Multivariate analysis of factors influencing outcomes of regenerative therapy: A retrospective study

Shyuan-Yow Chen, DDS,(a) Hom-Lay Wang, DDS, MSD,(b) Gerald N. Glickman, DDS, MS,(c) Yu Shyr, PhD,(d) and R. Lamont MacNeil, DDS, MdentSc(e)

(a)Department of Dentistry, Cathay General Hospital, Taipei, Taiwan, (b)Department of Periodontics/Prevention/Geriatrics, School of Dentistry, University of Michigan, Ann Arbor, MI, (c)Department of Endodontics, School of Dentistry, University of Washington, Seattle, WA, (d)Division of Biostatistics, Department of Preventive Medicine, School of Medicine, Vanderbilt University, Nashville, TN,and (e)Department of Periodontology, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT, USA

Purpose: The purpose of this cross-sectional retrospective study was to determine the association between a defined set of clinical factors and treatment outcomes following regenerative therapy in a university-based specialty training program in Periodontics.
Materials and Methods: Data were collected from 131 sites in 82 patients who received various forms of regenerative therapy including barrier and/or bone grafting procedures. Clinical endpoints used in the analyses were reductions in probing pocket depth (PD) and radiographically detectable bone loss (RBL). Multivariate and univariate statistical analyses were used to determine the association between six patient-related factors and four outcome variables. The factors studied were: (1) age, (2) gender, (3) smoking, (4) use of bone allografts, barrier, or combined therapies, (5) position of margins of adjacent restorations, and (6) endodontic status of treated teeth. The four outcome variables were reduction in: (1) buccal PD, (2) lingual PD, (3) average PD, and (4) RBL.
Results: Results indicated an overall improvement in clinical health following therapy. A statistically significant reduction (p<0.01) was found for buccal PD (-1.53 ± 0.22 mm), lingual PD (-1.28 ± 0.22 mm) and average PD (-1.41 ± 0.20) while a 0.72 ± 0.23 mm reduction in RBL (p<0.01) was also noted. Multivariate analysis indicated that only two factors, increased age and smoking, had statistically significant negative effects on treatment outcomes. Univariate analysis indicated a statistically significant negative influence for 1) increasing patient age on buccal PD, lingual PD, and RBL reduction and 2) smoking on RBL reduction. Comparable clinical outcomes were found whether absorbable or non-absorbable barrier materials were used.
Conclusion: In summary, the findings suggest that increased age and smoking appear to be factors associated with poor or sub-optimal regenerative outcomes.
(Int Chin J Dent 2002; 2: 48-59.)