Study Population and Experimental Design

Patients with advanced periodontal disease, in general good health, and presenting with deep intrabony defects were considered eligible for this study. The study protocol was approved by the local ethics committee and all subjects gave informed consent. Patients were enrolled in the authors’ private practices from January to July 2002 and were included after completion of initial, cause-related therapy consisting of scaling and root planing, motivation, and oral hygiene instructions. Flap surgery was completed as needed in the remaining portions of the dentition before proceeding with regenerative treatment and thus inclusion into the study. Inclusion criteria were (Fig. 1): 

1. Absence of relevant medical conditions.
   Patients with uncontrolled or poorly controlled diabetes, unstable or life-threatening conditions, or requiring antibiotic prophylaxis were excluded.
2. Smoking status.
   Only non-smokers were included.
3. Defect anatomy.
   Presence of one tooth with probing depth (PD) and clinical attachment level (CAL) loss ≥6 mm associated with an intrabony defect ≥4 mm.
4. Good oral hygiene.
   Full-mouth plaque score (FMPS) ≤15%.
5. Low levels of residual infection.
   Full-mouth bleeding score (FMBS) ≤15%.
6. Compliance.
   Only patients with optimal compliance were selected as demonstrated during the initial cause-related phase of therapy.
7. Endodontic status.
   Teeth had to be vital or properly treated with root canal therapy. 

Forty deep intrabony defects in 40 subjects (mean age 41.3 ± 10.7, range 23 to 65 years, 23 females), which met the admission criteria were included in this case cohort.

Three months after completion of periodontal therapy, baseline clinical measurements were recorded. The regenerative strategy was selected according to a decision making process (Fig. 2). Surgical procedures, based on the principles of periodontal regeneration, were performed. Defects were measured during surgery.

Patients were enrolled in a stringent periodontal supportive care program for 1 year. At 1 year, clinical measurements were recorded. Surgery and measurements were performed independently by the two authors.

Clinical Measures at Baseline and at 1 Year

The following clinical parameters were evaluated at baseline and 1 year after regenerative therapy. Full-mouth plaque scores (FMPS) were recorded as the percentage of total surfaces (four aspects per tooth) which revealed the presence of plaque. Bleeding on probing (BOP) was assessed dichotomously at a force of 0.3 N with a manual pressure-sensitive probe; full-mouth bleeding scores (FMBS) were then calculated. Probing depth (PD) and recession of the gingival margin (REC) were recorded to the nearest millimeter at the deepest location of the selected interproximal site. All measurements and BOP were taken with a pressure sensitive manual periodontal probe ^‡ at 0.3 N. Clinical attachment levels (CAL) were calculated as the sum of PD and REC. Radiographic defect angle was measured on a periapical radiograph, as previously described.

Selecting the Regenerative Strategy

The intrabony defects were treated with periodontal regeneration. The appropriate regenerative strategy in the different cases was selected according to a previously described, evidence-based operative decision tree as recently modified (Fig. 2).

One of three surgical access approaches was used: the simplified papilla preservation flap (SPPF) was performed whenever the width of the interdental space was ≤2 mm as measured at the level of the papilla; the modified papilla preservation technique (MPPT) was used at sites with an interdental width >2 mm; and the crestal incision was used next to an edentulous area.

Selection of the regenerative strategy was based on the defect anatomy (Fig. 2). An ePTFE titanium reinforced membrane § was used when the defect anatomy was not “supportive,” such as in wide and 1- or 2-wall defects (Fig. 3). As an alternative, a bioabsorbable membrane ^|| supported with a filler material (Fig. 4) was used in instances when the non-supportive defects were associated with narrow interdental spaces. A bioabsorbable membrane § was applied alone in “supportive” defects (Fig. 5), such as narrow and 2- or 3-wall defects. EMD ^¶ was preferred in defects with a prevalent 3-wall morphology (Fig. 6).

The suturing approach was based on the defect anatomy and regenerative surgery (Fig. 2). It consisted of a combination of two sutures applied in the defect-associated interdental area to reach primary closure of the papilla in the absence of any tension.

The first interdental suture was positioned between the apical part of the buccal gingiva, near the mucogingival junction, and an apical area of the lingual/palatal flap. In supportive defects (3-wall defects) or in the presence of a supportive membrane (titanium ePTFE membrane), or a supported membrane (bioabsorbable and filler), an internal horizontal crossed mattress suture was used. In non-supportive defects and in the presence of bioabsorbable membranes or EMD, an offset internal mattress suture was preferred. When a crestal incision was performed, internal horizontal mattress sutures were applied. The aims were to relieve the residual tension of the flaps in the defect-associated area and to coronally displace the buccal flap.

A second, more coronal internal mattress suture was placed to passively close the interdental papilla over the regenerative material.

The surgical procedures were performed with the aid of an operating microscope ^# at a magnification of 4× to 16×. Microsurgical instruments were utilized, when needed, as a complement to the normal periodontal set of instruments. Incisions were carried out using delaminating microsurgical blades;** 5-0 ePTFE sutures were used to relieve the tension of the flaps, while 6-0 or 7-0 ePTFE sutures were preferred to obtain primary closure of the interdental tissues. Primary closure of the flaps over the membranes was recorded at completion of surgery and at weekly recalls for 6 weeks.

A protocol for the control of bacterial contamination consisting of doxycycline (100 mg b.i.d. for 1 week), 0.12% chlorhexidine mouth rinsing three times per day, and weekly prophylaxis was prescribed. 35 Patients were instructed to avoid brushing, flossing, and chewing in the treated area for periods of 6 to 10 weeks. Non-resorbable membranes were removed after 6 weeks. Patients resumed full oral hygiene and chewing function 2 to 4 weeks after membrane removal or when bioabsorbable membranes were fully resorbed. Patients treated with EMD resumed full oral hygiene after a period of 4 to 5 weeks. At the end of the early healing phase, patients were placed on monthly recall for 1 year.

Clinical Characterization of Selected Sites

Defect morphology was characterized intra-surgically in terms of distance between the cemento-enamel junction and the bottom of the defect (CEJ-BD) and total depth of the intrabony component of the defect (INFRA), essentially as previously described. The depth of the 3-, 2-, and 1-wall subcomponents were also recorded.

Data Analysis

Data were expressed as means ± standard deviation of 40 defects in 40 patients. No data points were missing. Comparisons between baseline and 1 year data were made using the Student t test (alpha = 0.05). CAL gains, residual PD, and position of the gingival margin were the primary outcome variables. Percentage fill of the baseline intrabony component of the defect was calculated as: CAL% = (CAL gains)/INFRA * 100.