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ePaper created 2018-02-14, 12:02:22 | version 1.38.0
1 - y e a r s t u d y o f n o n s u b m e r g e d i m p l a n t s Fig. 1 Fig. 1 Optical microscopy and environmental scanning electron microscopy images showing the hyperbolic machined collar and the microtopography of the collar, body and apex portions of Prama implant. H a r d - a n d s o f t - t i s s u e e v a l u a t i o n Marginal bone level (MBL): Intraoral periapical radiographs of all of the implants were taken using the paralleling technique with Rinn hold- ers (Dentsply Rinn, Elgin, Ill., U.S.) and analog films (Kodak Ektaspeed Plus, Eastman Kodak, Rochester, N.Y., U.S.) after implant placement (baseline) and at 1, 3, 6 and 12 months (T1, T3, T6, T12) after implant insertion. All radiographs were scanned with a slide scanner with a resolution of 968 dpi and a mag- nification factor of ×20. The known lengths and diameters of the implants were used to calibrate the measurement. The crestal marginal bone and the bone–implant interface were examined to evaluate the marginal bone morphology. MBL was assessed at the mesial and distal implant surfaces by measuring the distance between the reference point of the implant platform to the most coronal bone–implant contact level using a scale of 0.1 mm increments according to previous studies17, 18 and corrected according to the known length and diameter of each implant.19 Radiographic evaluation was performed single- blinded by 1 additional examiner (F.Z.). Before evaluating the radiographs, the examiner was calibrated using well-defined instructions and reference radiographs with different MBL measures. Periimplant soft-tissue thickness/gingival biotype: The soft-tissue thickness around the implants and their corresponding mesial/distal neighboring teeth was determined. The soft tissue was pierced midfacially at 3 mm apical to the gingival margin with an endodontic file (No. 20 K-file, Dentsply Maillefer, Switzerland). Gingival biotype was defined as thick (soft- tissue thickness > 2 mm) or thin (soft-tissue thickness ≤ 2 mm).20–22 Pink Esthetic Score (PES): PES 23 was assessed preoperatively and at T6 and T12. Seven variables were evaluated against a natural ref- erence tooth by 1 trained operator (the contra- lateral tooth for an incisor and contralateral tooth or neighboring tooth for a premolar) using a 0–2 scoring system (0 being the lowest and 2 being the highest value): mesial papilla, distal papilla, soft-tissue level, soft-tissue contour, alveolar process deficiency, soft-tissue color and soft-tissue texture. The maximum achievable PES was 14. According to Raes et al., a PES < 8 is considered an esthetic failure, while a PES ≥ 12 is considered an (almost) perfect outcome.1 Papilla index (PI): PI24 was assessed mesially and distally by 1 trained operator using a 0–4 scale at T6 and T12. A PI score was given as fol- lows: 0 = no papilla; 1 = papilla fills less than 50% of the interproximal space; 2 = papilla fills more than 50% of the interproximal space, but not entirely; 3 = papilla fills the entire interproximal space harmoniously; 4 = hyperplastic papilla. Plaque score: Plaque score25 was assessed at 4 sites (mesial, distal, vestibular and palatal) around the implant restorations at T6 and T12. A dichotomous score was given (0 = no visible plaque at the soft margin; 1 = visible plaque at the soft margin). Bleeding on probing (BoP): BoP25 was mea- sured at 4 sites (mesial, distal, vestibular and palatal) around the implant restorations at T6 and T12. A dichotomous score was given (0 = no bleeding; 1 = bleeding). S t a t i s t i c a l a n a l y s i s o f t h e M B L Linear regression models were fitted to evaluate the existence of any significant difference regarding placement (immediate, early and delayed), times (1 month, 3 months, 6 months and 12 months), and the interactions between placement and time. In order to take into account the correlation in the data due to the presence of multiple implants per subject, the Journal of Oral Science & Rehabilitation Volume 3 | Issue 4/2017 35