Purpose: To evaluate radiographic and clinical outcomes of immediate occlusally loaded one-piece zirconia implants after five years of follow-up. Materials and methods: This longitudinal clinical investigation included patients older than 18 years, in need of implant-supported single-unit dental rehabilitation, with good systemic health and with no general contraindications against implant treatment. One-piece zirconia implants were placed in healed and post-extraction sites. Provisional restorations in light occlusal contact were provided immediately after implant insertion. Definitive zirconia-ceramic restorations were delivered 3-4 months after surgery. Primary estimated outcomes were implant survival and success. Periapical radiographs were taken at implant insertion (T0), after 1 year (T1) and after 5 years (T2) to assess marginal bone loss (MBL). Probing depth (PD), modified bleeding index (mBI), modified plaque index (mPI) and gingival recession (REC) were also repeatedly measured for implants and reference teeth. Changes in parameters over time were assessed using the Wilcoxon-Signed-Ranks test. In addition, multilevel mixed effects linear and logistic regression models were fitted to take into account within-subject correlation and baseline values. Results: A total of 32 one-piece zirconia implants were inserted in post-extraction (16 implants) and healed sites (16 implants) in 17 patients. One immediate implant was lost after three months and one patient with one implant dropped out after T1. Therefore, the cumulative survival rate at T1 was 96.9% and at T2 (4.3-6 years) 96.8%. At T1 all survived implants were considered to be of success grade I, while at T2 one implant of those surviving exhibited MBL of 2.4mm (success grade II). At T1 average MBL was 0.83mm (SD, 0.24) and at T2 it was 1.23mm (SD, 0.29). No significant differences were observed in mean MBL between immediate and delayed implants at both T1 (p=0.3449) and T2 (p=0.3888). Moreover, different baseline parameters did not show any influence on MBL at both T1 and T2. Mean value of PD for implants decreased slightly and continuously from 2.55 mm to 2.20 mm (p=0.0027). The mean values of mBI and mPI showed a gradual decrease over time, statistically important for mBI (p=0.0290). REC decreased to some extent at T1 and increased at T2, resulting in statistically significant (p<0.0001) but not clinically-relevant changes (<0.5mm). In mean, for all clinical parameters, implants seemed to perform similarly if not better than natural teeth. Conclusions: Based on the study of 32 one-piece zirconia implants followed for a minimum of 4.3 years the projected five-year survival rate is 96.8%. Moreover, radiographic and clinical evaluations at five years of follow-up show satisfactory levels of MBL and acceptable soft tissue health.
Immediate occlusal loading of one-piece zironia implants: five years radiographic and clinical evaluation.
KALEMAJ, ZAMIRA
2015-01-01
Abstract
Purpose: To evaluate radiographic and clinical outcomes of immediate occlusally loaded one-piece zirconia implants after five years of follow-up. Materials and methods: This longitudinal clinical investigation included patients older than 18 years, in need of implant-supported single-unit dental rehabilitation, with good systemic health and with no general contraindications against implant treatment. One-piece zirconia implants were placed in healed and post-extraction sites. Provisional restorations in light occlusal contact were provided immediately after implant insertion. Definitive zirconia-ceramic restorations were delivered 3-4 months after surgery. Primary estimated outcomes were implant survival and success. Periapical radiographs were taken at implant insertion (T0), after 1 year (T1) and after 5 years (T2) to assess marginal bone loss (MBL). Probing depth (PD), modified bleeding index (mBI), modified plaque index (mPI) and gingival recession (REC) were also repeatedly measured for implants and reference teeth. Changes in parameters over time were assessed using the Wilcoxon-Signed-Ranks test. In addition, multilevel mixed effects linear and logistic regression models were fitted to take into account within-subject correlation and baseline values. Results: A total of 32 one-piece zirconia implants were inserted in post-extraction (16 implants) and healed sites (16 implants) in 17 patients. One immediate implant was lost after three months and one patient with one implant dropped out after T1. Therefore, the cumulative survival rate at T1 was 96.9% and at T2 (4.3-6 years) 96.8%. At T1 all survived implants were considered to be of success grade I, while at T2 one implant of those surviving exhibited MBL of 2.4mm (success grade II). At T1 average MBL was 0.83mm (SD, 0.24) and at T2 it was 1.23mm (SD, 0.29). No significant differences were observed in mean MBL between immediate and delayed implants at both T1 (p=0.3449) and T2 (p=0.3888). Moreover, different baseline parameters did not show any influence on MBL at both T1 and T2. Mean value of PD for implants decreased slightly and continuously from 2.55 mm to 2.20 mm (p=0.0027). The mean values of mBI and mPI showed a gradual decrease over time, statistically important for mBI (p=0.0290). REC decreased to some extent at T1 and increased at T2, resulting in statistically significant (p<0.0001) but not clinically-relevant changes (<0.5mm). In mean, for all clinical parameters, implants seemed to perform similarly if not better than natural teeth. Conclusions: Based on the study of 32 one-piece zirconia implants followed for a minimum of 4.3 years the projected five-year survival rate is 96.8%. Moreover, radiographic and clinical evaluations at five years of follow-up show satisfactory levels of MBL and acceptable soft tissue health.
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