Immediate rehabilitation of severely atrophic maxillae using conventional and extended length subcrestal angulated (ELSA) implants: A retrospective analysis of 187 implants in 33 patients with up to three years of function.

PURPOSE: The purpose of this study was to evaluate and determine clinical outcomes and survival rates of straight and extended length subcrestal angulated (ELSA) implants (20-24 mm lengths) placed for immediate (up to 72 h post-operative) or delayed rehabilitation (4 months post-operative) of severely atrophic maxillae. Prosthetic treatment consisted of interim and definitive implant-supported fixed implant-supported prostheses with up to 3 years of function. MATERIALS AND METHODS: A retrospective analysis was conducted of 38 patients (five dropped out; final total was 33), treated between 2017 and 2019 in a private practice. Extended length subcrestal angulated (ELSA) implants and conventional endosseous straight implants (Southern Implants, Irene, South Africa) with (fixed) full arch prostheses were used to restore patients with edentulous maxillae immediately (within 72 hs) or delayed (4 months).  ELSA implants have subcrestal angulations of 24° and 36° of the restorative platforms, external hexagon crestal anti-rotation abutment connections, and lengths between 18 and 26 mm. Implant loading was determined by implant insertion torque values (as determined on the surgical units); 120 Ncm was the threshold level for immediate loading. Clinical and radiographic examinations were done that recorded the clinical outcomes of implants and prostheses. SPSS was used to process the data. RESULTS: Thirty-three patients and 187 implants were included with follow-up periods of at least 12 months (range 12-36 months). The mean age of the study population was 62.6 ± 8.4 years old (at the time of implant placement). Thirty-three patients (86.8%) were followed for 12 months; 13 patients (39.4%) were followed for 24-35 months; 9 patients (27.3%) were followed for 36 months. In total, 13 implants in six patients failed secondary to sinus infections. Mean bone levels (MBLs) were respectively: 0.88 ± 2.12 mm at loading, -1.53 ± 2.03 mm at 12 months, -2.26 ± 1.45 mm at 24 months, and -2.54 ± 1.46 mm at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBL at 36 months than did the conventional implants. One hundred thirty-seven implants were placed and loaded within 72 h; 50 implants were placed and loaded 4 months post placement. The combined implant survival rates were 93.0% at 12 months, 91.1% at 24 months, and 100% at 36 months. The ELSA implants showed significantly lower (p = 0.014) MBLs at 36 months when compared to the conventional implants. CONCLUSIONS: The results of this retrospective clinical chart review indicated that the use of ELSA implants placed into anterior maxillae and nasal crests with accentuated distal tilts (>30°) and simultaneous sinus augmentation provided favorable outcomes for prosthetic rehabilitation in patients with severe atrophic maxillae. ELSA implants placed with simultaneous sinus augmentation are an alternative option to zygomatic implants (ZI) when immediate loading is prescribed. Sinus infections were thought to be the proximate causes of all implant failures. Further long-term clinical studies are warranted with larger patient populations.

Previsibilidade de reabilitações de maxilas edêntulas com a técnica all-on-four: revisão de literatura / Previsibility of edental jaw rehabilitations with the all-on-four technique: literature review

Objetivo: avaliar a previsibilidade das reabilitações de maxilas edêntulas através da técnica all-on-four, mensurada pelas tensões sobre implantes em estudos laboratoriais e sobrevida de próteses, perda óssea marginal e sucesso dos implantes em estudos clínicos. Revisão de literatura: foi executada uma busca na literatura nas bases de dados Lilacs, SciELO e PubMed/Medline, utilizando termos relacionados ao tema, sem restrição temporal e adaptados para cada base. As buscas foram realizadas por um único examinador no período de setembro a novembro de 2019. Após a leitura crítica dos 21 artigos selecionados, constata-se que existem vários estudos com muitos delineamentos que avaliaram a previsibilidade mensurada de várias formas. Considerações finais: diante das evidências científicas encontradas, a reabilitação de maxilas edêntulas com a técnica all-on-four demonstra ser previsível e estável. Estudos retrospectivos, prospectivos e revisões sistemáticas relatam altos índices de sucesso, baixa perda óssea marginal, embasando o uso da técnica all-on-four na odontologia.(AU)

Objective: to assess the predictability of edentulous maxillary rehabilitation using the all-on-four technique, measured by tensions over implants in laboratory studies and prosthetic survival, marginal bone loss and implant success in clinical studies. Literature Review: A literature search was performed in the Lilacs, SciELO and PubMed/ Medline databases, using terms related to the theme, without time restriction and adapted for each base. The searches were carried out by a single examiner from September to November 2019. After a critical reading of the 21 selected articles, it appears that there are several studies with many designs that evaluated the predictability measured in various ways. Final considerations: In view of the scientific evidence found, the rehabilitation of edentulous jaws with the all-on-four technique proves to be predictable and stable. Retrospective, prospective studies and systematic reviews report high success rates, low marginal bone loss, basing the use of the all-on-four technique in dentistry.(AU)

Comparative accuracy of cone-beam CT and conventional multislice computed tomography for real-time navigation in zygomatic implant surgery.

BACKGROUND: Cone-beam computed tomography (CBCT) and conventional multislice CT (MSCT) are both used in zygomatic implant navigation surgery but the superiority of one technique versus the other remains unclear. PURPOSE: This study compared the accuracy of CBCT and MSCT in zygomatic implant navigation surgery by calculating the deviations of implants. MATERIAL AND METHODS: Patients with severely atrophic maxillae were classified into two groups according to the use of CBCT- or MSCT-guided navigation system. The entry and apical distance deviation, and the angle deviation of zygomatic implants were measured on fused operation images. A linear effect model was used for analysis, with statistical significance set at P < .05. RESULTS: A total of 72 zygomatic implants were inserted as planned in 23 patients. The comparison of deviations in CBCT and MSCT groups showed a mean (± SD) entry deviation of 1.69 ± 0.59 mm vs 2.04 ± 0.78 mm (P = .146), apical deviation of 2 ± 0.68 mm vs 2.55 ± 0.85 (P < .001), and angle deviation of 2.32 ± 1.02° vs 3.23 ± 1.21° (P = .038). CONCLUSION: Real-time zygomatic implant navigation surgery with CBCT may result in higher values for accuracy than MSCT.

Zygomatic implants supported rehabilitations in atrophic maxilla: sinus complications, radiological, periodontal and prosthodontic evaluations: a one year follow up retrospective longitudinal study.

The rehabilitation of maxillary bone atrophy represents one of the main challenges of modern oral implantology. The use of zygomatic implants in the prosthetic rehabilitation of the patient affected by severe maxillary bone atrophy is another therapeutic alternative, not exempt from complications. The present study included 19 patients with edentulous maxillae who were treated between 2013 to 2015 with at least two zygomatic implants at the Department of Maxillofacial Surgery, Verona, Italy. The purpose of this retrospective longitudinal study was to evaluate sinus complications and radiological, periodontal and prosthetic evaluations of zygomatic implants technique in severe atrophic. Implant-prosthetic rehabilitation of the upper jaw edentulous severely atrophic using zygomatic implants represents one safe and repeatable technique. In terms of implant survival from our study showed an implant CRS (common reporting standard) of 98.5% and a prosthetic CRS 100% with a mean follow-up period of 19.2 months (range). Both recorded data are superimposed on major reported studies in literature.

Modal analysis of two different types of fixed implant-supported prostheses embedded in edentulous maxillae.

PURPOSE: Modal analysis has been used to monitor and quantify the vibration of each component of a prosthesis at its natural frequency. An understanding of the vibrational characteristics of a prosthesis can guide selection of the appropriate prosthesis configuration to prevent excessive stress. In this study, modal analysis of fixed implant-supported prostheses with 4 or 6 abutments in edentulous maxillae was performed. METHODS: Sixteen patients underwent maxillary dental implant treatment and received screw-fixed implant-supported prostheses (9 patients received 4-abutment prostheses and 7 patients received 6-abutment prostheses) in edentulous maxillae. An impact hammer was used for excitation of the prostheses, and vibration was detected on every crown of the prostheses. The modal parameters were determined in each subject. Furthermore, the modal shapes were compared at each natural frequency. RESULTS: The median natural frequencies of subjects with 4- and 6-abutment prostheses were 697 and 781Hz, respectively. The mean damping ratios did not differ significantly between 4- (8.2±1.7%) and 6-abutment (6.6±1.7%) prostheses (p=0.125). The mean maximum displacements of fixed prostheses were significantly lower for 6-abutment (10.3±3.3µm) than for 4- (20.3±9.1µm) prostheses (p=0.004). The median number of vectors in antiphase was significantly lower for 6- (4) than for 4-abutment prostheses (14) (p=0.001). CONCLUSIONS: The current study demonstrated less adverse vibration in the 6-abutment prostheses than in the 4-abutment prostheses, suggesting that modal analysis can contribute to novel future developments in the designs of dental implant prostheses.

Reconstruction of the severely atrophic edentulous maxillae with calvarial bone grafts.

OBJECTIVES: Treatment of the severely atrophic maxilla with dental implants is challenging due to the insufficient horizontal and vertical bone volume and centripetal resorption pattern of the maxilla. Bone-augmentation procedures are often necessary prior to implant placement. The objective of this study was to assess the suitability of using calvarial bone grafts to enable implant placement in severely atrophic maxillae. MATERIAL AND METHODS: Seventeen patients with severe atrophic edentulous maxillae were reconstructed with autogenous calvarial bone grafts. After a 4-month healing period, the patients received a total of 134 dental implants, which were left to heal in submerged positions for 3 months before prosthetic rehabilitation was performed. Patients were followed clinically and radiographically for an average observation period of 53.94 months. RESULTS: At the intraoral recipient sites, two infections developed, causing partial loss of the respective bone grafts. Implant placement, however, was possible at all sites. No donor-site complications occurred. Two of 134 implants were lost in two patients prior to prosthetic loading. The implant survival rate was 98.51%. The implant success rate was 87.6%, and a mean marginal bone loss of 0.62 mm (SD 0.77 mm) was documented. CONCLUSIONS: Patients with severe bone atrophy of the edentulous maxilla can be successfully reconstructed with calvarial bone grafts and dental implants and show a stable clinical and radiographic situation after a mean observation period of 53 months.

Le Fort 1 osteotomy and calvarial bone grafting for severely resorbed maxillae.

INTRODUCTION: Long standing maxillary edentulism leads to alveolar ridge resorption which prevent implant placement and causes prosthetic malocclusion. The aim of the study was to assess vertical and transversal bone increase following Le Fort 1 osteotomy associated with calvarial bone grafting. MATERIALS AND METHODS: 66 patients who presented severely atrophic maxillae were treated with Le Fort 1 osteotomy with bone grafting from 2003 to 2014. Vertical and transversal bone level was measured preoperatively and 6 months post-operatively to calculate the alveolar ridge augmentation. Follow up ranged from 10 months to 11 years. RESULTS: The mean increase of bone height was 9.3 mm and the mean increase of bone width was 6 mm 417 endosseous implants were placed in the grafted maxilla. Mean endosseous implant length was of 10.7 mm at the first molar site (range: 8-16 mm). A total of 25 implants failed, the overall implant survival rate is of 94%. The definitive prosthetis was fixed in 65% of the patients and removable in 35% of the patients. DISCUSSION: Le Fort 1 osteotomy associated with calvarial bone grafting is the main treatment option able to offer fixed bridge and perfect class 1 occlusion in cases of severe maxillary atrophy.

Long-Term Outcomes of Early Loading of Straumann Implant-Supported Fixed Segmented Bridgeworks in Edentulous Maxillae: A 10-Year Prospective Study.

BACKGROUND: There have been few studies investigating the long-term outcome of early-loaded implants with segmented bridgeworks on fully edentulous maxillae. PURPOSE: To evaluate the long-term predictability of early-loaded Straumann implant-supported fixed segmented bridgeworks in edentulous maxillae. MATERIAL AND METHODS: Ninety-one implants were placed in 12 patients with edentulous maxillae. After a healing period of 6 weeks, the abutments were tightened followed by cementing of fixed full-arch prostheses. The patients were recalled after 1, 3, 5, and 10 years of loading for clinical evaluation. Implant success rate, peri-implant soft tissue condition, technical complications, marginal bone loss and patients' satisfaction was assessed. RESULTS: Eleven of the 12 patients attended the 10-year follow-up. Two implants were lost. The implant success rate was 97.6% at implant level and 81.8% at patient level. The mean marginal bone loss was found to be 0.41 ± 0.55mm, 0.53 ± 0.43mm, 0.68 ± 0.76 mm and 1.01 ± 0.85 mm at the 1, 3, 5, and 10-year follow-up respectively. None of the 11 patients showed a modified plaque index (mPLI) or modified bleeding index (mBI) of 3. Only one patient was found to have pocket probing depth (PPD) exceeding 3 mm. Peri-implantitis was found around one of the implants in a patient after 4 years of loading. The success rate of prostheses was 55.3% at prosthesis level and 27.3% at patient level. The most common technical complication of the prostheses was chipping of the ceramic veneer. Damaged veneers were observed in five patients. Other complications were loss of retention and abutment loosening. CONCLUSION: Early loading of Straumann SLA implants for support of full-arch segmented bridgeworks represents a viable therapy for the fully edentulous maxillae in the long term. High success rate of implants, acceptable peri-implant soft tissue condition and excellent patient satisfaction can be achieved, while technical complications of prostheses are common.

Use of Tilted Implants in Prosthetic Rehabilitation / Uso de Implantes Inclinados en la Rehabilitación Protésica

Biomechanical measurements show that tilted implants, when part of a prosthetic support, avoid the use of distal cantilever units. This study included 20 women (78%) and 12 men (22%), aged over 50 years old (89%), with a total of 156 implants. A delayed occlusal loading protocol was used and the average distal implant length and diameter were 10 mm and 4 mm respectively. Patients were followed up for 2 to 5 years after prosthesis connection. The aims of this study are to analyze the use of tilted implants in prosthetic rehabilitation of maxillae to reduce cantilevers length, and to study the biomechanical implications of implant-bone interface.

Mediciones biomecánicas demuestran que los implantes inclinados, cuando son parte de un soporte de prótesis, evitan el uso de unidades distales en voladizo. Se incluyeron 20 mujeres (78%) y 12 hombres (22%), mayores de 50 años (89%), con un total de 156 implantes. Se utilizó un protocolo de carga oclusal retardada, y la longitud y el diámetro promedios del implante a nivel distal distal, fue de 10 mm y 4 mm, respectivamente. Los pacientes fueron seguidos durante 2 a 5 años después de la conexión de la prótesis. El objetivo de este estudio consiste en analizar el uso de los implantes inclinados en la rehabilitación protésica de maxilares para reducir la longitud de los voladizos, y estudiar las implicaciones biomecánicas de la interfase hueso-implante.

Reabilitação da maxila edêntula com implantes e coroas metalocerâmicas CAD/CAM isoladas implantossuportadas: relato de caso / Rehabilitation of the edentulous maxilla using single-tooth, implant-supported CAD/CAM metalloceramic crowns: case report

A forma mais comum de reabilitação de maxilas totalmente edêntulas com implantes osseointegrados é a prótese total fixa parafusada tipo protocolo de Brånemark, na qual os implantes são esplintados. Este relato de caso clínico apresenta uma forma alternativa para reabilitação de maxilas edêntulas com 14 implantes de conexão cone-morse, pilares retos e coroas totais metalocerâmicas isoladas, com infra-estruturas em titânio, empregando-se a tecnologia CAD/CAM. Neste trabalho foram discutidos aspectos referentes ao planejamento, com ênfase ao planejamento virtual, à necessidade de disponibilidade óssea, às facilidades de higienização, biomecânica (possíveis riscos em manter os implantes isolados), à seleção adequada dos implantes e dos componentes protéticos, aos benefícios do conceito de platform switching, às facilidades de confecção das infra-estruturas em titânio pela tecnologia CAD/CAM, entre outros aspectos. Este tipo de reabilitação maxilar mostrou-se muito eficiente, apresentando como principais vantagens a estética melhorada, a facilidade de higienização, o aspecto emocional muito favorável e a satisfação do paciente.

Oral rehabilitation of completely edentulous maxillary arch has been represented by splinted osseointegrated implants according to classic Brånemark protocols. This case report presents an alternative approach with 14 cone-morse connection type implants, universal abutments, and single ceramic-veneered titanium frameworks using the CAD/CAM technology. All aspects regarding to the virtual treatment planning, bone availability, easiness of cleaning, biomechanics (non-splinted units), adequate implant and prosthetic component selection, the benefits of platform-switching mode, titanium framework fabrication using CAD/CAM technology, among others, are discussed as well. This modality demonstrated efficacy, improved esthetics and hygiene, also with a more favorable emotional aspect and patient satisfaction.