Carlos Eduardo Francischone

“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.

The influence of surface treatment on the implant roughness pattern

An important parameter for the clinical success of dental implants is the formation of direct contact between the implant and surrounding bone, whose quality is directly influenced by the implant surface roughness. A screw-shaped design and a surface with an average roughness of Sa of 1-2 µm showed a better result. The combination of blasting and etching has been a commonly used surface treatment technique. The versatility of this type of treatment allows for a wide variation in the procedures in order to obtain the desired roughness. Objectives To compare the roughness values and morphological characteristics of 04 brands of implants, using the same type of surface treatment. In addition, to compare the results among brands, in order to assess whether the type of treatment determines the values and the characteristics of implant surface roughness. Material and methods Three implants were purchased directly from each selected company in the market, i.e., 03 Brazilian companies (Biomet 3i of Brazil, Neodent and Titaniumfix) and 01 Korean company (Oneplant). The quantitative or numerical characterization of the roughness was performed using an interferometer. The qualitative analysis of the surface topography obtained with the treatment was analyzed using scanning electron microscopy images. Results The evaluated implants showed a significant variation in roughness values: Sa for Oneplant was 1.01 µm; Titaniumfix reached 0.90 µm; implants from Neodent 0.67 µm, and Biomet 3i of Brazil 0.53 µm. Moreover, the SEM images showed very different patterns for the surfaces examined. Conclusions The surface treatment alone is not able to determine the roughness values and characteristics.

A Retrospective Evaluation of the Survival Rates of Splinted and Non-Splinted Short Dental Implants in Posterior Partially Edentulous Jaws

BACKGROUND The aim of the present study is to evaluate the survival rate and bone loss around short implants (≤10 mm) supporting splinted or non-splinted posterior prostheses during a follow-up period of 3 to 16 years. METHODS A total of 453 implants from 198 patients was divided into splinted or non-splinted groups. Implant survival rate was calculated for each group, and potential risk was represented as odds ratio (OR). The final linear distance from implant platform level to the first bone-to-implant contact was compared to this same reference just after loading by digital periapical radiographs to determine the marginal bone loss (BL). RESULTS The splinted group comprised 219 implants in 86 patients, whereas the non-splinted group included 234 implants from 112 patients. The mean follow-up period was 9.7 ± 3.7 years. Although different success rates were found for splinted (97.7%) and non-splinted (93.2%) groups, they exhibited similar BL (1.22 ± 0.95 mm and 1.27 ± 1.15 mm, respectively). The success of splinted implants was associated with no other variable, whereas non-splinted implants exhibited higher risk of failure when placed in men (OR = 3.2) and when implants shorter than 10 mm were used (OR = 3.6 and 4.1 for 8.5 mm and 7 mm, respectively). Regardless of group, 71.4% of the unsuccessful implants failed before the end of the first year after loading. CONCLUSION Non-splinted posterior short implants had a somewhat lower success rate than splinted short implants, and the failure rate in non-splinted short implants appeared to be greater in males as well as in implants ≤10 mm.

Clinical accuracy of flapless computer-guided surgery for implant placement in edentulous arches.

PURPOSE Although flapless computer-guided implant placement provides important benefits, deviations from the planned implant placement in the edentulous arch may pose significant risks. This study evaluated the reliability and accuracy of a flapless computer-guided surgical approach. MATERIALS AND METHODS Computer-generated preoperative implant planning was compared to actual placement by cone-beam computerized tomography (CBCT) scanning of patients before and after surgery. A well-fitting complete denture or optimized prosthetic tooth arrangement was used and converted to a radiographic template. Prior to scanning, esthetics and functional aspects were checked clinically. The implant positions were virtually determined by the implant planning software relative to the bone structure and prospective tooth position. After implant placement, new CBCT scans were obtained for each subject. Software was used to fuse the images of the planned and placed implants, and the locations and axes were compared. The normality of the data distribution was evaluated by the Kolmogorov-Smirnov test. Mean values were compared between groups based on the upper or lower jaws with the t test for independent samples. The level of significance was fixed at 5%. RESULTS Sixty-two implants were placed in edentulous arches with stereolithographic surgical guides in 14 patients. Damage due to implant placement was not observed in any critical anatomical structure. Compared to the planned implants, placed implants showed mean and standard deviation linear measurements at the cervical, middle, and apical implant portions of 2.17 (± 0.87), 2.32 (± 1.52), and 2.86 (± 2.17) mm, for the maxilla, and 1.42 (± 0.76), 1.42 (± 0.76), and 1.42 (± 0.76) mm, for the mandible, respectively. The angular deviations were 1.93 (± 0.17) and 1.85 (± 0.75) degrees for the maxilla and mandible, respectively. The linear deviation differed significantlybetween the upper and lower jaws, but the angular deviation did not. CONCLUSION Flapless computer-guided surgery may be a viable treatment option for rehabilitating the edentulous arch.

Clinical evaluation of ceramic inlays and onlays fabricated with two systems: five-year follow-up.

This study evaluated the five-year clinical performance of ceramic inlays and onlays made with two systems: sintered Duceram (Dentsply-Degussa) and pressable IPS Empress (Ivoclar Vivadent). Eighty-six restorations were placed by a single operator in 35 patients with a median age of 33 years. The restorations were cemented with dual-cured resin cement (Variolink II, Ivoclar Vivadent) and Syntac Classic adhesive under rubber dam. The evaluations were conducted by two independent investigators at baseline, and at one, two, three, and five years using the modified United States Public Health Service (USPHS) criteria. At the five-year recall, 26 patients were evaluated (74.28%), totalling 62 (72.09%) restorations. Four IPS restorations were fractured, two restorations presented secondary caries (one from IPS and one from Duceram), and two restorations showed unacceptable defects at the restoration margin and needed replacement (one restoration from each ceramic system). A general success rate of 87% was recorded. The Fisher exact test revealed no significant difference between Duceram and IPS Empress ceramic systems for all aspects evaluated at different recall appointments (p>0.05). The McNemar chi-square test showed significant differences in relation to marginal discoloration, marginal integrity, and surface texture between the baseline and five-year recall for both systems (p<0.001), with an increased percentage of Bravo scores. However, few Charlie or Delta scores were attributed to these restorations. In conclusion, these two types of ceramic materials demonstrated acceptable clinical performance after five years.

Micrometric characterization of the implant surfaces from the five largest companies in Brazil, the second largest worldwide implant market

PURPOSE To characterize the surface of implants from Brazilian companies by light interferometry and evaluate the level of control of the surface treatment process. MATERIALS AND METHODS Oral implants from the five largest Brazilian companies were evaluated topographically. The surfaces of the implants were analyzed on the tops, valleys, and flanks of the threads, totaling nine measurements for each unit. The implants and results were separated in groups by their types of surface treatment and compared with well known international implants used as references. RESULTS The implants examined presented a mean height deviation of less than 1 μm, which was considered minimally rough, except for the SIN-SW implant (1.01 μm) and the Vulcano Actives design (1.26 μm). The surface enlargement values varied considerably in relation to the reference implant, with lower values noted in the group of implants subjected to sandblasting and acid-etching and with higher values obtained in the group treated by acid-etching and anodizing. There were statistically significant differences between batches of implants from all companies assessed, indicative of a substantial variance in implant topography from one batch to another. CONCLUSIONS The low values of roughness found in the measurements and the differences between the values of the batches suggest that these companies should consider improving their surface treatments to achieve more uniform roughness.

Cross-splinting a weakened tooth with a horizontal pin: A new method

This study determined that the attachment of composite to unetched enamel had no significant effect on the bond strength of composite to the same enamel surface after etching. Half of the teeth were prepared (0.5 mm enamel reduction) to simulate the clinical indirect veneer technique, and the others were unprepared. Composite interim restorations were attached (without etching) to half of both groups of teeth. When composite restorations were subsequently attached by acid etching and debonded, there were no significant differences in bond strengths among the four groups. Consequently, the technique of composite attachment to enamel before etching may be used by dentists without fear of affecting the bond strength of composite to that same enamel after etching.

Esthetic outcomes and tissue stability of implant placement in compromised sockets following immediate dentoalveolar restoration: results of a prospective case series at 58 months follow-up.

The aim of this prospective case series was to evaluate the stability of esthetic treatment after single tooth replacement in compromised sockets using the immediate dentoalveolar restoration (IDR) concept. Eighteen patients underwent immediate implant placement and IDR of bone defects. Clinical photographs were used to evaluate the gingival contour and papillae. The mean soft tissue dimensions at baseline and final follow-up were 12.85 ± 2.33 mm and 12.79 ± 2.48 mm, respectively, revealing no recession. The mean mesial and distal papillary heights increased slightly over time. Stable periimplant soft tissues and satisfactory esthetic outcomes were achieved.

Clinical evaluation of two types of ceramic inlays and onlays after 6 months

The aim of the present study was to evaluate the clinical performance of two types of ceramics: a slurry-powder ceramic (Duceram Plus, Degussa) - D and a hot-pressed leucite-based glass-ceramic (IPS Empress, Ivoclar Vivadent) - IPS. Eighty-six restorations, 44 IPS and 42 D, were made by one operator. A total of 33 onlays and 53 inlays on twenty-seven premolars and 59 molars were cemented in 35 patients of both sexes, mean age 35 years. All restorations were cemented with the dual-resin cement (Variolink, Ivoclar-Vivadent) under rubber dam and were evaluated at the baseline and after six months, using the modified U.S.P.H.S. criteria for postoperative sensitivity, secondary caries, fracture, color match, marginal discoloration, marginal integrity and surface texture. Additionally radiographs and intraoral photographs were carried out. At baseline 86 restorations were analyzed and all of them received Alfa rating, except for the following that received Bravo rating for postoperative sensitivity - IPS (2.27%); D (7.14%); for color match - IPS (2.27%); D (2.38%) and for surface texture - IPS (2.27%); D (11.90%). After 6 months 100% of the restorations were analyzed and the following received Bravo rating: color match - IPS (4.55%) and D (9.52%); surface texture - IPS (2.27%) and D (11.9%); marginal discoloration - IPS (6.82%) and D (4.76%) and marginal integrity - IPS (4.55%) and D (7.14%). The results were submitted to the Fisher and McNemar Statistical Tests. No significant differences were noticed between the two ceramics. Both ceramics demonstrated satisfactory clinical performance after six months.

Fracture Strength of Implant-Supported Ceramic Crowns with Customized Zirconia Abutments: Screw Retained vs. Cement Retained

PURPOSE To compare the fracture resistance before and after cyclic fatigue assays of ceramic crowns with customized zirconia abutments when screw retained and cemented onto implants. MATERIALS AND METHODS The sample of this study consisted of 40 ceramic crowns with zirconia infrastructure fixed onto external hexagonal implants. The crowns were distributed into two groups (n = 20): Screw-retained and cemented crowns. Half the crowns of each group (n = 10) underwent compression until fracture and the other half (n = 10) underwent cyclic fatigue and subsequent compression until fracture. The cyclic fatigue test was carried out using an electromechanical fatigue device (loads from 0 to 100 N, 2 Hz frequency, in distilled water, at 37 °C for a period of 1 million cycles). The compression test was carried out using a universal testing machine with a 0.5 mm/min speed and 5 KN load cell. After fracture, the crowns were classified according to the type of fracture. Students t test (p < 0.05) was used for statistical analysis. RESULTS The cyclic fatigue altered neither the mean fracture resistance of the screw-retained crowns (before = 1068.31 N, after = 891.49 N; p > 0.05) nor that of the cemented crowns (before = 2117.78 N; after = 2094.81 N; p > 0.05); however, the mean fracture resistance of the cemented crowns was higher than that of the screw-retained crowns both before (p < 0.001) and after (p < 0.001) the cyclic fatigue. Fractures occurred most frequently in the ceramic veneer, followed by fracture of some of the copings. CONCLUSION The ceramic crowns cemented onto the customized zirconia abutments offered greater fracture resistance than ceramic crowns with customized zirconia abutments screw retained onto implants. The cyclic fatigue did not seem to influence the fracture resistance of these crowns, whether cemented or screw retained onto implants. Fracture of the veneering ceramic was the predominant failure in this study.