% ± 24.4) methods.
• Preparation depths were generally within the enamel layer (0.4-0.6 mm), with exceptions noted in the cervical region.

Conclusions:

• The three tested clinical techniques (dimple, depth groove, freehand) did not show significant differences in their ability to conserve tooth enamel.
• Further research is warranted to definitively establish the most conservative technique for intraenamel preparation.