Effect of implant support on distal-extension removable partial dentures: in vivo assessment.
OBJECTIVE
The use of a limited number of implants for support of a removable partial denture (RPD) changes a Kennedy Class I or II situation to that of a Class III. This in vivo pilot study evaluated implant-supported distal-extension removable partial dentures (RPD) in 5 partially edentulous patients.


METHODS
Two implants (Brånemark TU MK III, Nobel Biocare) were placed in a mandibular Kennedy Class I arch. To fabricate an implant-supported RPD (ISRPD), a conventional RPD base was fitted to the healing abutment with autopolymerizing acrylic resin (Uni-fast II, GC) to support the posterior aspect of the RPD. By changing the healing abutment to a healing cap, there was no connection between the denture base and implant, and the ISRPD became a conventional RPD (CRPD). Using a crossover study design, the masticatory movements (mandibular movements during mastication) of both dentures were measured using a commercially available tracking device (BioPACK, Bioresearch, Japan). The occlusal force and contact area were also measured using pressure-sensitive sheets and an image scanner (T-scan system). Using a visual analog scale (VAS), the 4 criteria of comfort, chewing, retention, and stability were evaluated. All the data obtained were analyzed using Wilcoxen signed rank tests (alpha = .05).


RESULTS
There were no significant differences (P > .05) in masticatory movements between the ISRPD and the CRPD (5 patients: 4 women, 1 man). However, the ISRPD had significantly greater force and greater area than the CRPD (P = .043). The center of occlusal force of the ISRPD tended to move more distally compared to the CRPD. All the patients preferred the ISRPD for comfort, chewing, retention, and stability.


CONCLUSIONS
One implant per edentulous area and a simple attachment technique yielded a stable distal extension RPD.
Ohkubo
Chikahiro
C
Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi Tsurumi-ku, Yokohama 230-8501, Japan. okubo-c@tsurumi-u.ac.jp
Kobayashi
Mariko
M
Suzuki
Yasunori
Y
Hosoi
Toshio
T
D000180:Acrylic Resins / Q000737:chemistry; D001732:Bite Force; D018592:Cross-Over Studies; D000044:Dental Abutments; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D003819:Denture Bases; D003779:Denture Design; D003781:Denture Retention; D003832:Denture, Partial, Removable; D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D007576:Jaw, Edentulous, Partially / Q000145:classification / Q000601:surgery; D008297:Male; D008334:Mandible / Q000601:surgery; D008409:Mastication / Q000502:physiology; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D009068:Movement; D017060:Patient Satisfaction; D010865:Pilot Projects; D016037:Single-Blind Method; D013997:Time Factors
D000180:Acrylic Resins; D015921:Dental Implants; D003764:Dental Materials; C112073:unifast II