Wear of Enamel Against Polished Zirconia Crowns

To participate in this study a crown will need to be place on one of the back teeth. This
generally occurs when the back tooth has a big filling and there is a risk for fracture of
the tooth or a root canal has been performed on the tooth. An initial x-ray of the tooth and
the surrounding teeth will be done to make sure that there is enough bone supporting the
tooth that will be crowned.

A receive local anesthesia will be used in the area where the crown will be made. The tooth
area may need to be build-up with a filling material if there is not enough tooth structure
remaining. Once this happens, then a high-speed drill will be used to a grind down of the
tooth material using to a make smaller size of the original tooth. A small thread will be
used to make space between the gums and tooth so an accurate replica of the tooth can be
made. A temporary crown will be made to go over the prepared tooth and will cement until the
final crown is ready to be cemented.

The extra procedures will be done to measure bite force to see how much force is exerted with
the teeth. Other extra procedures include the six month and yearly impressions as well as
scanning of your teeth to aid in the measurement of wear.

Participants will be randomly assigned (much like the flip of a coin) to receive either a
crown that has metal in it or a crown that is all-ceramic. Both of these materials are
considered standard of care in dental practice.

Inclusion Criteria:

- Subjects must be over 21 years of age and in good overall health. No contraindications
to dental treatment are present

- Subjects must be in good overall good dental health and are at a low caries risk, with
no active tooth decay (caries), and no periodontal disease. Periodontal pocket depths
on all remaining teeth are not greater than 4 mm

- Subjects must have no existing temporomandibular disorder, (e.g. clicking, popping,
pain on opening) or parafunctional habits (e.g. bruxism, clenching)

- Subjects must need a crown on either a first or second premolar or first or second
molar in any arch. Abutment teeth must be restorable and have a crown:root ratio of at
least 1:1. Abutment teeth must have a full complement of opposing non-restored or
minimally restored natural teeth. Minimally restored means the teeth contain no
restoration greater than a Class II amalgam restoration. The opposing arch must not
have a full coverage restoration or a partial denture. The contralateral tooth and its
antagonist are present

- Subjects must exhibit good oral hygiene and compliance with oral hygiene instructions
as determined by the amount of plaque present on tooth surfaces

- Subjects must exhibit a normal flow of saliva. Subjects with any medical pathologies
that limit salivary flow volume or who require a chronic intake of medications that
minimize flow of saliva will be excluded from the study

- Subjects must be willing to pay $500 for the clinic incidentals and they must be
compliant with yearly appointments

Exclusion Criteria:

- anything that does not meet inclusion criteria