Clinical outcomes in the presence and absence of keratinized mucosa in mandibular guided implant surgeries: a pilot study with a proposal for the modification of the technique.

OBJECTIVE: To test the hypothesis of the outcome of complete arch flapless guided implant surgery mandibular rehabilitations in the presence or absence of a residual band of keratinized mucosa (KM) < 6 mm wide in the vestibular-lingual aspect, with and without a modification of the surgical protocol. METHOD AND MATERIALS: Thirty-nine patients were included in this study (12 men and 27 women), with a mean age of 62.5 years (range, 42 to 79 years), divided into 3 groups of 13 patients according to the status of residual band of KM: group 1, KM < 6 mm rehabilitated through a modified guided surgical protocol with flap opening to preserve KM; group 2, KM ≥ 6 mm; and group 3, KM < 6 mm; patients from both groups 2 and 3 were rehabilitated through flapless guided implant surgery without modification of the protocol. Group 2 and 3 patients were age- and sex-matched with group 1. Outcome measures were clinical attachment loss (CAL) ≥ 2 mm after 1 year (backward conditional regression), incidence of dehiscences, dental plaque, bleeding, and implant infections. The level of significance chosen was 5%. RESULTS: Thirty-nine patients with 156 implants were followed for 1 year, and no dropouts occurred. Absence of a residual band of KM ≥ 6 mm in the vestibular-lingual aspect was significantly associated with CAL (odds ratio, 39.1; P = .036) and dehiscences (P = .003). CONCLUSION: Within the limitations of this study, the absence of a residual band of KM ≥ 6 mm wide in the vestibular-lingual aspect in patients rehabilitated in the complete edentulous mandible with flapless guided implant surgery may be associated with CAL and a higher incidence of dehiscences after 1 year of follow-up. This possible association needs to be confirmed in studies with stronger designs and longer follow-ups.

Three-year outcome of a retrospective cohort study on the rehabilitation of completely edentulous atrophic maxillae with immediately loaded extra-maxillary zygomatic implants.

AIM: To report retrospectively on the 3-year follow-up results in the rehabilitation of completely edentulous atrophied maxillae using extra-maxillary zygomatic implants. MATERIALS AND METHODS: This retrospective report includes an initial cohort of 39 patients (30 women and 9 men), with a mean age of 53 years, which were followed up for 3 years. The patients were rehabilitated with 39 fixed prostheses and 169 implants (92 zygomatic and 77 regular implants). Final abutments were delivered at surgery stage and a provisional fixed dental prosthesis was manufactured and attached to the implants on the same day as surgery, achieving immediate function. Outcome measures were prosthesis success, implant success, complications, probing pocket depths (PPDs) and marginal bone levels (only for conventional implants). Data were analysed with descriptive and inferential analyses. RESULTS: Five patients dropped out of the study and 1 patient died after 30 months of follow-up due to causes unrelated to the oral rehabilitation. No prosthesis or implant was lost, though 1 implant presented mobility at the 1-year follow-up but remained stable on subsequent follow-ups. Six complications occurred (18%): 5 cases of sinusitis in 5 patients preoperatively diagnosed with sinusitis and whose sinus membrane was disrupted during surgery, and 1 oro-antral communication. Median PPD values were 3 mm in all follow-up appointments (2, 4 and 6 months, 1, 2 and 3 years), comparable to the values of probing depths assessed for standard implants. CONCLUSIONS: Within the limitations of this study, the medium-term outcome (3 years) indicates that severely atrophied completely edentulous maxilla rehabilitations supported by immediately loaded zygomatic implants are viable.

"All-on-4" immediate-function concept for completely edentulous maxillae: a clinical report on the medium (3 years) and long-term (5 years) outcomes.

BACKGROUND: Immediate implant function has become an accepted treatment modality for fixed restorations in totally edentulous mandibles, whereas experience from immediate function in the edentulous maxilla is limited. PURPOSE: The purpose of this study was to report on the medium- and long-term outcomes of a protocol for immediate function of four implants (All-on-4, Nobel Biocare AB, Göteborg, Sweden) supporting a fixed prosthesis in the completely edentulous maxilla. MATERIALS AND METHODS: This retrospective clinical study included 242 patients with 968 immediately loaded implants (Brånemark System TiUnite, Nobelspeedy, Nobel Biocare AB) supporting fixed complete-arch maxillary all-acrylic prostheses. A specially designed surgical guide was used to facilitate implant positioning and tilting of the posterior implants to achieve good bone anchorage and large interimplant distance for good prosthetic support. Follow-up examinations were performed at 6 months, 1 year, and thereafter every 6 months. Radiographic assessment of the marginal bone level was performed after 3 and 5 years in function. Survival was estimated at patient level and implant level using the Kaplan-Meier product limit estimation with 95% confidence intervals. RESULTS: Nineteen immediately loaded implants were lost in seventeen patients, giving a 5-year survival rate estimation of 93% and 98% at patient and implant level, respectively. The survival rate of the prosthesis was 100%. The marginal bone level was, on average, 1.52 mm (standard deviation [SD] 0.3 mm) and 1.95 mm (SD 0.4 mm) from the implant/abutment junction after 3 and 5 years, respectively. CONCLUSION: The high survival rates at patient and implant level indicates that the immediate-function concept for completely edentulous maxillae using the present protocol is viable in the medium- and long-term outcomes.

Uso da prototipagem para o planejamento de reabilitações maxilares em carga imediata: relato de caso / Use of the prototype to planning rehabilitation atrophic maxillary in immediate load sistem: a case report

A prototipagem é um recurso valioso para auxílio no diagnóstico e planejamento do posicionamento das fixações. Para demonstrar a importância de um adequado planejamento cirúrgico e protético visando sucesso elongevidade dos implantes, iremos explanar na forma de um caso clínico a função da prototipagem nos procedimentos cirúrgico-protéticos em sistema de carga imediata em maxila atrófica.

Zygomatic bone: anatomic bases for osseointegrated implant anchorage.

PURPOSE: The aim of the present study was to evaluate zygomatic bone thickness considering a possible relationship between this parameter and cephalic index (CI) for better use of CI in the implant placement technique. MATERIALS AND METHODS: CI was calculated for 60 dry Brazilian skulls. The zygomatic bones of the skulls were divided into 13 standardized sections for measurement. Bilateral measurements of zygomatic bone thickness were made on dry skulls. RESULTS: Sections 5, 6, 8, and 9 were appropriate for implant anchorage in terms of location. The mean thicknesses of these sections were 6.05 mm for section 5, 3.15 mm for section 6, 6.13 mm for section 8, and 4.75 mm for section 9. In only 1 section, section 8, did mean thickness on 1 side of of the skull differ significantly from mean thickness on the other side (P <.001). DISCUSSION: For the relationship between quadrant thickness and CI, sections 6 and 8 varied independently of CI. Section 5 associated with brachycephaly, and section 9 associated with subbrachycephaly, presented variations in the corresponding thickness. CONCLUSION: Based on the results, implants should be placed in sections 5 and 8, since they presented the greatest thickness, except in brachycephalic subjects, where thickness was greatest in section 5, and in subbrachycephalic subjects, where thickness was greatest in section 9. CI did not prove to be an appropriate parameter for evaluating zygomatic bone thickness for this sampling. (More than 50 references.)