Influence of Insertion Torque and Bone Type on Post-operative Pain

This prospective clinical study included 230 patients treated with a single tapered screw implant (Bioinnovation Dental®, Brazil). The implants were placed using the appropriate burs with a final master drill of 3.5 or 4.5 mm in diameter by one senior oral surgeon. These implants were multi-threaded, and their surfaces were both sandblasted and acid etched. Of the 230 participants, 172 received a single 5 x 10-mm implant, and 58 received a 4 x 10-mm implant.

For the higher torque range (90 - 200 Ncm), the maximum IT was recorded with an electronic digital torque measuring device (Tohnichi BTGE200CN-G, Hitachi, Japan), while a different gauge (Tohnichi BTG90CN-S, Hitachi, Japan) was used for the lower torque range (10 - 90 Ncm). All implants were placed at the crestal level and closed with a cover screw, and the flap was then sutured with non-resorbable 4/0 nylon suture (Resorba® Germany).

Pain levels were recorded at day 1, 2 and 4 and at week 1, 2 and 3 after surgery using visual analog scale (VAS) ranging from 0 "no pain" to 10 "worst pain ever. Implants were classified into 4 groups based on the IT value; Low: 60 implants (10-29 Ncm, mean=15 Ncm); Regular: 102 implants (30-50 Ncm, mean=42 Ncm); High: 47 implants (51-100 Ncm, mean=75 Ncm); and Very high: 21 implants (101-200 Ncm, mean=170 Ncm).

Implant survival was assessed clinically and radiographically at 3, 6, 12, 24 and 36 months. The criteria for implant success according to Buser et al, were no radiolucent zone around the implant, confirmed individual implant stability, and no suppuration, pain or ongoing pathologic processes. All implants that failed to fulfill these success criteria were regarded as failures.

The effect of IT, bone type, implant location, age, gender and smoking was measured with regression analysis. Kaplan-Meier survival analysis was performed to calculate the overall implant survival probabilities. The level of statistical significance was set at p<0.05.

Inclusion criteria

• partially edentulous patients who presented with one or more missing teeth in the maxillary or mandibular jaw
• at least18 years old, adequate oral hygiene
• absence of infection or periodontal problems adjacent to the implant site - sufficient bone thickness with a minimum 6-mm width and 12-mm length to accommodate implants of 4 or 5 mm in diameter and 10 mm in length.

Exclusion criteria

• uncontrolled diabetes
• hypertension
• pregnancy
• bone diseases
• use of bisphosphonates
• heavy smoker (more than 20 cigarettes /day)
• severe alcohol or drug use
• patients with recent extraction of teeth and patients requiring bone and soft tissue augmentation procedures.