Presenter: 施佑昇 2012 04 17

Introduction Implant-supported short-span FDPs with cantilever extensions: 5-year survival rate 94.3% Estimated mean biological complication rate  5.4% (Aglietta et al. 2009). The long-term outcomes of implant-supported FDPs with cantilever extensions are comparable with those reported for implant-supported end-abutment FDPs (Pjetursson et al. 2004). In clinical situations where two or more missing teeth need to be replaced, the insertion of two implants is normally recommended to support either two SCs or a FDP. In some cases, however, the lack of adequate bone volume The outcomes of a systematic review on …

Introduction No significant difference in marginal bone level changes after loading of implants supporting FDPs with or without cantilever extensions. (Wennstrom et al. 2004; Halg et al. 2008) The 5-year results of two studies failed to demonstrate a

Aim To evaluate the survival rates and the clinical and radiographic changes at Implant-supported SCs with a cantilever extension FDPs supported by two implants with a cantilever extension After at least 3 years of function.

Material and Methods

Patient selection Retrospective, case–control study Implant support SC at posterior with cantilever 2 Implants support FPDs at posterior with cantilever Tissue level, solid-screw, (SLA surface, a diameter of 4.1 or 4.8 mm, a supracrestal neck height of 1.8 or 2.8 mm (Straumann®) Presence of an opposing dentition >age 18 years; • partially edentulous subjects with healthy or treated periodontal conditions and enrolled in a regular maintenance care program; • absence of relevant medical conditions; • presence of implants in the posterior maxilla and mandible after a transmucosal healing of 3–6 months; • total of 4–6 months of healing between tooth extraction and implant insertion; • availability of a periapical radiograph taken at baseline (i.e. prosthesis delivery) by means of the parallel long-cone technique; • availability of pocket probing depth (PPD) measurements taken at baseline (i.e. prosthesis delivery) at four sites around each implant with a graduated Michigan periodontal probe. Subjects were excluded on the basis of: • uncontrolled medical conditions; • untreated periodontal conditions; • immediate implant placement; • bone regenerative procedures prior to or concomitant to implant placement; • mesial and distal cantilever extensions in the same fixed reconstruction; • SCs or FDPs with a cantilever extension corresponding to more than one dental unit; • SCs or FDPs supported by reduced diameter implants (e.g. 3.3 mm), hollow-screw and hollow-cylinder implants.

Study population

Examination Baseline: Prosthesis delivery Follow-up at least 3Ys Clinical probing depths Radiography

Result

Implant-based mean bone levels Implant survival rate 100%

Site-based mean bone levels

Radiographic marginal bone level change

Mean pocket probing depths

Discussion

Discussion A statistically significantly lower survival rate (89.9% vs. 96.3%) as well as a higher number of technical complications. (Ha¨ lg et al. 2008) Comparable changes in radiographic bone levels (Ha¨ lg et al. 2008, Wennstro¨m et al. 2004) Confirmed by meta-analysis (Aglietta et al. 2009; Zurdo et al. 2009) Two studies had previously compared the 5-year outcomes of implant-supported FDPs with and without cantilever extensions

Discussion Success and survival rates were 95.5% and 100% (8.2 years follow-up) Prognosis and the marginal bone loss not influenced by: Location Length Opposite dentition (Romeo et al. 2009) a longer observation 針對with cantilever The multivariate analysis

Discussion Fractures of implants with a reduced diameter (3.3 mm) (Ha¨ lg et al. 2008, Romeo et al. 2004) Fractures of implants with a hollow-screw (Bra¨gger et al. 2005)

Discussion 3 implants in each group with increased PPD> 2 mm from the baseline to the follow-up Only to a measurement error Initiation of peri-implant diseases (Tonetti & Claffey 2005)

Conclusion Presence of one mesial or distal cantilever extension in the posterior maxilla or mandible does not jeopardize the marginal bone levels of implants supporting SCs or short-span FDPs after a mean observation period of at least 5 years.

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