Dental Implants
Conditions
Brief summary
The purpose of the study is to compare two different types of dental implants which will be used to support/retain a removable denture in the edentulous mandible. Subjects will have one implant placed in the midline of the mandible after which the patient's existing denture will be modified to fit the implant. The population of this study consists of healthy edentulous individuals 20-75 years of age who have complete dentures in the upper and lower arch.
Detailed description
Titanium dental implants have been frequently used in the rehabilitation of edentulous patients. Implants may provide adequate denture stability, improve oral function and oral health related quality of life. There is evidence that implants supporting fixed and removable prostheses have excellent long term success rates. Factors such as implant surface characteristics, length, diameter and shape (parallel sided or tapered) may play and important role for the outcome of the treatment especially when the immediate loading protocol (loading of the implant the same day it is surgically placed) is utilized. There are reports indicating that dental implants placed according to the immediate loading protocol can be used to support removable prostheses in the mandible. Such protocol would minimize the number of surgical procedures and significantly shorten the overall treatment time. Further, increased oral health related quality of life has been reported from studies on mandibular implant overdentures. Traditionally two implants have been suggested for the support of a mandibular overdenture. However, high patient satisfaction rates and appropriate denture retention have been reported among patients with a single implant placed in the mid-line. It is also important to further evaluate and compare various implant designs to determine clinical outcomes. The two dominating types of implant body design on the market are the parallel-sided (straight) and the tapered (conical) shaped. Both implants have similar threads, and the surgical procedure for placing the implants in the bone tissue is similar, but the drills used have a slightly different design and shape. There are today no randomized controlled studies evaluating differences in outcomes with respect to the external implant design i.e. parallel sided or tapered.
Interventions
DEVICENobel Biocare titanium dental implants
Sponsors
University of Washington
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
20 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* Be between 20 and 75 years of age * Be edentulous and have both upper and lower complete dentures * Present with American Society of Anesthesiologists (ASA) I or ASA II and no medical contraindications to implant treatment * Have adequate bone volume for placement of one (1) 4.0 mm diameter titanium dental implant with a minimum length of 10 mm in the symphyseal area (=midline) of the anterior mandible * Show absence of pathology such as cysts, infections in the gum tissue or bone and remaining roots. * Be able to understand the procedures and have a jaw opening range of 30 mm or more
Exclusion criteria
* Ongoing chemotherapy * Previous radiation to head/neck * Ongoing corticosteroid medication * Ongoing blood thinner medication * Ongoing medication with psychopharmacological drugs * History of alcohol/drug abuse * Remaining teeth/root tips * Poor quality /fractured/severely worn dentures that cannot be modified to fit the implant * Jaw opening range less than 30 mm
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Difference in Implant Failure Rate Between Parallel Sided and Tapered Dental Implants at 5 Years | From implant placement (baseline) to 5 years | Implant failure defined as an implant that has lost osseointegration and no longer is stable and supported by the surrounding bone (no bone to implant contact). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Implant Stability Quotient (ISQ) Measured at 5 Years | 5 years | The implant stability quotient (ISQ) value is a measurement of the mechanical implant stability in the bone and is measured directly after surgical implant placement and then at follow-ups. It is obtained by resonance frequency with a device that sends out a signal to a metal rod placed in the implant and then reads the value of the signal when it bounces back. The value ranges from 0 to 100 with higher values indicating better bone-to-implant contact and greater stability. |
| Bone Loss Measurement at 5 Years | From implant placement (baseline) to 5 years | The measure of bone loss in millimeters (mm) around the implant at 5 years compared to bone height at baseline. Changes in bone level are measured on intraoral radiographs and compared with the bone level measure immediately after surgical implant placement (baseline). The implant platform was used as the reference point and measurements of the bone were made to the nearest thread. The bone level is measured on both sides (mesial & distal) of the implant using the thread on the implant as reference. The distance between the threads is 0.6 mm. |
Countries
United States
Participant flow
Recruitment details
Participants were recruited via flyers posted in the School of Dentistry. A total of 63 people were screened for eligibility and 48 met the inclusion criteria.
Pre-assignment details
Of 48 eligible participants who signed the consent form and were enrolled in the study, one declined study participation due to lack of willingness to pay for the required cone beam computed tomography (CBCT) pre-surgical procedure. Participants were randomized to implant group the day of surgery.
Participants by arm
| Arm | Count |
|---|---|
| Parallel Sided Implant Group A Parallel sided titanium dental implant will be placed in the edentulous mandible.
Nobel Biocare titanium dental implants | 24 |
| Tapered Shaped Implant Group A tapered shaped titanium dental implant will be placed in the edentulous mandible.
Nobel Biocare titanium dental implants | 23 |
| Total | 47 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Deceased | 1 | 1 |
| Overall Study | Failed implant | 1 | 2 |
| Overall Study | Lost to Follow-up | 7 | 7 |
| Overall Study | Withdrawal by Subject | 2 | 0 |
Baseline characteristics
| Characteristic | Parallel Sided Implant Group | Tapered Shaped Implant Group | Total |
|---|---|---|---|
| Age, Continuous | 61.17 years | 61.74 years | 61.45 years |
| Implant stability quotient (ISQ) | 82.75 units on a scale STANDARD_DEVIATION 2.75 | 81.30 units on a scale STANDARD_DEVIATION 3.65 | 82.04 units on a scale STANDARD_DEVIATION 3.27 |
| Race and Ethnicity Not Collected | — | — | 0 Participants |
| Region of Enrollment United States | 24 Participants | 23 Participants | 47 Participants |
| Sex: Female, Male Female | 15 Participants | 11 Participants | 26 Participants |
| Sex: Female, Male Male | 9 Participants | 12 Participants | 21 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 1 / 24 | 1 / 23 |
| other Total, other adverse events | 2 / 24 | 2 / 23 |
| serious Total, serious adverse events | 0 / 24 | 0 / 23 |
Outcome results
Primary
Difference in Implant Failure Rate Between Parallel Sided and Tapered Dental Implants at 5 Years
Implant failure defined as an implant that has lost osseointegration and no longer is stable and supported by the surrounding bone (no bone to implant contact).
Time frame: From implant placement (baseline) to 5 years
Population: All participants who had an implant placed at the midline of the mandibular arch and their mandibular denture fitted for immediate wearing.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Parallel Sided Implant Group | Difference in Implant Failure Rate Between Parallel Sided and Tapered Dental Implants at 5 Years | 1 Participants |
| Tapered Shaped Implant Group | Difference in Implant Failure Rate Between Parallel Sided and Tapered Dental Implants at 5 Years | 2 Participants |
p-value: 0.63Fisher Exact
Secondary
Bone Loss Measurement at 5 Years
The measure of bone loss in millimeters (mm) around the implant at 5 years compared to bone height at baseline. Changes in bone level are measured on intraoral radiographs and compared with the bone level measure immediately after surgical implant placement (baseline). The implant platform was used as the reference point and measurements of the bone were made to the nearest thread. The bone level is measured on both sides (mesial & distal) of the implant using the thread on the implant as reference. The distance between the threads is 0.6 mm.
Time frame: From implant placement (baseline) to 5 years
Population: Participants continuing in the study at 5 years
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Parallel Sided Implant Group | Bone Loss Measurement at 5 Years | 1.02 millimeters | Standard Deviation 1.37 |
| Tapered Shaped Implant Group | Bone Loss Measurement at 5 Years | 0.65 millimeters | Standard Deviation 1.08 |
p-value: 0.45Unequal-variance 2-sample t-test
Secondary
Implant Stability Quotient (ISQ) Measured at 5 Years
The implant stability quotient (ISQ) value is a measurement of the mechanical implant stability in the bone and is measured directly after surgical implant placement and then at follow-ups. It is obtained by resonance frequency with a device that sends out a signal to a metal rod placed in the implant and then reads the value of the signal when it bounces back. The value ranges from 0 to 100 with higher values indicating better bone-to-implant contact and greater stability.
Time frame: 5 years
Population: Participants continuing in the study at 5 years
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Parallel Sided Implant Group | Implant Stability Quotient (ISQ) Measured at 5 Years | 80.77 units on a scale | Standard Deviation 5.82 |
| Tapered Shaped Implant Group | Implant Stability Quotient (ISQ) Measured at 5 Years | 85.54 units on a scale | Standard Deviation 6.5 |
p-value: 0.06Unequal-variance 2-sample t-test