Long-term follow-up studies published in peer-reviewed journals do not support the experiences and statements by Dr De Angelis. Robertsson and Mohlin reevaluated 53 quadrants with space closure and 36 with space opening after a mean time of 7.1 years. There were statistically significantly fewer locations with plaque and bleeding on probing in the space-closure group. No statistically significant differences for gingival retraction were found between the 2 groups. They concluded that orthodontic space closure produces results that are favored by patients and are healthier compared with prosthetic replacement.
Nordquist and McNeill reported the same findings in 1975. Thordarson et al reported favorable clinical results with excellent oral health 10 to 17 years after treatment in 26 adolescent patients in whom 37 canines were ground to the shape of lateral incisors.
Implants were not included in these studies. Osseointegrated single-tooth implants were developed in the 1980s by Brånemark in Sweden. Consequently, Scandinavian dentists have longer experience with single implants than others. As mentioned in our Point feature, these experiences indicate that, although successful from the standpoint of osseointegration, the esthetic result of implant-supported crowns with time was sometimes less than desired.
Gingival discoloration, infraocclusion of the implant crown, progressive loss of cortical bone, interdental bone loss on natural teeth near the implant, and peri-implantitis can impair the result of implant-supported crowns. Chang et al compared the periodontal conditions around single-tooth implants and contralateral natural teeth in the same patients and found more mucositis and bleeding on probing and greater probing depths on implants than on natural teeth.
We recommend adequate lingual root torque to provide enough thickness of the labial periodontal support and to reduce the risk for bone dehiscence. Since facial height slowly increases in adulthood in investigated groups, the risk for fenestration or loss of the labial bone seems greater for implant-supported crowns than for natural teeth. Fenestrations are generally harmless when natural teeth are present but contribute to unesthetic color changes observed at the labial gingiva of implant crowns. A recent report demonstrated distinct dark gingival discoloration in 8% of 179 implant-supported replacements at the 4-year follow-up.
We maintain that, from a long-term esthetic and periodontal perspective, a tooth is generally preferable to an implant.