This Study Will be Directed Toward Evaluating Peri-implant Tissue Behavior, Pink Esthetic Score, Patient Satisfaction and Marginal Accuracy Associated With Biologically Oriented Preparation Technique for Implant Supported Crowns.

Armamentarium:

To conduct the present study, the following will be used:

1. Conventional titanium abutments
2. Biologically oriented prepared titanium abutments
3. Dental implants
4. Intra oral scanner software

Methodology:

1. Sample size calculation: a T test was used, according to Mandello etal, study. (31) A sample size (n=20, divided to 10 in each group) will be sufficient to detect a large effect size (d) = 1.4, with an actual power (1-β error) of 0.8 (80%) and a significance level (α error) 0.05 (5%) for two-sided hypothesis test.
2. Subject and selection method: The study will be conducted on 20 patients with missing single tooth indicated for implants, attending the outpatient clinic of the Crowns and Bridges department, Faculty of Dental Medicine for Girls, Al-Azhar University. The study will be conducted after obtaining the approval of the Research Ethics Committee (REC), Faculty of Dental Medicine for Girls, Al-Azhar University, Egypt, under code: The patients will be informed about the purpose of the investigation, the clinical procedures and the advantages/risks of the applied materials 7 and techniques. A written informed consent form will be signed from patients prior to study initiation, appendix (1).
3. Procedure methodology: Diagnostic procedure: Intra oral examination, cone beam computed tomogram (CBCT) will be taken prior to any procedure. All patients (N=20) will be treated with implants.
4. Sample grouping: The patients will be divided into two groups (n=10) according to the type of abutment used: Group (1): will receive conventional shoulder titanium abutment. Group (2): will receive customized titanium biologically oriented prepared abutments or shoulderless abutments that are prepared in the same manner as the natural abutment teeth in the BOPT protocol with 1 or 1.5 mm below the gingival margin in order to simulate the natural emergence profile of the teeth. Construction of the crowns: Patients in both groups will receive porcelain fused to metal crowns.
5. Assessment of:
6. Soft tissue thickness: By using intraoral scanner software; Initial measurements that will be taken at the day of definitive crown insertion are compared with those taken at 3, 6 and one year follow-up appointments. (31) 9
7. Hard tissue thickness: Marginal bone level will be evaluated directly after insertion of implant, directly before loading, 1, 3, and 6 months after loading, peri-implant bone levels tended to stabilize after this time, and no further marginal bone resorption will occur (33). It will be evaluated by means of standardized parallelized periapical radiographs using an X-ray positioner. (13)
8. Marginal discrepancy: It will be evaluated by using the dual scan replica technique.(29) This technique involves making a digital scan of the prepared tooth using the 3D scan settings of the designated software. After the crown fabrication on the prepared tooth model, a light body impression material is used to prepare the impression, which will be then poured on the crown's internal surface after applying a thin layer of separating medium (petroleum jelly). The crown is then seated with an application of finger pressure; after setting of the light body impression material, the crown is detached gently, leaving the light body material coating the prepared tooth surface. Next, this tooth model is scanned again (secondary scan) with the appropriate settings of the designated software. The resultant image is superimposed over the original scan of the prepared tooth. Using the cross-sectional digital tool on the superimposed image, both the original contour of the 10 prepared tooth and the layer of light body material (representing the discrepancy of the internal fit and marginal discrepancy) are visualized and measured utilizing the measurement tool in the software.
9. Pink esthetic score: (34) By using standardized intraoral photographs evaluation of Pink Esthetic Score [PES] will be done by two examiners using certain evaluation criteria.
10. Patient satisfaction: (35) By using a subjective outcome questionnaire filled out by patient him/herself.
11. Statistical analysis Statistical analysis will be performed using a commercially available software program (SPSS Chicago, IL, USA).

Quantitative data will be expressed as mean and standard deviation or median and range according to normality. Independent t test or Mann Whitney U test will be used for comparison.

Categorical data will be described as count and percentages. Data will be compared using chi square test. The level of significance will be set at P≤0.05. All tests will be two tailed.