The Influence of the Crown-implant Ratio on the Crestal Bone Level and Implant Secondary Stability

The Influence of the Crown-implant Ratio on the Crestal Bone Level and Implant Secondary Stability - 36 Months Clinical Study

The aim of the study was to determine whether implant length and the crown-to-implant (C/I) ratio influence implant stability and the loss of the surrounding marginal bone, and whether short implants can be used instead of sinus augmentation procedures.

The patients participating in the study (n=30) had one single tooth implant - a short (OsseoSpeed™ L6Ø4 mm, Implants) or a regular implant (OsseoSpeed™ L11 and L13Ø4 mm, DENTSPLY Implants) - placed in the maxilla. The evaluation was based on clinical and radiological examination. The crown-to-implant ratio was determined by dividing the length of the crown together with the abutment by the length of the implant placed crestally. Mean crown-to-implant ratios were calculated separately for each group and its correlation with the MBL (marginal bone loss) and stability was assessed. The authors compared the correlation between the C/I ratio values, MBL and secondary implant stability.

Group 2 (G2; n=15 patients) had short implants (OsseoSpeed ™ L6mm Ø4 mm) [DENTSPLY Implants, Waltham, MA, USA] placed without sinus lift and augmentation procedure.

Group 1 (G1; n=15 patients) had conventional dental implants (OsseoSpeed ™ L11 Ø4 mm and L13 Ø4 mm) [DENTSPLY Implants, Waltham, MA, USA] placed, preceded by the sinus lift procedure from a lateral window approach with the application of the xenogeneic bone graft Geistlich Bio-Oss® [Geistlich AG, Wolhusen, Switzerland]. The lateral window approach sinus lift surgery was performed 6 weeks prior to the implant placement by the same surgeon.

Short implants are placed in the alveolar bone and a clinical Ostell and Periotest evaluation of the implants after a period of time is done. Analysis of periapical radiographs and CBCT images after a period of time. Bone around the implant was measured, marginal bone level loss is determined.

Sinus lift procedure is done and regular implants are placed in the alveolar bone and a clinical Ostell and Periotest evaluation of the implants after a period of time is done. Analysis of periapical radiographs and CBCT images after a period of time. Bone around the implant was measured, marginal bone level loss is determined.

Evaluation of implant secondary stability in both groups. Stability measured and evaluated with Periotest(R) device - after 36 months.

Evalation if there is difference in marginal bone level around the implants in both groups. Periapical radiographs and CBCT images taken and the begining and at the end of the observation period will be compared and bone level will be measured. Loss of marginal bone will be calculated.

Inclusion Criteria: Non-smoking patients with no systemic or local diseases were qualified. Additional inclusion criteria were as follows: minimal apicocoronal height of the alveolar ridge of 6 mm in the region of the implant insertion in the pre-surgical qualification minimal width of the alveolar ridge of 6-7 mm in the region of interest HKT (height of the keratinized tissue) higher than 2 mm API ≤ 35 (Approximal Plaque Index) PI ≤ 25. (Plaque Index) Bone Type III or D2 were included in the study No graft procedures in the area of interest, Exclusion Criteria: -

Hadzik J, Krawiec M, Slawecki K, Kunert-Keil C, Dominiak M, Gedrange T. The Influence of the Crown-Implant Ratio on the Crestal Bone Level and Implant Secondary Stability: 36-Month Clinical Study. Biomed Res Int. 2018 May 16;2018:4246874. doi: 10.1155/2018/4246874. eCollection 2018.