Carlos Aparicio

The use of zygomatic implants for prosthetic rehabilitation of the severely resorbed maxilla

In many patients conventional implant treatment cannot be performed in the edentulous maxilla because of extensive bone resorption and the presence of extensive maxillary sinuses, leading to inadequate amounts of bone tissue for anchorage of the implants. The treatment option for these patients has often been some type of bone-augmentation procedure in order to increase the volume of load-bearing bone. Traditionally, the atrophic maxilla has been treated with large bone grafts from the iliac crest, a procedure that requires general anesthesia. The bone grafts have been used as onlays, in combination with a Le Fort I osteotomy, or as maxillary sinus inlays. Implants have been inserted simultaneously or after an initial healing period. Long-term follow-up studies have shown varying degrees of implant survival in grafted bone. A recent literature review based on 23 publications revealed an overall survival rate of 82– 84% after a follow-up time from 12 to 60 months (38). A 10% higher survival rate was seen for implants placed after initial healing of the bone graft than if the implants were placed simultaneously with the bone graft. It can be argued that bone-augmentation procedures are resource demanding, take a long time and may present risks for morbidity of the donor site of the bone graft. It is also obvious that failure rates are higher in grafted than in nongrafted maxillae (17). One alternative to bone grafting that has been considered in the atrophied maxilla is the use of the zygomatic fixture (3, 12, 17). The Brånemark zygomatic fixture is the result of developments of reconstructive techniques for prosthetic rehabilitation of patients with extensive defects of the maxilla caused by tumor resections, trauma and congenital defects (22, 26). The bone of the zygomatic arch was used for anchorage of a long fixture, which, together with ordinary fixtures, could be used as an anchor for epistheses, prostheses and obturators. The technique has enabled sufficient rehabilitation of these patients, with restored function and improved esthetics as a result, and thus has given many patients back a normal social life. The purpose of the present article is to describe the surgical and prosthetic technique, new developments and the clinical outcome zygomatic implantology, based on the literature and on our own experience.

Extrasinus Zygomatic Implants: Three Year Experience from a New Surgical Approach for Patients with Pronounced Buccal Concavities in the Edentulous Maxilla

BACKGROUND The surgical protocol for zygomatic fixtures prescribes an intrasinus approach ideally maintaining the sinus membrane intact and the implant body inside the sinus while gaining access to the zygomatic bone. In the presence of a pronounced buccal concavity, the implant head has to be placed far from the alveolar crest in a palatal direction, which results in a bulky bridge construction. PURPOSE The aim of this study was to report on the preliminary experiences with zygomatic implants placed with an extrasinus approach in order to have the implant head emerging at or near the top of the alveolar crest. MATERIALS AND METHODS Twenty consecutive patients with pronounced buccal concavities in the edentulous posterior maxilla were treated with 104 regular and 36 zygomatic implants as support of fixed dental bridges. Sixteen patients were treated bilaterally and four patients were treated unilaterally. The zygomatic implants were inserted by using an extrasinus surgical approach with the implant body passing from the alveolar crest through the buccal concavity into the zygomatic bone. This enabled placement of the implant head at or close to the alveolar crest. The patients were followed from 36 to 48 months after occlusal loading with a mean follow-up of 41 months. The relation of the zygomatic implants to the crest was measured and compared with a control group of 20 patients treated with conventional placement of zygomatic implants. RESULTS No implants were lost during the study period. No pain, discomfort, or complications related to the extrasinus path of the zygomatic implants were recorded after the initial healing period and up to the 36th-month checkup. The zygomatic implants emerged, on average, 3.8 mm (SD 2.6) palatal to the top of the crest compared with 11.2 mm (SD 5.3) to the conventional technique. CONCLUSION The present 3-year clinical study shows that an extrasinus approach can be utilized when placing zygomatic implants in patients with pronounced buccal concavities in the posterior maxilla. Moreover, the technique results in an emergence of the zygomatic fixture close to the top of the crest, which is beneficial from a cleaning and patient-comfort point of view.

Immediate/Early Loading of Zygomatic Implants: Clinical Experiences after 2 to 5 Years of Follow-up

BACKGROUND Conventional prosthetic treatment of the edentulous and resorbed maxilla with zygomatic implants is a lengthy procedure. Today, immediate/early loading is a clinical reality and it is possible that such protocols could be used also for zygomatic implants. PURPOSE The aim of the present study is to report on the clinical outcomes of immediate/early loading of zygomatic implants for prosthetic rehabilitation of edentulous and severely resorbed maxillary cases. MATERIALS AND METHODS A total of 47 zygomatic and 129 regular implants were placed in 25 consecutive patients with total (N = 23) or partial (N = 2) edentulism in the maxilla. The patients had less than 4 mm of available bone height and width distal to the canine pillars. Straight and angulated abutments and impression copings were attached to the implants during surgery. Impressions and bite registrations were made and 19 patients received a bridge within 24 hours and six patients were rehabilitated within 5 days. Screw-retained full arch restorations were used in 23 patients and cemented in 2 patients. The patients were instructed for a soft diet during 4 months. Follow-up controls were performed at 1, 4, and 12 months and thereafter annually. All patients were followed for at least 2 years and up to 5 years in function. RESULTS All zygomatic implants were stable during the follow-up (cumulative survival rate 100%). One regular implant placed in the pterygoid plate failed after 52 months of loading (cumulative survival rate 99.2%). Apart from fracture of one abutment screw and of anterior teeth in five patients, no other complications were noted. CONCLUSIONS Within the limitations of the present study, it is concluded that immediate/early loading is a viable treatment modality for prosthetic rehabilitation of the severely resorbed maxilla using zygomatic and conventional implants.

The Long-Term Use of Zygomatic Implants: A 10-Year Clinical and Radiographic Report

BACKGROUND The zygoma implant has been an effective option in the short-term management of the atrophic edentulous maxilla. PURPOSE To report on long-term outcomes in the rehabilitation of the atrophic maxilla using zygomatic (ZI) and regular implants (RI). MATERIAL AND METHODS 22 consecutive zygomatic patients in a maintenance program were included. Cumulative survival rate (CSR) of ZI, RI, prostheses, and complications were recorded during, at least, 10 years of loading. Implant mobility was tested using Periotest(®). Sinus health was radiographically and clinically assessed according to Lund-Mackay (L-M) score and Lanza and Kennedy survey, respectively. A satisfaction questionnaire and anatomical measurements were also performed. RESULTS Patients received 22 prostheses, anchored on 172 implants. Forty-one were ZI. Three RI failed (10 years CSR = 97.71%). Two ZI were partly removed due to perimplant infection (10 years CSR = 95.12%). All patients maintained functional prostheses. One patient fractured framework twice. Loosening or fracturing screws happened in 11 patients. Seven patients fractured occlusal material. Four ZI abutments in two patients were disconnected because of uncomfortable prostheses. Alveolar height at the ZI head level on the right and left sides was 2.64 mm and 2.25 mm, respectively. Mean distance of ZI head center to ridge center, on the right and left sides was 4.54 mm and 5.67 mm, respectively. Mean Periotest values (PTv) of ZI were -4.375 PTv and -4.941 PTv before prostheses placement and after 10 years, respectively. Six patients experienced sinusitis 14-127 months postoperatively. 54.55% of the L-M scores did not present opacification (L-M = 0) in any sinus. Osteomeatal obstruction happened in eight patients (two bilateral). Two (9.09%) were diagnosed with sinusitis. Eighty-four percent reported satisfaction levels above 80%. 31.81% reported maximum satisfaction score (100%). CONCLUSIONS The long-term rehabilitation of the severely atrophic maxillae using ZI is a predictable procedure.

Zygomatic implants: indications, techniques and outcomes, and the Zygomatic Success Code

The zygoma implant has been an effective option in the management of the atrophic edentulous maxilla as well as for maxillectomy defects. Brånemark introduced the zygoma implant not only as a solution to obtain posterior maxillary anchorage but also to expedite the rehabilitation process. The zygoma implant is a therapeutic option that deserves consideration in the treatment-planting process. This paper reviews the indications for zygoma implants and the surgical and prosthetic techniques (including new developments) and also reports on the clinical outcome of the zygomatic anatomy-guided approach. An overview of conventional grafting procedures is also included. Finally, a Zygoma Success Code, describing specific criteria to score the success of rehabilitation anchored on zygomatic implants, is proposed.

Zygomatic Implants Placed Using the Zygomatic Anatomy-Guided Approach versus the Classical Technique: A Proposed System to Report Rhinosinusitis Diagnosis

PURPOSE The first aim of this study is to compare the outcomes in rehabilitating the atrophic maxilla using zygomatic implants (ZIs) and regular implants (RIs) using the classical zygomatic technique (CZT) versus the zygomatic anatomy-guided approach (ZAGA). The second goal of this paper is to propose a standardized system to report rhinosinusitis diagnosis. MATERIALS AND METHODS Twenty-two consecutive zygomatic patients operated on from 1998 to 2002 and 80 consecutive zygomatic patients operated on from 2004 to October 2009 were selected. All included patients were in a maintenance program. Survival rates (SRs) of ZI and RI were recorded. Implants were individually tested using Periotest® (Periotest value [PTv], Siemens AG, Bensheim, UK). Sinus health was radiographically and clinically assessed according to Lund-Mackay system and Lanza and Kennedy survey recommended by Task Force on Rhinosinusitis for research outcomes. A satisfaction questionnaire (Oral Health Impact Profile for assessing health-related quality of life in Edentulous adults) and different anatomical measurements were also performed. RESULTS No significant differences (p = .602) were observed with respect to SR between the two groups (95.12% vs 96.79%). Significant differences (p = .000) were found comparing measurements of ZI head distance to the alveolar crest (5.12 ± 2.38 mm vs 2.92 ± 2.30 mm). With the CZT, more palatal emergence of ZI was observed. PTv gave significantly greater stability for the CZT compared with the ZAGA group in both measurements (-4.38 ± 1.75 vs -2.49 ± 4.31, p = .000; -4.94 ± 1.46 vs -3.11 ± 5.06, p = .000). Lund-Mackay score was significantly lower for the ZAGA group (2.38 ± 3.86 vs 0.56 ± 1.26, p = .042). Statistically significant difference (p = .047) regarding the percentage of patients with no signs or symptoms of rhinosinusitis (Lanza and Kennedy test negative and Lund-Mackay score zero) was observed between groups (54.55% vs 76.25%, p = .047). CONCLUSIONS Both procedures had similar clinical outcomes with respect to implant survival. The ZAGA concept is able to immediately rehabilitate the severely atrophic maxillae, minimizing the risk of maxillary sinus-associated pathology. Moreover, less bulky, more comfortable, and easy to clean prostheses are achieved.