Short Implants in Unitary Implant-supported Rehabilitations in the Posterior Maxilla and Mandible: 5 Years of Follow-up

Short Implants (7 and 8 mm) in Unitary Implant-supported Rehabilitations in the Posterior Sector of the Maxilla and Mandible: 5 Years of Follow-up

Implant-supported rehabilitation of regions with severe bone resorption is a challenge for implant dentists. Structures such as the maxillary sinus and the inferior alveolar canal often make it impossible to use implants of lengths considered standard in the literature. The use of short 7 and 8 mm implants with new macrogeometries and surface treatments, in addition to the application of Morse taper prosthetic connections, has shown results that increasingly encourage their use. However, the longevity of these rehabilitations needs to be constantly evaluated. In this work, unitary implant-supported rehabilitations in the posterior jaws, supported by short (7 and 8 mm) tapered Morse connection implants, will be followed for a period of 5 years. A total of 100 subjects rehabilitated with tapered Morse connection implants, with diameters between 3.5 and 4.5 mm, will be evaluated. Peri-implant bone remodeling, implant stability measured through ISQ and clinical parameters will be evaluated per implant and over the evaluation time. Periapical radiographs will be obtained and digitized, analyzed by software and compared with the initial data. The data obtained will be analyzed, allowing longitudinal evaluations and the success rate of implant restorations supported by short implants.

3.3. Clinical examinations A single, trained and calibrated examiner will perform all clinical examinations. The examiner will be trained and calibrated before and during the study in order to achieve maximum reproducibility in measurements. The methodology to be used for intra-examiner calibration will be the one recommended by Araujo et al. 2003, in which the standard error of measurement for continuous periodontal clinical parameters (SP and CIN) is evaluated. For the other clinical variables, the mean level of agreement between the examiners will be determined and considered satisfactory when the value is greater than 90% (Kappa test).

Clinical measures

The following parameters will be recorded at six sites per implant using a periodontal probe North Carolina (Hu-Friedy, Chicago, IL, USA):

1. Plate index (PI): 0 = absence of plaque; 1 = separate patches of plaque at the cervical margin; 2 = a thin, continuous band of plaque [up to 1 mm] at the cervical margin of the tooth; 3 = strip of plaque greater than 1 mm, but covering less than 1/3 of the tooth crown; 4 = plaque that covers at least 1/3 but less than 2/3 of the tooth's crown; 5 = plate covering 2/3 or more of the tooth's crown).
2. Gingival index (GI): 0 = absence of inflammation; 1 = mild inflammation change in color and little change in texture; 2 = moderate inflammation - tempered glasses, redness, edema and hypertrophy; 3 = severe inflammation - marked redness and hyperplasia.
3. Bleeding on probing (SS): 0 = absence; 1 = presence.
4. Suppuration (Sup): 0 = absence; 1 = presence.
5. Probing depth (PS): distance (mm) from the peri-implant mucosal margin to the most apical portion of the peri-implant pocket.
6. Relative attachment level (NI): distance (mm) from the implant shoulder to the most apical portion of the peri-implant pocket.
7. Keratinized tissue height (THA): vertical distance (mm) measured from the mucogingival line to the peri-implant margin in the center of the buccal face of the implant.
8. Keratinized tissue thickness 1 (ETQ1): measured in the center of the buccal surface of the ridge, at the midpoint between the mucogingival line and the top of the ridge.
9. Mesial and distal keratinized tissue thickness 2 (ETQ2M, ETQ2D): measured over the ridge (mesial and distal of the implant) when the crown can be removed.
10. Evaluation of the biotype of peri-implant tissue (Rouk et al. 2009): thin or thick, according to the visualization of the periodontal probe through the peri-implant tissue.

Screw-retained implant crowns will be removed to observe clinical records, while cemented crowns will not be removed.

Radiographic measurements As a way of evaluating the stability of bone tissue, the interproximal level of the bone crest will be measured by means of periapical radiographs. After the radiographic takes, the radiographs will be scanned and the distance in millimeters from the interproximal bone crest to the base of the implant will be evaluated.

ISQ Stability Type 16 smartpegs will be inserted directly into the implants for ISQ evaluation Implant Stability Quotient) by means of an appropriate device (Osstell, Integration Diagnostics, Savadal, Sweden). For each series of measurements, the resonance analysis frequency unit (RFA - Resonance Frequency Analysis) will be used, observing that the ISQ varies between 1 and 100, and the measurements will be made 3 consecutive times to obtain the average.

3.4. Analysis Model

The primary outcome variable of the study will be variation in bone remodeling between the initial and final values. The radiographic parameter will be calculated for each face (mesial and distal) and then the average among the volunteers in each evaluation period will be calculated separately. The Wilcoxon Rank non-parametric paired test will be used to compare differences between baseline values and each assessment period. The significance level will be 5%.

Inclusion Criteria:

• Individuals (> 21 years old), of both sexes, specifically rehabilitated with morse connection implants (Implacil De Bortoli, São Paulo, SP, Brazil) in the posterior region of the jaws for single-sided unsupported restorations, will be included in this study. Individuals will also need to have at least initial radiographic controls (immediately after implant placement) and 12 and 60 months of follow-up after implant placement. Individuals will be included in the population sample, with the following criteria observed: location, implant installation region, implant diameter, and adaptation.

Exclusion Criteria:

• Immediate implants will be excluded, individuals with clinical records who, throughout the study, do not have radiographs for evaluation and/or radiographs of poor quality that make radiographic measurements impossible; medical records with insufficient data, filled out inappropriately or that indicate doubt about the details of the procedure performed.