Regeneration of Human Intrabony Defects With Recombinant Human Fibroblast Growth Factor 2 in a Hyaluronic Acid Gel Carrier - a Longitudinal, Prospective, Randomized Controlled Clinical Trial

Study Population and Experimental Design The study was designed as a randomized, prospective, split-mouth, controlled clinical trial. It was conducted in accordance with the guidelines of the World Medical Association Declaration of Helsinki (version VI, 2002), after approval of the study design and consent by the Faculty of Medicine, Ethical Committee of Medical Research, Federal Fluminense University (Approval protocol CEP-HUAM/CCM 21/03). Written informed consent was obtained from all subjects. Systemically healthy patients with moderate to advanced chronic periodontitis referred to the Department of Periodontology, Faculty of Dentistry, Federal Fluminense University for periodontal treatment of advanced periodontitis were recruited for and treated in the study.

Inclusion criteria of the study were: (a) adult subjects with chronic periodontitis presenting (b) radiographic evidence alveolar bone loss at the proximal aspect of the tooth, (c) intrabony defect deeper than 4mm, (d) probing pocket depth >6 mm at the site, (e) unremarkable general health according to medical history and clinical judgment, (f) no medications taken for at least six months and no antibiotics taken for twelve months before the beginning of the study. Subjects who have quit the habit of smoking for at least one year before the beginning of the study were considered as non-smokers and, if the other included criteria were met, were included in the present sample. Exclusion criteria for the study were: (a) subjects with "early onset" or aggressive forms of periodontitis, (b) current smokers, (c) presence of significant systemic diseases (i.e., cancer, AIDS, diabetes), (d) clinical evidence of furcation defects, (e) presence of apical radioleucency and (f) previous lack of cooperation with the maintenance program.

Two defects were selected from each patient, and were randomly assigned, immediately before each surgical appointment, by computer generated random sequence allocation to one of the two treatment modalities employed: (a) Control: open instrumentation of the root surfaces and bone defects via flap modified papilla preservation flap; (b) Test: open instrumentation of the root surfaces and bone defects via flap modified papilla preservation flap and application of a rhFGF-2/HA in the intrabony defect. Treatment allocation was registered in an allocation table sheet that was unavailable to the clinical examiner throughout the study. Both the control and test sites were treated at the same surgical appointment and no information on treatment allocation was provided to the patient. All surgical procedures were performed by a single operator, which became aware of the site allocation only after completed root planning and conditioning, and immediately before the application of the growth factor in the test sites. A strict surgical protocol emphasizing careful hard- and soft-tissue management, root debridement, wound stability and infection control was employed (Santana et al 2009; Miranda et al 2013). Nonsurgical infection control was performed in the context of cause- related periodontal therapy and consisted of oral hygiene instructions, scaling and root planing, tooth polishing and plaque control measures performed six months prior to regenerative surgery. Patients were re-evaluated three and six months after the completion of the non-surgical cause-related periodontal therapy and enrolled following the later evaluation appointment.

Clinical Recordings Clinical parameters were assessed using the cemento-enamel junction (CEJ) or, when applicable, another defined landmark, as a fixed reference point. All measurements were recorded using an UNC #15 periodontal probe (PCP-UNC 15, Hu-Friedy, Chicago, IL, USA) by a blinded, trained and calibrated examiner (CMMS), unaware of the treatment provided at baseline and one year after treatment. Measurements were recorded to the nearest mm. Full mouth plaque score (FMPS) was recorded dichotomously as the percentage of total surfaces (four sites per tooth) (O'Leary et al. 1972). BOP was also assessed dichotomously at the same sites, and a full mouth bleeding score was calculated. Recession (REC) was measured as the distance from the CEJ to the gingival margin (GM). Probing depth (PD) was measured as the distance from the GM to the bottom of the gingival sulcus. PD and REC were used to calculate the vertical clinical attachment level (PAL). Under local anesthesia, transgingival probing was performed and the distance between the CEJ and the bottom of the defect (distance CEJ-BD) was also recorded. Clinical measurements obtained at baseline (immediately before surgery) and at twelve months are reported. After debridement of the surgical site, the bottom of the defect (BD) was defined as the distance between cemento-enamel junction and base of the defect. Bone crest level (BC) was measured as the distance between the cementoenamel junction and crest of the defect and the intra-bony defect depth (INTRA) was measured as the subtraction of BC from BD measurements (BD-BC). Moreover, the depth of the three, two and one-wall sub-components of the bony defect were also measured. The primary and secondary outcome variables of the present study were, respectively, change in PAL and bone gain (change in distance CEJ-BD).

In order to ensure the reproducibility and consistency of pre- and post-intervention measurements, examiner calibration was performed before the beginning of the study. Fourteen sites, in seven patients, with probing depths >6 mm were evaluated by the examiner on two separate occasions, 48h apart.