Update on Research in the PEARL Network

Ronald G. Craig, DMD, PhD; Frederick A. Curro, DMD, PhD; Donald Vena, BS; Van P. Thompson, DDS, PhD

The PEARL (Practitioners Engaged in Applied Research and Learning) Network is one of three national dental practice-based research networks that enable member practitioner investigators (PIs) to conduct clinical research within their own practices. The Network is supported by a $26.7 million grant from the National Institute of Dental and Craniofacial Research (NIDCR). Research ideas are generated by PEARL PIs and developed and vetted into formal research protocols through the administrative center located at the New York University College of Dentistry; the data coordinating center, the EMMES Corporation of Bethesda, Maryland; an external scientific advisory board; and NIDCR. Protocols are designed to be time efficient and to minimally impact the flow of patient care within the PI's practice. Both the practice and study subjects are compensated for their time in these studies. Network PIs further participate in reporting the results of PEARL research at national and international meetings and of authorship in clinical and scientific papers.

Studies conducted within the PEARL focus on questions of direct clinical relevance encountered in the day-to-day practice of dentistry. Studies range from simple surveys to effectiveness research to randomized controlled clinical trials. The PIs are free to select the type and number of studies in which they wish to participate. They are assisted by a team of professionally trained clinical research coordinators who help initialize the study, facilitate the flow of data between the practice and the data coordinating center, and ensure data quality generated by the site. The clinical research coordinators are always available to help when questions regarding the study arise.

Ongoing studies in the PEARL Network include:

• Hypersensitivity after the placement of resin-bonded composite restorations.
• Risk profiles associated with osteonecrosis of the jaw.
• Outcomes of complete vs partial removal of caries in deep carious lesions.
• Endodontic treatment outcomes in general practice.
• Use and effectiveness of analgesics in dental practice.
• A randomized clinical trial on the treatment of hypersensitive noncarious cervical lesions.

Interim results of two ongoing studies further illustrate the types of clinical questions being addressed in the PEARL Network. Postoperative hypersensitivity (POH) has been associated with the placement of resin-based composite restorations; however, little has been published on the incidence and severity of POH after placement of this common restoration. This study is designed to determine:

1. the incidence and severity of POH in patients who receive Class I resin bonded restorations;
2. the association between restoration depth and width, dentin caries activity, cavity lining, bonding materials, and techniques on POH; and
3. the perceived quality of life after the placement of a resin-based composite restoration.

Interim data analysis of 648 teeth in 583 participants revealed that, before treatment, a large number of patients had sensitivity from these relatively shallow lesions. The amount of pretreatment sensitivity was related to caries activity and not to the preparation depth. An increased incidence of POH appeared to be associated with one type of cavity disinfectant. When enrollment reaches the target of 610 people, it will be possible to determine the effects of lining and dentin-bonding materials on POH. At the April 2008 annual meeting of the American Association of Dental Research in Dallas, Texas, the interim results demonstrating 18% of patients with no preoperative hypersensitivity but developed POH after restoration were reported. A manuscript has been submitted for publication.

Most endodontic therapy is provided in general practice settings. However, most studies documenting success rates of endodontic therapy have been conducted in specialty practices or academic centers. Given the question of whether extraction and placement of a dental implant has a better long-term prognosis than conventional endodontic therapy, this study will determine the 3- and 5-year outcomes and risk factors associated with success and failure of endodontically treated teeth in general dental practices. As of January 12, 2009 , 942 participants have been enrolled in this study. An interim analysis suggests that endodontic and restorative failures are significantly higher than anticipated. Interim results were presented at the July 2008 International Association of Dental Research meeting in Toronto , Canada , and a manuscript describing these results has been submitted for publication.

Further details about these and other PEARL Network studies will be presented in Compendium regularly. To learn more about the PEARL Network, please go to www.pearlnetwork.org.

About the Authors

Ronald G. Craig, DMD, PhD
PEARL Executive Management Team
Director, Regulatory Affairs and Clinical Investigations
Bluestone Center for Clinical Research
New York University College of Dentistry
New York, New York

Frederick A. Curro, DMD, PhD
PEARL Executive Management Team
Associate Professor, Department of Basic Sciences and Craniofacial Biology
Department of Periodontology and Implant Dentistry
New York University College of Dentistry
New York, New York

Donald Vena, BS
PEARL Coordinating Center Principal
The EMMES Corporation
Rockville, Maryland

Van P. Thompson, DDS, PhD
PEARL Executive Management Team
Chair of Biomaterials and Biomimetics
New York University College of Dentistry
New York, New York