Fully Guided Zygomatic Implant Surgery.

INTRODUCTION: Rehabilitating a severely atrophic maxilla is a complex procedure. In case of severe resorption, zygomatic implants are indicated and loading of the implants at the end of the surgery is desirable. We present a new method by means of guided surgery for the placement of zygomatic implants, using specially designed metal templates that should be supported by bone. METHODS: The treatment planning for completely guided prosthetic rehabilitation of the maxilla with zygomatic implants was digitally performed. A radiographic template was designed for the prosthetic treatment planning. A surgical template was used to replicate the digitally planned steps in vivo. RESULTS: The procedure ended with the positioning of a custom-made temporary prosthesis. This method can reduce the surgery duration, simplify the procedure, and optimize the outcome. It requires equal cooperation among technicians, prosthodontists, and surgeons. Nineteen out of twenty patients included in the study presented successful implants and prosthesis at the moment of analysis. CONCLUSIONS: The present approach addressed the needs for zygomatic-implant surgery. The surgical and prosthetic plan, position, emergence, the shape of the implants, the position of the temporary prosthesis, the inter-arch relationships, and surgical templates were designed in a completely virtual environment and performed by the surgeon on stereolithographic models beforehand. Consequently, the surgical procedure was considerably simplified.

Reconstruction of severely atrophic jaws using homografts and simultaneous implant placement: a retrospective study.

In the past decade, several investigators have reported that implants inserted in autografts in the same operation (ie, simultaneously inserted implants [SIIs]) have achieved excellent results. However, no report regarding SIIs placed in fresh frozen bone (FFB) is available. Thus, the authors planned a retrospective study on a series of SIIs placed in homologue FFB (but not immediately loaded) to evaluate their clinical outcome. In addition, a comparison with implants inserted in FFB in a second stage (ie, delayed inserted implants) was performed. Seventeen patients were grafted with FFB, and 48 implants were inserted in the same operation. Implant diameter and length ranged from 3.25 to 4.0 mm and from 10.0 to 15 mm, respectively. Data were compared with 302 implants inserted in FFB in a second operation during the same period in 64 patients. Analyzing SIIs, it was noted that only 3 implants were lost (ie, survival rate [SVR] = 93.7%), and no differences were detected among the studied variables by using lost implants as a predictor of clinical outcome. On the contrary, by using crestal bone resorption around the implant's neck and specific cutoff values, it was possible to demonstrate that prosthetic restoration (ie, removable overdentures) correlated with a statistically significant lower delta insertion abutment junction (ie, reduced crestal bone loss) and thus with a better clinical outcome. By comparing SIIs with implants inserted in a second stage in FFB, a better outcome for delayed implants was demonstrated. Implants inserted simultaneously with FFB grafts had a high survival and success rate. SIIs inserted in FFB can be considered reliable devices, although a higher marginal bone loss is to be expected when fixed prosthetic restorations are used. Implants inserted in a second surgical stage have a better SVR and success rate than SIIs.

Retrospective study of standard-diameter implants inserted into allografts.

PURPOSE: In the last decade, several investigators reported that standard-diameter implants (SDIs) achieved excellent results. However, no report is available regarding SDIs inserted into fresh-frozen bone (FFB). We conducted a retrospective study on a series of SDIs (diameter, 3.75 mm) inserted into homologous FFB to evaluate their clinical outcome. MATERIALS AND METHODS: The SDIs inserted with FFB were analyzed. Several variables were investigated regarding patients, anatomic sites, implants, and prosthetic restoration. Implant failure and peri-implant bone resorption were considered predictors of clinical outcome. A Kaplan-Meier algorithm and Cox regression were performed to detect those variables statistically associated with clinical outcomes. RESULTS: One hundred thirty-three SDIs were inserted in 41 patients. Implant length ranged from 10 to 15 mm. Implants were inserted to replace 6 incisors, 13 cuspids, 60 premolars, and 54 molars. The mean follow-up was 23 months. Only 1 of 133 implants was lost (ie, survival rate=99.2%), and no differences were detected among study variables. On the contrary, crestal bone resorption correlates with type of prosthetic restoration, with a better outcome for removable dentures. CONCLUSION: The SDIs had high survival and success rates, similar to those reported in previous studies of 2-stage procedures in nongrafted bone. The SDIs inserted into FFB are reliable, although a greater marginal bone loss is to be expected if fixed prosthetic restorations are used.

Iliac crest fresh frozen homografts used in pre-prosthetic surgery: a retrospective study.

In the case of severe jaw atrophy several options are available to restore the alveolar crest. Aim of the present study was to evaluate the resorption over time of homologous fresh frozen bone used to restore the alveolar ridge. Specifically factors influencing (1) graft survival, (2) type, and (3) degree of bone resorption were evaluated. One hundred and thirteen maxillae and 27 mandibles were grafted. The surgical techniques used were 102 inlay, 27 onlay, and 11 veneer. Measurements were taken on pre-operative, post-operative, and follow-up radiographs. Data were processed by using three statistical methods: Kaplan-Meier algorithm, Cox regression, and curve estimation. As regards graft survival, Cox regression output showed a statistically significant effect only on surgical technique (P = 0.0312) and Kaplan-Meier algorithm demonstrated a worse outcome for veneer surgical technique (Log rank test = 0.0242). The Curve estimation demonstrated an inverse correlation between degree of bone resorption over time, with a progressive decrease. In conclusion FFB is a reliable material for alveolar bone restoration with a predicable average of resorption.

Mandibles grafted with fresh-frozen bone: an evaluation of implant outcome.

In the last decade several studies have been performed to evaluate the clinical outcome of implants inserted into grafted mandibles with autologous bone, but none is available on mandibles grafted with fresh-frozen bone. Thus, we planned a retrospective study on a series of implants inserted into homologue fresh-frozen bone to evaluate their clinical outcome. Twenty-one patients were operated on, 28 onlay grafts were inserted into the mandible, and 63 implants placed. Patients had total and partial edentulism in 11 and 10 cases, respectively. The mean follow-up was 20 months. No or reduced crestal bone resorption was considered an indicator of success rate to evaluate the effect of several host-, implant-, and occlusal-related factors. The difference between the implant-abutment junction and the bone crestal level was defined as the implant abutment junction (IAJ) and calculated at the time of operation and during follow-up by means of radiographs. Delta IAJ, the difference between theIAJ at the last check-up and the IAJ recorded just after the operation, were stratified according to variables of interests. Kaplan-Meier algorithm and Cox regression were then performed to detect those variables statistically associated with the delta IAJ. Only 2 of 63 implants were lost (i.e., survival rates = 96.8%) and no differences were detected among the studied variables. On the contrary, Cox regression showed that prosthetic restoration (i.e., removable dentures) was the only factor correlated with a statistically significant lower delta IAJ (i.e., reduced crestal bone loss) and thus a better clinical outcome. Implants inserted into mandibles grafted with fresh-frozen bone allografts have high survival rates and success rate, which are comparable with those obtained with autologous iliac crest bone grafts.

CaPO4 blasted implants inserted into iliac crest homologue frozen grafts.

In the last decade, some investigations have reported that the resorbable blast media surface (also named CaPO4 blasted implants [CaPO4-Bls]) has achieved excellent results. However, no report regarding CaPO4-Bls inserted into fresh frozen bone (FFB) is available. Thus, we planned a retrospective study on a series of CaPO4-Bls inserted into FFB to evaluate their clinical outcome. In the period between December 2003 and December 2006, 16 patients (10 females and 6 males, median age of 55 years) were operated on, and 76 CaPO4-Bls were inserted. The mean implant follow-up was 23 months. Implant diameter and length ranged from 3.25 to 4.5 mm and from 11.5 to 15 mm, respectively. Implants were inserted to replace 7 incisors, 11 cuspids, 31 premolars, and 27 molars. Only 1 out of 76 implants was lost (i.e., survival rate [SVR] = 98.7%), and no differences were detected among the studied variables. When peri-implant crestal bone resorption was used as an indicator of clinical success (i.e., success rate), it was possible to identify some variables that correlated with a better clinical outcome. Specifically, Cox regression showed that removable prosthetic restoration and longer implant length correlated with a statistically significant lower delta implant abutment junction (IAJ; i.e., reduced crestal bone loss) and thus a better clinical outcome. In this study, CaPO4-Bls had high survival and success rates, similar to those reported in previous reports of 2-stage procedures in nongrafted bone. CaPO4-Bls inserted into FFB are reliable devices, although greater marginal bone loss occurs when fixed prosthetic restorations and short implants are used.

A 2-year follow-up study on standard length implants inserted into alveolar bone sites augmented with homografts.

OBJECTIVE: In the last decade, several investigators have reported that standard length implants (SLIs) have achieved excellent results but no report regarding SLIs (i.e. SLI, length=13 mm) inserted into alveolar bone sites previously augmented with frozen bone (FB) is available. The aim of this study was to evaluate the clinical outcome of SLIs inserted into alveolar bone sites previously augmented with FB. PATIENTS AND METHODS: The survival and success rate of standard dental implants was evaluated after surgical placement into alveolar bone sites previously augmented with FB. The distance between Implant Abutment Junction and crestal bone level (i.e. delta IAJ) was measured to evaluate the peri-implant bone loss over time. Kaplan-Meier algorithm and Cox regression were used. RESULTS: The implant survival rate was 97.6% and no differences were detected among the studied variables by using implant loss. On the contrary, the Cox regression showed that implant surface (i.e. sandblasted and acid-etched-SLA- and CaPO(4)ceramic-blasted implants, p=0.0037), graft site (i.e. maxilla, p=0.0438) and prosthetic restoration (i.e. removable dentures, p=0.0003) correlated with a statistically significant reduced crestal bone loss (i.e. success rate). CONCLUSION: SLIs had a high survival and success rate similar to those reported in previous studies of two-stage procedures in non-grafted bone. FB is a reliable material for alveolar reconstruction and implant insertion.

A retrospective study on 287 implants installed in resorbed maxillae grafted with fresh frozen allogenous bone.

BACKGROUND: Several studies have been performed to evaluate the clinical outcome of implants inserted into maxillae grafted with autogenous bone but few reports have focused on maxillae grafted with fresh-frozen allogenous bone (FFAB). PURPOSE: The purpose of this study is to retrospectively evaluate the clinical outcome of implants installed in resorbed maxillae augmented with FFAB. MATERIALS AND METHODS: A total of 69 patients whom had been treated with FFAB grafts to their maxillae and implant placement 4 to 6 months later were retrospectively evaluated. Edentulism was total and partial in 22 and 47 cases, respectively. A total of 287 implants of various systems had been used. A life table analysis was performed. Marginal bone loss was calculated in radiographs. RESULTS: Five of the 287 implants were lost, giving a survival rate (SVR) of 98.3% over a mean follow-up time of 26 months. The marginal bone resorption at the implants was 1.68 mm (SD = 0.44) after 1 year and 1.85 mm (SD = 0.98) after 4 years. The cumulative success rate based on defined criteria was 96% in the first year but decreased to 40% at 4 years because of marginal bone loss. The Kaplan-Meier algorithm demonstrated a better outcome for female patients, removable dentures, and total edentulism. No differences were detected among diameters, lengths, and implant site. CONCLUSION: Implants placed in FFAB showed a high SVR similar to that reported in previous studies on maxillae grafted with autogenous iliac crest bone. Although our data point to more marginal bone loss in partially edentulous patients and for fixed prosthetic restorations, the use of FFAB for reconstruction of the atrophic jaw prior to implant placement can be considered as a reliable alternative to autogenous bone.

Implants inserted into homografts bearing fixed restorations.

PURPOSE: In the last decade several studies have evaluated the clinical outcome of implants inserted into autografts and rehabilitated with fixed restorations in either one- or two-step surgical protocols. However, no study has investigated implants placed into homografts; thus, a case series analysis was performed to verify the clinical outcome of implants inserted into fresh frozen bone (FFB) and bearing fixed prosthetic restorations. MATERIALS AND METHODS: Fifty-eight patients underwent iliac crest homograft transplants and 238 implants were inserted. Seventy-one double-etched, 19 sandblasted and acid-etched-1 (SLA1), 10 grit-blasted and acid-etched, 73 anodic oxidized, 39 CaPo4 ceramic-blasted, 19 SLA2, and seven additional implants of various types were used. Implant diameter and length ranged from 3 to 5 mm and from 7 to 16 mm, respectively. Implants were inserted to replace 15 incisors, 14 canines, 102 premolars, and 107 molars. A total of 111 restorations were performed. RESULTS: No implants were lost. Cox regression analysis showed that implant type and type of edentulism directly correlated with a lower bone resorption and thus had a better clinical outcome and success rate. CONCLUSION: Implants bearing fixed restorations and inserted into FFB have higher survival and succes rates compared to those placed in nongrafted and grafted jaws reported in previous studies.

Osseotite implants inserted into fresh frozen bone grafts.

BACKGROUND: In the last decade, several investigators have reported that double etched implants have achieved excellent results. However, no report regarding double etched implants inserted into fresh frozen bone is available. AIMS: We planned to perform a retrospective study on double etched implants inserted into fresh frozen bone grafts. SETTING AND DESIGN: 28 patients (17 females and 11 males with a median age of 52 years) were operated on and 114 double etched implants inserted. Implant diameter and length ranged from 3.25 to 5.0 mm and from 10.0 to 15 mm, respectively. Implants were inserted to replace 14 incisors, 5 cuspids, 47 premolars and 48 molars. RESULTS: Since only 4 out of 114 implants were lost (i.e. Survival Rate SVR = 96.5%) and no statistical differences were detected among the studied variables. The type of prosthetic restoration (i.e. fixed prostheses) correlated with a statistically significant lower delta Implant Abutment Junction (i.e. reduced crestal bone loss) and thus a better clinical outcome. CONCLUSION: Double etched implants inserted into fresh frozen bone had a high survival and success rate similar to those reported in previous studies of two-stage procedures in non-grafted bone, although a higher marginal bone loss has to be expected when removable prosthetic restorations are used.

Clinical outcome of narrow diameter implants inserted into allografts.

OBJECTIVE: Narrow diameter implants (NDI) (i.e. diameter <3.75 mm) are a potential solution for specific clinical situations, such as reduced interradicular bone, thin alveolar crest and replacement of teeth with small cervical diameter. NDI have been available in clinical practice since the 1990s, but only few studies have analyzed their clinical outcome and no study have investigated NDI inserted in fresh-frozen bone (FFB) grafts. Thus, a retrospective study on a series of NDI placed in homologue FFB was designed to evaluate their clinical outcome. MATERIAL AND METHODS: In the period between December 2003 and December 2006, 36 patients (22 females and 14 males, mean age 53 years) with FFB grafts were selected and 94 different NDI were inserted. The mean follow-up was 25 months. To evaluate the effect of several host-, surgery-, and implant-related factors, marginal bone loss (MBL) was considered an indicator of success rate (SCR). The Kaplan Meier algorithm and Cox regression were used. RESULTS: Only 5 out of 94 implants were lost (i.e. survival rate - SVR 95.7%) and no differences were detected among the studied variables. On the contrary, the Cox regression showed that the graft site (i.e. maxilla) reduced MBL. CONCLUSIONS: NDI inserted in FFB have a high SVR and SCR similar to those reported in previous studies on regular and NDI inserted in non-grafted jaws. Homologue FFB is a valuable material in the insertion of NDI.

Implants inserted in fresh-frozen bone: a retrospective analysis of 88 implants loaded 4 months after insertion.

OBJECTIVE: In the previous decade, several reports have been published regarding implants inserted in autografts, but none have analyzed implants inserted in fresh-frozen bone allografts. Thus, a retrospective study was planned to verify if 4-months' delay from grafting to implant insertion is a safe period before prosthetic rehabilitation of implants placed in fresh-frozen bone allografts. METHOD AND MATERIALS: Between December 2003 and December 2006, 22 patients (10 women and 12 men with a median age of 51 years) underwent grafting with horizontal augmentation without membrane and 88 implants inserted thereafter. The mean implant follow-up was 27 months. Implants used were 30 double etched (3i, Osseotite, Biomet), 10 SLA1 (Astratech), 26 anodic oxidized (Nobel Biocare), 12 CaPO4 ceramic-blasted (Lifecore Biomedical), 7 SLA2 (Sweden and Martina Spa), 2 ITI (Straumann), and 1 Biotec (Povolaro di Dueville). Implant diameter and length ranged from 3.25 to 5.0 mm and from 8.0 to 15.0 mm, respectively. Implants were inserted to replace 10 incisors, 7 canines, 36 premolars, and 35 molars. RESULTS: No implants were lost (ie, survival rate = 100%). No difference was detected when comparing implants loaded after 4 months versus those loaded after 6 or more months (209 implants). CONCLUSION: Four-months' delay from grafting to implant insertion is a safe period to obtain a high survival rate and success rate for implants inserted in fresh-frozen bone.

Clinical outcome of narrow diameter implants inserted into allografts

OBJECTIVE: Narrow diameter implants (NDI) (i.e. diameter <3.75 mm) are a potential solution for specific clinical situations, such as reduced interradicular bone, thin alveolar crest and replacement of teeth with small cervical diameter. NDI have been available in clinical practice since the 1990s, but only few studies have analyzed their clinical outcome and no study have investigated NDI inserted in fresh-frozen bone (FFB) grafts. Thus, a retrospective study on a series of NDI placed in homologue FFB was designed to evaluate their clinical outcome. MATERIAL AND METHODS: In the period between December 2003 and December 2006, 36 patients (22 females and 14 males, mean age 53 years) with FFB grafts were selected and 94 different NDI were inserted. The mean follow-up was 25 months. To evaluate the effect of several host-, surgery-, and implant-related factors, marginal bone loss (MBL) was considered an indicator of success rate (SCR). The Kaplan Meier algorithm and Cox regression were used. RESULTS: Only 5 out of 94 implants were lost (i.e. survival rate - SVR 95.7 percent) and no differences were detected among the studied variables. On the contrary, the Cox regression showed that the graft site (i.e. maxilla) reduced MBL. CONCLUSIONS: NDI inserted in FFB have a high SVR and SCR similar to those reported in previous studies on regular and NDI inserted in non-grafted jaws. Homologue FFB is a valuable material in the insertion of NDI.