Analysis of implant precision in guided surgery: comparison of two methods.

BACKGROUND: Implantology represents the therapy of choice for the rehabilitation of a partially or totally edentulous jaw in a healthy patient. Nowadays, it is possible to exploit of modern preoperative planning software, increasingly precise radiographic examinations (CBCT) and CAD/CAM technologies that allow designing devices directly on the computer to be sent to a milling center which produces the desired product, such as stereolithographic templates. METHODS: The prospective clinical study in question aims to evaluate the accuracy between two different surgical guides using peek and metal guide bushings. Twenty-nine implants were placed: for the control group, 17 3i, T3 implants were used, while for the test group, 12 Xive S plus implants were used. RESULTS: The result obtained shows that the deviations in the distribution of the control group and the test group are the same in the apical-coronal, vestibulo-palatal and mesio-distal direction. For the control group, the mean deviation was 1.394±0.644923 at the entry point of the implants and 1.85655±1.0765 at the most apical point of the implants. For the test group the mean deviation was 1.10157±0.312721 at the entry point of the implants and 1.54514±0.572100 at the most apical point of the implants. CONCLUSIONS: The peek guide bushings have the same deviation as the metal ones. There is no difference in the method used, but precision must be sought in other elements, such as the patient's anatomy and maximum precision in the guide production phase.

Comparison between CBCT superimposition protocol and S.T.A.P. method to evaluate the accuracy in implant insertion in guided surgery.

BACKGROUND: The aim of this study was to evaluate the accuracy of implant placement using static guided surgery. Two methods of measuring accuracy were compared, the superimposition of CBCT and the non-radiological Superimposition Touch Absolute Precision (S.T.A.P.) method. METHODS: In this prospective clinical study 23 implants were placed with static surgical template using a flapless technique and postextractive procedure. Six months after surgery, a postoperative CBCT was performed to assess the position of the implants and at the same time dental impressions were taken for the final prosthesis. The plaster models made at this stage have made it possible to obtain the position of the implants inserted using the probe technology. Preoperative and postoperative data were superimposed, deviations in the three dimensions of the space were calculated. The differences between the two measurement methods were assessed. RESULTS: The study showed no statistically significant differences between the two methods of measuring accuracy at the implant platform level, apex, or angles. The average real deviation detected at the implant platform level is 1.16±0.58 mm with CBCT, 1.22±0.55 mm with the S.T.A.P. method; at the apex level is 1.48±0.98 mm with CBCT, 1.47±0.72 mm with the S.T.A.P. method. The average difference between CBCT and S.T.A.P. method for real deviation is 0.06±0.75 mm at the platform level and 0.007±1.24 mm at the apex level. CONCLUSIONS: The present study showed that measuring accuracy by S.T.A.P. method was comparable to that obtained by CBCT superimposition.

Immediate loading of implants in the aesthetic zone: comparison between two placement timings.

AIM OF THE STUDY: Implant rehabilitation delivered in accordance with the traditional protocol has proven to be highly predictable and acceptable (1). Nevertheless, the application of immediate loading on post-extraction implants, especially for aesthetic zones, has now considerably increased (2). The aim of this work is to illustrate the immediate loading of implants placed in the aesthetic zone through tapered design fixtures with microgeometry of a high degree of porosity inserted at the same time or 4-8 weeks from dental avulsion (TSA® Advance, Phibo®). MATERIALS AND METHODS: A total of 15 implant fixtures of which 8 at an interval of 4-8 weeks from extraction (type 2) and the remaining according to the immediate post-extraction technique (type 1) were positioned. All implants were prosthesized within 24 hours from the placement. Definitive crowns replaced provisional restorations after 20-24 weeks. After 4 and 12 months from implant insertion, the following parameters were assessed: X-ray image, pain, mobility or suppuration, soft tissue condition and aesthetic appearance. RESULTS: Percentage of osseointegration was 93.75%, and 53.5% of the osseointegrated fixtures was type 2. No statistically significant difference between the mean ISQ values for implants of type 1 and 2 both in the post-operative period and after 12 months was evident, indicating that the timing of insertion did not affect the achievement of stability for the implant fixtures tested in our study. Immediate post-extraction implants showed a greater propensity for gingival recession and a peri-implant radiolucency greater than those placed at an interval of 4-8 weeks. The values obtained for the PES/WES and the subjective evaluation of the analyzed sample showed the considerable aesthetic value and the high level of satisfaction guaranteed by the implant technique illustrated. CONCLUSION: Although well-designed, high quality, randomized clinical trials are still needed as well as the requirement to establish a common, complete, and reproducible index for the evaluation of aesthetic outcome, immediate/early placement and loading of a single TSA® Advance, Phibo® may be considered a valuable and predictable option in terms of implant success as well as hard and soft tissue stability.

Central osteoma of the maxilla: implant rehabilitation with immediate loading in fresh extraction socket.

AIM OF THE STUDY: Solitary central osteomas of the jaw seem to be especially rare lesions; since 1955, only 12 cases have been reported and 4 of these were located in the maxilla. Osteomas are benign osteogenic lesions considered as real tumours but without infiltrative or metastatic potential. Their growth potential is usually limited, but certain rare and large cases of peripheral osteoma are described in literature. Although surgery is recommended, there are no reports of malignant transformation. In this study, we describe successful implant rehabilitation in a patient with a central osteoma of the maxilla with immediate loading in a fresh extraction socket. MATERIALS AND METHODS: The report concerns a 33-year-old woman with a compromised deciduous first molar in the left premolar region of the maxilla; an asymptomatic bony expansion of the palatal and vestibular sides of the left canine/premolar/molar area of the maxilla and by radiograph revealed a well-defined radiopaque mass. An immediate non-occlusal loading was performed, and complete loading of the implant was completed five months later. DISCUSSION AND CONCLUSION: The pathogenesis of these osteomas is unclear. Several authors reported a clear history of traumatic events, but others had no history of previous trauma or contributory medical factors. Since in our case no cancer growth happened over a period of more than four years, we decided to perform an immediate loading procedure during the implant rehabilitation. The outcome was successful.

Surgical protocol in patients at risk for bisphosphonate osteonecrosis of the jaws: clinical use of serum telopetide CTX in preventive monitoring of surgical risk.

AIM: This study investigates the association between cross linked C-terminal telopetide test (CTX) and individual surgical risk of osteonecrosis in patients taking oral bisphosphonates. MATERIALS AND METHODS: 32 patients receiving bisphosphonate were treated surgically. Patients were divided into three groups according to type of drug administrated and were subjected to a treatment of oral surgery, such as simple tooth extractions and extraction of all residual teeth of the oral cavity, upon evaluation of CTX values and antibiotic prophylaxis. RESULTS: Within the sample of 32 patients, 12 patients had been treated with bisphosphonates for several years and none developed osteonecrosis of the jaw upon surgery. As for CTX, patients treated with oral bisphosphonates showed a mean value of serum Ctelopetides of 0.2869 ng/ml. The mean value of CTX did not differ significantly between patients taking oral bisphosphonates and healthy patients not treated with bisphosphonates. CONCLUSION: None of the patients subjected to preoperative antibiotic prophylaxis developed osteonecrosis of the jaw after surgery. The pharmacological and surgical protocol tested appeared valid in the prevention of osteonecrosis associated to bisphosphonates.

Case control study to assess the possibility of decrease the risk of osteoradionecrosis in relation to the dose of radiation absorbed by the jaw.

AIMS: the assessment of the limit dose for the organs at risk in external radiotherapy is a fundamental step to guarantee an optimal risk-benefit ratio. The aim of this study was to assess, through contouring the single dental cavities, the absorbed radiation dose on irradiated alveolar bones during the treatment of cervico-facial tumours, so as to test the correlation between the absorbed dose of radiation at alveolar level and the level of individual surgical risk for osteonecrosis. MATERIALS AND METHODS: we selected 45 out of 89 patients on the basis of different exclusion criteria. Nine of these patients showed evidence of osteoradionecrosis. The patients were treated either with 3D conformational radiation therapy (3D-CRT) or with intensity-modulated radiation therapy (IMRT), there after alveolar bones were contoured using computed axial tomography (CAT scans) carried out following oncological and dental treatment. The dose-volume histograms (DVH) were obtained on the basis of such data, which included those relating to the dental cavities in addition to those inherent to the tumours and the organs at risk. RESULTS: all patients, irrespective of type of treatment, received an average of 60 to 70 grays in 30/35 sittings. The patients treated with IMRT showed higher variation in absorbed radiation dose than those treated with 3D-CRT. The alveolar encirclement allowed the assessment of the absorbed radiation dose, and consequently it also allowed to assess the individual surgical risk for osteonecrosis in patients with head and neck tumours who underwent radiography treatment. CONCLUSIONS: the study of DVH allows the assessment of limit dose and the detection of the areas at greater risk for osteoradionecrosis before dental surgery.

Multiple systemic diseases complicated by bisphosphonate osteonecrosis: a case report.

AIMS: this work aims at demonstrating that multiple systemic conditions, in association with the development of bisphosphonate associated osteonecrosis of the jaw (ONJ), increase the risk of complications and may lead to hospitalization. For this reason the dental approach to patients with multisystem disease should be carefully managed by a team of specialists. CASE REPORT: a case of mandibular necrosis associated with intake of oral bisphosphonates in a complex systemic context is described. RESULTS AND DISCUSSION: many different diseases and systemic conditions may draw the line at oral surgery. Multiple treatments (e.g. antithrombotic, calcium channel blockers, diuretics, antibiotics and bisphosphonates) can alter the normal physiological response to tissue healing. CONCLUSIONS: patients taking bisphosphonates for more than three years (i.e. the term over which the risk of ONJ increases according to the literature, in presence of complex systemic situations, need to be carefully managed during the pre-operative, peri-operative and postoperative phases through a synergistic collaboration among different kind of specialists.

Implant-supported rehabilitation of a patient with mandibular ameloblastoma.

OBJECTIVES: this report describes the masticatory implant- supported rehabilitation of a patient undergoing resection for mandibular ameloblastoma. CASE REPORT: in the reported case the patient underwent resection and reconstruction with a fibula flap for masticatory rehabilitation of 7 implants at the level of the mandible. DISCUSSION: ameloblastoma is a benign locally invasive tumor of maxillary bones that often causes facial disfigurement. The dental management of the patient requires a collaboration of various specialists such as anesthetists, maxillofacial surgeons, and dentists. CONCLUSIONS: in patients with oral cancers such as ameloblastoma, the correct planning of surgery for the tumor resection as well as prosthetic rehabilitation are crucial. Osseointegrated implants open a new perspective of treatment to improve the quality of life of patients resected for cancer.

Implant-supported denture rehabilitation on a hemimandibulectomized patient: a case report.

AIM OF THE STUDY: the treatment of oral cancer requires different surgical approaches such as marginal or segmental mandibular resection in order to allow a safe removal of the neoplastic lesion. The aim of this work is to evaluate the efficacy of an implant-supported denture rehabilitation for restoring oral function and facial appearance on a hemimandibulectomized patient. MATERIALS AND METHODS: the patient was a 64 years old man, hard smoker and moderate drinker. Due to a jaw neoplastic lesion, he underwent a hemimandibulectomy, followed by the insertion of 4 implant fixtures at the chin cap symphysis site. The denture rehabilitation consisted in an over-denture mounted onto a bar furnished by a condylar eminence in articulation with the glenoid fossa of the upper denture. RESULTS: this type of implant-supported denture rehabilitation allows the recovery of the masticatory function and the mandibular reposition with a satisfactory restoration of the proper facial symmetry and appearance. CONCLUSION: in the edentulous patient implant-supported denture with artificial condyle allows the recovery of the masticatory function without the need of additional operations to re-establish the temporomandibular joint anatomy. It is currently considered as a low invasive technique with very low risk of side effects.

Osteointegration in oncologic patients: a case report.

OBJECTIVE: the present case report aims at illustrating how implant-prosthetic rehabilitation in patients with oral cancer resection aids to improve their quality of life. MATERIAL AND METHODS: a patient with verrucous squamous cell carcinoma of the mandible was treated with surgery and rehabilitation with three interforaminal dental implants and Toronto bridge. Three years after treatment, because of cancer recurrence, a segment of jaw and one of the three mandibular implants were removed. The histological examination showed healthy bone contact to implant surface, despite proximity to the neoplastic area. RESULTS: the case shows the maintainance of the osseointegration implants despite the cancer recurrence in the same area. CONCLUSIONS: endosseous implants represent a useful and valid tool for the prosthetic rehabilitation of cancer patients. Long-term effects of implant-prosthetic rehabilitation in patients with cancer still need to be verified. It would be interesting to confirm the data obtained by numerical studies of representative samples.