A clinico‐pathological comparison between mandibular and maxillary ameloblastomas in Sri Lanka

J Oral Pathol Med (2010) 39 : 236–241 Background: The aim of this retrospective study was to analyse the relative prevalence and the clinico‐pathological characteristics of mandibular and maxillary ameloblastomas in Sri Lanka. Methods: Clinico‐pathological features of a total of 286 cases of ameloblastomas were analysed. Results: Out of the 286 cases, 87.8% (251/286) of ameloblastomas occurred in the mandible, while 10.8% (31/286) occurred in the maxilla indicating a ratio of 8:1. In the mandible, 54% (136/251), 40% (100/251) and 6% (15/251) of tumours and in the maxilla, 23% (7/31), 48% (15/31) and 29% (9/31) of tumours were solid/multicystic ameloblastomas (SMA), unicystic ameloblastomas (UA) and desmoplastic ameloblastomas (DA) respectively. No gender predilection was observed in mandibular or maxillary ameloblastomas. Most of the lesions were observed in 2nd to 5th decade of life (mean age 33.2 years). No differences between mandibular and maxillary ameloblastomas were observed with reference to overall cellularity and mitotic activity. Solid/multicystic and UAs showed a predilection to posterior region, while DAs were frequently found in the anterior region of both jaws. Twenty‐one percentage (60/286) of ameloblastomas presented with recurrences, and 94% (34/36) of these recurrences were observed in cases treated conservatively. Conclusion: In conclusion, mandibular ameloblastomas were more prevalent than maxillary ameloblastomas, while no differences were observed in age or gender distribution between the mandibular and maxillary ameloblastomas. However, higher proportion of DAs and UAs was observed in the maxilla compared with some of the other studies. SMA should be treated with resection to prevent recurrences.     

Evidence‐Based Criteria for Differential Treatment Planning of Implant Restorations for the Maxillary Edentulous Patient

Since the introduction of the endosseous concept to North America in 1982, there have been new permutations of the original ad modum Branemark design to meet the unique demands of treating the edentulous maxilla with an implant restoration. While there is a growing body of clinical evidence to assist the student, faculty, and private practitioner in the algorithms for design selection, confusion persists because of difficulty in assessing the external and internal validity of the relevant studies. The purpose of this article is to review clinician‐ and patient‐mediated factors for implant restoration of the edentulous maxilla in light of the hierarchical level of available evidence, with the aim of elucidating the benefit/risk calculus of various treatment modalities.     

CNC‐Milled Titanium Frameworks Supported by Implants in the Edentulous Jaw: A 10‐Year Comparative Clinical Study

Background: No long‐term clinical studies covering more than 5 years are available on Computer Numeric Controlled (CNC) milled titanium frameworks. Aim: To evaluate and compare the clinical and radiographic performance of implant‐supported prostheses provided with CNC titanium frameworks in the edentulous jaw with prostheses with cast gold‐alloy frameworks during the first 10 years of function. Material and Methods: Altogether, 126 edentulous patients were by random provided with 67 prostheses with titanium frameworks (test) in 23 maxillas and 44 mandibles, and with 62 prostheses with gold‐alloy castings (control) in 31 maxillas and 31 mandibles. Clinical and radiographic 10‐year data were collected for the groups and statistically compared on patient level. Results: The 10‐year prosthesis and implant cumulative survival rate was 95.6% compared with 98.3%, and 95.0% compared with 97.9% for test and control groups, respectively (p > .05). No implants were lost after 5 years of follow‐up. Smokers lost more implants than nonsmokers after 5 years of follow‐up (p < .01). Mean marginal bone loss in the test group was 0.7 mm (SD 0.61) and 0.7 mm (SD 0.85) in the maxilla and mandible, with similar pattern in the control group (p > .05), respectively. One prosthesis was lost in each group due to loss of implants, and one prosthesis failed due to framework fracture in the test group. Two metal fractures were registered in each group. More appointments of maintenance were needed for the prostheses in the maxilla compared with those in the mandible (p < .001). Conclusion: The frequency of complications was low with similar clinical and radiological performance for both groups during 10 years. CNC‐milled titanium frameworks are a viable alternative to gold‐alloy castings for restoring patients with implant‐supported prostheses in the edentulous jaw.     

Immediate functional loading of TiOblast dental implants in full‐arch edentulous maxillae: a 3‐year prospective study

Introduction: Immediate functional loading of dental implants for full‐arch restoration is a patient‐friendly approach, shown to be feasible with a good long‐term prognosis in a completely edentulous mandible. For the complete restoration of the maxilla, acceptable long‐term clinical follow‐up is lacking or based on case reports rather than on prospective studies. Objectives: This prospective mono‐centre study reports the 3‐year outcome of immediately functionally loaded Astra Tech Dental implants in completely edentulous maxillae based on clinical survival and success based on radiographical assessment of bone level. Material and methods: One hundred and ninety‐five Astra Tech TiOblast surface fixtures were installed in 25 consecutively treated patients (age range: 42–76 years), of whom eight were smokers, 12 had a confirmed history of periodontitis and six had poor bone quality normally deemed for delayed loading. Fixtures and abutments were inserted in a one‐stage procedure and functionally loaded within 24 h with a 10‐unit provisional glass‐fibre or metal‐reinforced screw‐retained restoration. After 6 months, each implant was checked for stability using a manual torque of 20 N cm and the provisional restoration was replaced by a 10–12‐unit screw‐retained metal–ceramic or metal–resin cantilever bridge. Bone level was assessed radiographically from the day of surgery up to 3 years and used to calculate mean bone loss at the patient level and individual implant success. Results: No failures occurred in implants or prostheses, the total survival rate being 100%. Mean marginal bone loss was 0.58 mm (SD 0.58); 0.6 mm (SD 0.53); 0.63 (SD 0.61); and 0.72 (SD 0.63) after 6 and 12 months, and 2 and 3 years, respectively, yielding a 100% success at the patient level. Wilcoxon's signed ranks test showed only statistically significant bone loss between baseline and 6 months and a steady‐state condition during all other intervals. At the individual fixture level, 82% lost <1 mm marginal bone between baseline and 1 year. After 3 years, 86% have <1.5 mm total bone loss and can be considered a success. The fixtures expressing more bone loss were all inserted in smokers. Conclusion: Immediate loading of a full‐arch maxillary bridgework on 7–9 Astra Tech TiOblast implants is a predictable treatment option with 100% fixture survival and stable bone‐to‐implant contact up to 3 years. The steady state in bone remodelling is indicative of a good long‐term prognosis in non‐smokers but smokers seem to be more prone to bone loss.