Intraoral Autogenous Vs Allogeneic Block Grafts in Preparation for Dental Implants Placement: A Retrospective Cohort Study

Atrophy is a common problem many partially edentulous patients face when dealing with potential restorative options. Although highly successful, autogenous grafting involves a second surgical site with potential morbidities and increased healing time for the patient. This study compares the complications rates of two common block grafting techniques using autogenous and allogeneic grafts.

This study is a ten-year retrospective cohort study with chart review of outpatients seen at the Rutgers School of Dental Medicine (Newark, NJ) for alveolar bone grafting. The procedures were all completed by a chief or senior level OMFS resident under the direct supervision by one of the two senior authors (HFB, BEZ) who insured a consistent and standard technique. All patients included in the study underwent autogenous block grafting (obtained from the ramus or the symphysis) or allograft block grafting (Puros, Zimmer, Warsaw, IN; Community Tissue Services [CTS], Kettering, OH). Variables reviewed included: age, gender, pertinent medical history, use of tobacco, recipient site location, graft type (autogenous vs allograft), type of allograft use (freeze dried [CTS] vs solvent preserved [Puros]), use of membrane, complications from both donor or recipient site including  hypoesthesia, overall graft integration,  number of  implants placed, post placement complications and presence of final restorations. 

We created a database using Excel (Microsoft 2010) with appropriate checks to identify errors. Univariate analyses were used to identify risk factors associated with total complications. Risk factors with p-values ≤ 0.05 based on univariate logistic regression analyses and biologically relevant variables (such as age at time of grafting) were entered into a multivariate logistic regression model. Risk factors with p-values ≤ 0.05 were considered significant in the multivariate model. Statistical computing with SAS-PC (Version 9.4, Cary, NC) was used for statistical analysis.

There were 91 grafted sites, 43 autogenous grafts (47.2%) and 48 allogeneic grafts (52.7%) in 72 patients, (47 females, 25 males, with a mean age of 50.25 years.) Autogenous block graft failures were 2/43 (4.65%) and all located in the posterior mandible. Allogeneic block graft failures were 10/48 (20.4%). 7 of these were located in the posterior mandible. Implants were placed in 41/43 (95.3%) of autogenous grafts and 39/48 (81.25%) allogeneic grafts. Mental nerve hypoesthesia was reported in 15/35 (42.9%) patients undergoing autografts, of which 8 (22.9%) resolved during the postoperative period.

Clinically significant risk factors for graft loss were: patient age (with a 13.8% increase in graft loss for increment of per unit age year). In the multivariate model, the overall frequency of graft loss was statistically higher in the allograft group with an odds ratio of 5.6 (95% confidence interval: 1.13 - 27.0) (P=0.0339) compared to the autograft group. Grafts placed in the posterior mandible were 88.5% more likely to have complications (odds ratio of 8.7, 95% confidence interval: 1.04 - 71.4) (P=0.045) than anterior maxilla augmentations. Type of allograft (freeze-dried vs solvent preserved) and use of membrane were not statistically associated with increased complications rates.

The results of this study confirm the high success rate of autogenous block grafts, although rates of neurosensory deficits remain problematic. Block allografts augmentations performed very well, except in the posterior mandible where high rates of failures were noted.

Peleg M, Sawatari Y, Marx RN, Santoro J, Cohen J, Bejarano P, Malinin T “Use of  corticocancellous bone blocks for augmentation of alveolar bone defects.” The International Journal of Oral and Maxillofacial Implants  25(1):153-162 (2010) . Print.

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