Postoperative hypersensitivity (POH) is a problem for many patients as determined by the recent Practitioners Engaged in Applied Research and Learning (PEARL) study of POH following occlusal caries restoration. The objectives of this two-armed randomized comparative effectiveness research trial (RCERT) are to determine whether adding a resin modified glass ionomer liner (RMGI) reduces POH in dentin bonded Class I resin based composite (RBC) restorations, and to identify other factors (putative risk factors) that are associated with increased POH.

The primary outcome of this study is the reduction/elimination of restoration POH as measured by clinical assessment (air stream) and patient-reports.

Outcomes will be ascertained via the following specific aims:

Specific Aim 1: To compare the reduction of hypersensitivity of study teeth by clinical measurement (air drying) and by patient-reported outcomes among the two treatment groups at three points in time: prior to restoration and at one and four weeks postrestoration.

Specific Aim 2: To identify putative risk factors for POH (or factors associated with differences in POH) including: preoperative caries stage measured by the proposed American Dental Association (ADA) Caries Classification System (CCS), lesion depth as measured on the preoperative radiograph, dentin caries activity ranked on opening the lesion, preparation depth, and patient sleep bruxism status.

Inclusion Criteria:

1. Presence of solely adult dentition ages 15 to 60 (The upper age of 60 years is selected since the pulp space is limited and POH is less likely above this age).
2. Presence of one or more permanent posterior teeth (in different quadrants, with third molars excluded) with the clinical diagnosis of new Class I caries extending into dentin with or without radiographic confirmation. Up to 4 teeth (one per quadrant) may be enrolled. If there is more than one occlusal lesion in a quadrant that meets the inclusion criteria the patient is not eligible for inclusion in the study. Only one tooth per quadrant can be treated during the 4 weeks of this study.
3. Lesion depth, if visible on radiograph, must be ≤1/2 the distance from the Dento-Enamel Junction (DEJ) to the pulp and the radiograph cannot be more than 9 months old.
4. The tooth must be in occlusion with a natural tooth.
5. A resin-based composite restoration would be the standard of care for the lesion.
6. The tooth must be free of evidence of a pulpitis (no report of lingering pain associated with any stimulus).
7. Subjects must be available for contact for at least four weeks post-treatment.
8. Subjects willing and able to understand and sign the IRB-approved informed consent form and for individuals under the age of 18, the parental / guardian assent form.
9. Subject's baseline score on the NPAS must be ≥3 for air and/or cold stimulation but not exhibit pain lasting more than approximately four seconds which is known as "lingering pain"
10. Gingival Index of less than or equal to 2.

Exclusion Criteria:

1. Individuals in which the second molars are not fully erupted.
2. Teeth with a mobility of 2 or greater, or inflamed gingival tissues.
3. Existing restoration(s) on the same tooth.
4. Teeth that have been clinically assessed to be fractured.
5. Tooth is an abutment for a removable partial denture.
6. Tooth with subgingival calculus, unless removed during the treatment visit.
7. Subjects undergoing active orthodontic treatment. Use of retainers is allowed.
8. Subjects currently enrolled in or who have completed in the past month a tooth bleaching program.
9. Subjects with prior reaction or inability to tolerate any of the dental products being used, such as severe topical or hypersensitivity reaction.
10. Subjects under treatment for medical disorders including: dementia, Parkinson's disease, severe depression, severe anxiety, and any other medical condition that, in the opinion of the P-I, would affect the subject's judgment of postoperative hypersensitivity and ability to understand the informed consent process.
11. Subjects in another ongoing dental research study.