Regenerative periodontal therapy of infra-bony defects using minimally-invasive surgery and a collagen-enriched bovine-derived xenograft : a 1-year prospective study on clinical and aesthetic outcome

Purpose: To evaluate the clinical and aesthetic outcome of regenerative periodontal therapy (RPT) using minimally-invasive surgery and a collagen-enriched bovine-derived xenograft (1); to identify risk factors for failure (clinical attachment level (CAL) gain ≤ 1 mm) and advanced gingival recession (REC) increase (> 1 mm) (2). Material and methods: Ninety-five non-smoking patients with ≤ 25 % full-mouth plaque and bleeding presenting ≥ 6 months after initial periodontal therapy with ≥ 1 isolated interdental infra-bony defect were recruited. Patients were consecutively treated by the same clinician using minimally invasive surgery and a collagen-enriched bovine-derived xenograft. Clinical, radiographic and aesthetic data were collected before surgery and up to one year. Multivariate analyses were used to identify risk factors for failure and advanced REC increase. Results: Eighty-four patients (39 men, 45 women; mean age 53) complied and demonstrated mean probing depth (PD) of 7.8 mm, CAL of 10.0 mm and defect depth of 5.2 mm before surgery. At one year post surgery mean PD reduction was 3.5 mm (range 0.0 – 8.0), CAL gain was 3.1 mm (range 0.0 – 7.0) and radiographic defect fill was 53 % (range 0 – 100). Fourty-nine % showed ≥ 4 mm CAL gain whereas 15 % were considered failures. Mean interdental and midfacial REC increase was 0.3 mm (range -2.0 – 2.0) and 0.5 mm (range -1.5 – 2.0), respectively. Midfacial REC increase and contour deterioration contributed most to a small, yet significant reduction in the Pink Esthetic Score from 10.06 to 9.42 (p = 0.002). Risk factors for failure included defects with a non-supportive anatomy (OR ≥ 10.4), plaque (OR: 14.7) and complication(s) (OR: 12.0). Risk factors for advanced midfacial REC increase included defects with a non-supportive anatomy (OR: 58.8) and a thin-scalloped gingival biotype (OR: 76.9). Conclusions: RPT using minimally-invasive surgery and a collagen-enriched bovine-derived xenograft demonstrated favourable clinical outcome after one year even though soft tissue aesthetics could not be fully preserved. Defects with a non-supporting anatomy may be at risk for failure and advanced midfacial recession