Oral Health Clinical Research Clinic

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Our Mission and Goals

The Minnesota Oral Health Clinical Research Clinic (OHCRC) supports research projects in the areas of oral surgery, dental materials, restorative procedures, facial pain, neuroscience, caries, periodontal diseases and oral medicine. The center develops and applies advanced technology to prevent, diagnose, and treat diseases affecting the orofacial region. It has cooperative ventures with other related centers, institutes, and universities throughout the U.S. and abroad.

The Clinic maintains a fully equipped multi-purpose research clinic consisting of 10 dental operatories, office space, and data analysis facility. Our staff includes trained and calibrated clinical examiners, study coordinators, a Ph.D. level biostatistician, dental hygienists and dentists. We routinely conduct FDA phase II and III clinical protocols for industry and have the capability and infrastructure to conduct virtually any type of clinical study dealing with oral health care products and procedures.

The Oral Health Clinical Research Clinic at the University of Minnesota School of Dentistry was established in 1990 with grant support from the National Institutes of Health.

The goals of the Clinic are:

  • to translate advances in the basic and applied sciences to the clinical setting
  • to test new technologies in dental care or delivery
  • to link clinical researchers with the dental community
  • to provide research design, consulting and data analysis services to first time and experienced clinical researchers
  • to encourage innovative approaches to clinical oral health research
  • to improve the prevention, diagnosis and treatment of oral diseases

Contact Ms. Patricia Lenton (OHCRC Director) by phone at 612-624-9669 or by email at lento001@umn.edu.
Contact Ms. Carol Dunn (OHCRC Clinic Coordinator) by phone at 612-624-8998 or by email at dunnx008@umn.edu

Study Clinicians with Study Abstracts

Oral Health Clinical Research Clinic (OHCRC)

Division of Periodontology
Developmental and Surgical Sciences
School of Dentistry
7th Floor, Moos Tower
515 Delaware Street S.E.
Minneapolis, MN 55455

Phone: 612-624-8998
Fax: 612-626-2652
E-mail: lento001@umn.edu

For researchers

For patients

Raj Gopalakrishnan, B.D.S., Ph.D.

Raj Gopalakrishnan, B.D.S., Ph.D.

Raj Gopalakrishnan, B.D.S., Ph.D.

Bisphosphonate-Associated Osteonecrosis

Abstract for Bisphosphonate-Associated Osteonecrosis Study:

A. SPECIFIC AIMS
Osteonecrosis of the jaw (ONJ) is a significant and serious oral complication of long-term intravenous bisphosphonate (BP) treatment. The most common presentation of ONJ is painful, exposed bone that occurs in either or both jaws and simulates “tooth-ache” or bone infection. Although over 800 cases have been reported in the literature to date, a major limitation is a lack of knowledge of risk factors and their significance in development of ONJ. Moreover, the epidemiology and pathogenesis of ONJ remains unknown. This is primarily because there have been almost no prospective or matched case-control studies, with the vast majority of reports being either case series or reviews. The resulting information gap significantly impairs the development of preventative and therapeutic modalities for ONJ.

The current project will test the hypothesis that periodontal disease and periodontal pathogens are risk factors for ONJ in cancer patients receiving intravenous bisphosphonates. Our long term goal, which will be tested in a future R01 application, is to characterize key risk factors, and to understand their role in the epidemiology and pathophysiology of ONJ development. The work will be performed in a collaborative research environment. The investigators are skilled in current knowledge and theories of oral and maxillofacial pathology and bone biology (Raj Gopalakrishnan), clinical research and periodontology (Bryan Michalowicz), molecular microbiological analyses of oral samples (Dr. Joel Rudney), and biostatistics (Dr. James Hodges).

To test our hypothesis, the following specific aims will be pursued:

  1. To determine the association between clinical and microbiological measures of periodontitis and risk of ONJ development. Although several reports have speculated that periodontal disease is a major predisposing factor for ONJ development, no studies have been conducted to verify this association. We will perform a thorough periodontal exam in ONJ patients and matched controls to test if periodontitis is associated with ONJ development. Using quantitative PCR, we will also examine the association between ONJ risk and the presence and levels of putative periodontal pathogens – Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, and Treponema denticola - in subgingival plaque samples collected from these same cases and controls.
  2. To determine whether ONJ is associated with increased mucosal invasion of putative periodontal pathogens and Actinomyces species. Putative periodontal pathogens and Actinomyces species have been isolated from ONJ lesions. However, no systematic study using a case-control design has been done to test if these species are more prevalent in ONJ lesions than unaffected intra-oral sites. Previously, we showed that periodontal pathogens (A. actinomycetemcomitans, P. gingivalis, T. forsythia, P. intermedia and T. denticola) can colonize buccal epithelial cells. In a subsequent study of aggressive periodontitis patients, we found that invaded cells provided reservoirs for these pathogens that protected the pathogensfrom elimination following treatment. In the current study, we will use fluorescent in situ hybridization to evaluate the prevalence of these pathogens and Actinomyces species in oral mucosa samples obtained from near the ONJ lesion and from unaffected sites in cases, and from at-risk sites in matched controls.

The expectations from this exploratory case-control study are two-fold: 1) to determine if periodontal disease and periodontal pathogens are risk factors in ONJ development; and 2) identify ONJ patient and control populations that can participate in a prospective study as part of an R01 application to further explore relationships between periodontal disease and ONJ. The results obtained from this application will be significant because they will provide insight into the pathogenesis of a serious oral complication of BP therapy.

In addition, these results will also help us to understand the mechanism of action of BPs and the interaction with identified risk factors.

Estephan J. Moana-Filho, DDS, MS, PhD

Estephan J. Moana-Filho, DDS, MS, PhD

Estephan J. Moana-Filho, DDS, MS, PhD

Study Title: Multimodal Assessment of Sensory Processing and Brain Features in Chronic Orofacial Pain

Project Summary: Chronic orofacial pain disorders may present localized in the mouth such as with persistent dentoalveolar pain disorder (PDAP) or widespread in the head/face/jaw such as with temporomandibular joint and muscle disorders (TMJD). These commonly comorbid disorders have a significant impact on the individual and society. Their mechanisms are poorly understood with evidence suggesting deficient pain modulation and abnormal brain features. PDAP and TMJD patients, when compared to controls, have abnormal sensory/pain processing as well as brain structural and functional differences.

This study will investigate pain modulatory mechanisms and brain functional and structural characteristics using multiple MRI modalities in TMJD patients with and without comorbid PDAP. All measures from patients will be compared to painfree controls. This knowledge will support better understanding of mechanisms involved in TMJD and will support development of mechanistic-based clinical treatments for the patients we serve. Findings from these investigations will likely contribute to our understanding of other chronic pain conditions.

Donald Nixdorf, D.D.S., M.S.

Donald Nixdorf, D.D.S., M.S.

Donald Nixdorf, D.D.S., M.S.

Current Studies Include:

  • Functional Imaging of Trigeminal Pair
  • Quantitative Sensory Testing: Reliability Assessment & Mapping
  • Understanding the Impacts of, and Screening for, Atypical Odontalgia (AO)

Eric Schiffman, D.D.S., M.S.

Eric Schiffman, D.D.S., M.S.

Eric Schiffman, D.D.S., M.S.

Current Study Includes:

  • Reliability Study for – TMJ/Intra-Articular Disorders: Impact on Pain, Functioning & Disability and
  • Recall Study or IMPACT for TMJ/Intra-Articular Disorders: Impact on Pain Functioning & Disability

Temporomandibular muscle and joint disorders (TMJD) are common conditions with a substantial public health burden. Although TMJD patients commonly have temporomandibular joint (TMJ) intra- articular disorders, including disc displacement (DD) and osteoarthritis (OA), the clinical significance of these disorders and their causal relationship to persistent jaw pain and dysfunction are poorly understood. The recently completed Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Validation Project (U01 DEO13331) demonstrated that 1) TMJ imaging is required to diagnose TMJ intra-articular disorders; and 2) cross-sectional data show that radiographically diagnosed DD and OA are significantly associated with jaw pain, jaw functional limitations and disability. It is therefore critical that we assess longitudinally whether these cross-sectional findings can be supported. Given that the available Validation Project cohort was assembled at a cost of $8.2 million, it is unlikely that there will be another similar cohort in the future to investigate the question, one of great significance to the public health: Are TMJ intra-articular disorders causally related to patient-reported outcomes of jaw pain intensity, jaw function and disability? Study participants will be recalled from the Validation Project cohort 9 years after their initial comprehensive examination was completed. Their physical status will be re-assessed, and progression of their intra-articular joint diagnoses will be measured by comparing bilateral TMJ MRI and CT at follow-up to baseline imaging. The subjects' psychosocial status will also be re-assessed along with the primary outcome measures of pain intensity, jaw functional limitations, and disability that are core domains recommended for assessment by Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT). The study will assess when, and under what circumstances, intra-articular disorders progress and whether this progression is associated with increased jaw pain, jaw limitations and disability. We will also determine, as a secondary aim, which baseline biological and psychosocial factors are predictors for progression of TMJ DD and OA at follow-up. The ultimate goal is to determine the degree to which progressive change in intra-articular disorders contributes to pain and dysfunction outcomes, within the context of the biopsychosocial model. This project will provide knowledge necessary for development of evidence-based guidelines for TMJD diagnosis and management, as well as contribute to cost effective imaging and elimination of unnecessary diagnostic radiation.

Wook-Jin Seong, D.D.S., M.S., Ph.D.

Wook-Jin Seong, D.D.S., M.S., Ph.D.

Wook-Jin Seong, D.D.S., M.S., Ph.D.

Current Study Includes:

  • Comparison of Initial Implant Stability of Posterior Maxillary Implants with Bicortical Fixation to Implants Engaging Only the Alveolar Crest

Historically, implant success rates have been very high (>90%). However, posterior maxillary implants still have lower success rates compared to implants placed in other areas of jawbone. In the Sinus Consensus Conference of 1996, Jensen (1998) reported an incidence of implant loss in posterior maxilla of 15%. After 8 years, Buser (1997) had a cumulative success rate of 87% and 95% for posterior maxilla and overall mandible respectively. More recently, the systematic review by Wallace and Froum (2003) had variable implant survival rate of 61.7% to 100% (average 91.8%) for implants placed in maxillary sinuses augmented through a lateral window (direct sinus lift technique) while Emmerich (2005) review on osteotome elevation of the sinus floor (indirect sinus lift technique) showed 96% survival rate at 36 months. Low success rates in the posterior maxilla have been related to the low quality of bone and subsequent low initial implant stability as measured immediately after placement surgery. Therefore, lack of initial implant stability has been well correlated to the early or late failure of the implants. (Esposito 1998; Truhlar 1997)

Primary objectives of this study is to do followings in patients with 7 – 11 mm of residual bone height below the sinus floor in posterior maxilla.

  1. Determine whether dental implant engaging both the alveolar crest cortical bone and sinus floor using stopper drill and self-threading concept (bi-cortical fixation) increases initial implant stability compared to the short implants engaging only alveolar crest cortical bone (uni-cortical fixation) and/or ones engaging both crest and sinus floor but with green stick fracture from osteotome and mallet (indirect sinus lift technique);
  2. Study whether different surgical techniques used, residual bone height, bone density, and length and width of the implants used affect initial implant stability in posterior maxilla;
  3. Compare secondary implant stability (after healing implant stability) of implants fixed bi-cortically, uni-cortically and with indirect sinus lift technique at 2nd stage surgery/6 month healing and 1 year follow-up;
  4. Measure amount of endo-sinus bone formation from 1 year follow-up CT scan and evaluate safety and post-operative complications of bi-cortical fixation and indirect sinus lift techniques reported throughout the follow-up periods.