Resonance frequency measurement of implant stability in vivo on implants with a sandblasted and acid-etched surface.
OBJECTIVE
To determine the changes in stability as a reflection of early healing around single-stage, roughened-surface implants in humans utilizing resonance frequency analysis (RFA). RFA makes use of a transducer, attached to an implant, which is excited over a range of sound frequencies with subsequent response analysis.


METHODS
Twenty patients had 1 to 4 implants placed in the posterior maxilla or mandible. Bone type was classified into 1 of 4 groups according to the Lekholm and Zarb index (1985). RFA was used for direct measurement of implant stability on the day of implant placement and consecutively once per week for 6 weeks and at weeks 8 and 10.


RESULTS
Twenty-seven ITI SLA implants placed in the premolar and molar regions of the maxilla and mandible were evaluated. Early failure occurred with 1 implant related to parafunction. The remaining 26 implants were distributed as follows: 29.6% in Type 1 bone, 37% in Type 2 or 3 bone, and 33.3% in Type 4 bone. The lowest mean stability measurement was at 3 weeks for all bone types. The percentage decrease in stability from baseline to 3 weeks was highest for Type 4 bone (8.6%), as was the percentage increase in stability from 3 to 10 weeks (26.9%). A Bonferroni adjusted Student t test comparison of bone groups at each time point revealed highly significant differences between implant stability in Types 1 and 4 bone at 3 weeks (P = .004) and a moderately significant difference between Types 2, 3, and 4 bone (P = .08) at 3 weeks. Implant stability did not change significantly during the 10-week period in Type 1 bone (P > .10). With the same test, by 5 weeks, no bone groups showed any difference in implant RFA measurements (P = 1.0).


CONCLUSIONS
This study demonstrated the lowest values for implant stability at 3 weeks after placement for all bone types. This effect was statistically significant and most pronounced in Type 4 bone.


CONCLUSIONS
There was no significant difference in the pattern of stability changes among different bone types after 5 weeks of healing.
Barewal
Reva M
RM
Department of Prosthodontics, Oregon Health Sciences University, Portland, Oregon, USA.
Oates
Thomas W
TW
Meredith
Neil
N
Cochran
David L
DL
D000134:Acid Etching, Dental; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015519:Bone Density / Q000502:physiology; D045662:Dental Etching / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology*; D011446:Prospective Studies; D013016:Sound; D013499:Surface Properties; D014159:Transducers; D014945:Wound Healing / Q000502:physiology
D015921:Dental Implants