A simplified method to reduce prosthetic misfit for a screw-retained, implant-supported complete denture using a luting technique and laser welding

An important aim of implant-supported prostheses is to achieve a passive fit of the framework with the abutments to limit the amount of stress transfer to the bone-implant interface. An efficient and standardized technique is proposed. A definitive screw-retained, implant-supported complete denture was fabricated for an immediately loaded provisional screw-retained implant-supported complete denture. Precise fit was achieved by the use of industrial titanium components and the passivity, by an intraoral luting sequence and laser welding.     

Retrospective evaluation of the success of oral rehabilitation using the Frialit-2 implant system. Part 1: Influence of topographic and surgical parameters

PURPOSE: This retrospective longitudinal study evaluated the success of implant-prosthetic rehabilitation with the Frialit-2 implant system. MATERIALS AND METHODS: The study was performed with 504 patients, from two treatment centers, who had received a total of 1,554 implants between May 1990 and May 2001. The data of these patients, who received the implants in various regions and for various indications, were analyzed with respect to clinical, topographic, and radiographic parameters. The mean observation period was 6.2 years, with a maximum of 134 months. RESULTS: A survival rate of 94.8% was found for all implants. The implant survival rate of 92.6% in the maxilla remained constant after 68 months of observation. In the mandible, the implant survival rate of 96.7% showed no changes after 76 months. Kaplan-Meier analysis identified jaw, occurrence of postoperative complications, and region as statistically significant factors influencing implant survival. Multivariate Cox regression showed that gender, occurrence of postoperative complications, and jaw were factors that increased the risk of implant loss. Statistically significant correlations were found between the incidence of implant loss and vertical bone loss adjacent to the implant at the time of second-stage surgery. CONCLUSION: Implant survival rate is influenced by implant site, gender, and occurrence of complications. On the whole, the Frialit-2 system proved successful in all areas of indication after long-term observation.     

Implant treatment planning and rehabilitation of the anterior maxilla: Part 1.

Implant-supported restorations have become very popular in the management of the partially or completely edentulous patient. Success depends on attentive treatment planning and coordinated teamwork between the surgeon and the restoring dentist. Implants placed in the anterior maxilla require special attention due to esthetic considerations. This article describes the management of a severely resorbed anterior maxilla using principles of guided bone regeneration followed by implant-supported restorations. This case illustrates some of the problems that can arise during the course of treatment.     

The use of Mitek pins in the mandibular lingual releasing approach to oral and/or oropharyngeal carcinomas: a technical note.

Resection of carcinoma of the oral cavity and oropharynx requires adequate exposure. The purpose of this paper is to demonstrate the approach employed (mandibular lingual releasing approach) for resection of some oral cavity or oropharyngeal carcinomas and to point out the indications, advantages, complications, and refinements of this technique. The technique was carried out on 23 patients with oral cavity or oropharyngeal squamous cell carcinomas. A lingual floor-of-mouth flap was created allowing delivery of the tongue and floor of mouth without lip splitting, mandibulotomy, or mandibulectomy. After resection of the tumour and repair of the defect, the musculature of the floor of the mouth was reattached to the lingual cortex of the mandible using Mitek minianchors. There was adequate exposure in all the patients. Wound margin dehiscence occurred in four patients resulting in an orocervical fistula in three patients. Mandibular osteotomy and subsequent osteosynthesis were avoided. Thus instability and infection of the osteotomy site were avoided. However, additional mandibular osteotomy is feasible.     

Evaluation of intrusive mechanics of the type "segmented arch" on a macerated human skull using the laser reflection technique and holographic interferometry

Twelve different systems of intrusion, based on the principle of the "segmented arch," were evaluated on a macerated human skull. The number of teeth involved in the anterior unit and the location of the application points of intrusive force were considered to be variables. Initial displacements of the anterior teeth after loading were registered by means of the laser reflection technique and double exposure holographic recordings. An attempt was made to define "this" intrusive system, achieving the most genuine intrusion (for definition, see text) without flaring of the teeth. When two central incisors were incorporated in the sectional wire, strong torque forces appeared, especially when the intrusive forces seized more distally. When four or six anterior teeth were pinned in the sectional wire, tooth movement seemed to be under better control. When the six front teeth were incorporated in the sectional wire, the center of resistance (for definition, see text) was located more to the distal side of the canines. It seemed more difficult, however, to define the center of resistance of the four incisors; it was situated approximately distal to the lateral incisors. In some of the intrusive systems, the teeth underwent independent mesial or distal rotations. This was easily observed with the laser measuring techniques used.     

Producing a full-scale model from computed tomographic data with the rapid prototyping technique using the binder jet method: a comparison with the laser lithography method using a dry skull

Rapid prototyping using the binder jet method has recently been established and has already produced excellent results in industrial applications. The authors recently developed a technique for producing a full-scale model from computed tomographic (CT) data with the binder jet method as an approach to overcome the shortcomings of the laser lithography method, which is already widely used in medicine. They conducted a comparative investigation of full-scale models made with both techniques using a dry skull to determine the accuracy of the models. It was clearly demonstrated that the accuracy of the binder jet method was high enough to be used in craniomaxillofacial surgery because it was the same as the laser lithography method. This study employed data from the latest helical volume scan computed tomography device using a multidetector. The study showed that the new rapid prototyping technique was satisfactory in terms of speed, cost, installation environment, and accuracy of models, and that detailed shapes and structures can be reproduced well. Because this technique has many advantages over the laser lithography method, it should play a major role in craniomaxillofacial surgery and in other medical fields in combination with advances in CT devices. Although plaster is a more suitable fixation material when the emphasis is on the reproducibility of detailed structures, the binder jet method using starch is extremely useful for simulating operations and determining implant shapes because it allows for the prompt production of models.     

Immediate functional loading of single-tooth TiO2 grit-blasted implant restoration. A controlled prospective study in a porcine model. Part II: Histology and histomorphometry

Background: Evidently, there is a fast‐moving shift from delayed to immediate implant loading. The hypothesis to be tested was that bone reactions adjacent to single TiO₂‐microthreaded implants exposed to immediate masticatory loading for 10 weeks after placement would modulate osseointegration. Materials and Methods: Cylindrical‐ and tapered‐designed implants (Astra Tech AB, Mölndal, Sweden) replaced first and third mandibular premolars respectively in 12 pigs. The animals were allocated into two groups based on soft and hard diet feeding. Each animal received, at random positions, four different masticatory loading conditions: implant with either (1) a cover screw only, (2) a healing abutment, (3) an implant with a crown without occlusal contact, or (4) an implant with a crown in contact with the antagonistic teeth. Results: Histomorphometry showed that there were no statistically significant differences in bone‐implant contact (BIC), bone mass inside/outside of the threads and soft tissue ingrowth ratio for all the implants at 10 weeks after placement irrespective of masticatory loading condition. Bone loss showed a trend of progressive increase for implants with a healing abutment toward implants with occlusal contact. Conclusions: The results of this study rejected the hypothesis and could be explained by the fact that grit‐blasted acid‐etched implants were already placed in dense bone.     

A new technique for the transcrestal sinus floor elevation and alveolar ridge augmentation with press-fit bone cylinders: a technical note.

BACKGROUND: The minimally invasive sinus floor elevation as first described by Summers is limited in the volume of augmentation that is possible. In contrast, the more invasive approach is the sinuslift of Tatum which is indicated for greater bone deficiencies. Therefore, a new technique was developed for transcrestal elevation of the sinus floor and alveolar ridge augmentation with bone dowels in press-fit technique. MATERIALS & METHODS: The crestal cortical bone is cut with a hollow grinder followed by an indirect sinus floor elevation with a plunger. The cylindrical defect is then filled with a cylindrical bone transplant with the press-fit technique. RESULTS: The method was tested in ten fresh porcine skulls and was successful when applied subsequently in two fresh human cadavers (both female, age 60 and 92 years). This was followed by the insertion of another cylinder in overlapping mosaic manner with the dowel-lift technique in the left maxilla in one cadaver. A sinoscopy of the second cadaver experiment showed no perforation of the maxillary sinus membrane. The result was convincing. CONCLUSION: A new method for transcrestal elevation of the maxillary sinus floor and alveolar ridge augmentation with bone cylinders in press-fit technique was developed. The operation combines the minimally invasive approach of Summers with a large augmentation volume otherwise requiring the direct technique of Tatum. These results should encourage further preclinical experiments.     

Candida-associated denture stomatitis. Aetiology and management: A review: Part1. Factors influencing distribution of candida species in the oral cavity

Candida species are yeasts and within the oral cavity, Candida albicans is the most frequently isolated. There is clear evidence that C. albicans adheres to oral surfaces including acrylic dentures and mucosa. The mechanisms of attachment differ, with candidal adhesion to inert surfaces under the control of hydrophobic and electrostatic forces and adhesion to mucosa dependent on a number of complex ligand-recognition systems. Other factors within the oral environment such as saliva, pH, bacteria and hyphal formation have been shown to influence adhesion of candida species to surfaces in the mouth.     

Warty dyskeratoma. A note concerning its occurrence on the oral mucosa, and its possible pathogenesis.

A case of warty dyskeratoma occurring in the oral mucosa is presented. Indirect immunofluorescence tests using the patient's serum showed the presence of IgG class antibodies reactive with intercellular material of guinea-pig lip mucosa and IgM class antinuclear antibodies. The patient did not have any clinical histopathological, haematological or serological evidence of other autoimmune disease.     

World Workshop on Oral Medicine VII: Targeting the microbiome for oral medicine specialists—Part 1. A methodological guide

Advances in high‐throughput sequencing technologies have allowed for a rapid increase in knowledge about the human microbiome in both healthy and diseased states, which is expected to increase our understanding of multifactorial diseases. The World Workshop on Oral Medicine VII chose the microbiome as one of its topics of focus. Part 1 of this review provides updated knowledge in the field of microbiome research, describes the advantages and disadvantages of currently available sequencing technologies, and proposes a seven‐step “recipe” for designing and performing studies that is supported by contemporary evidence. Part 2 of this review in a companion paper discusses the results of high‐throughput sequencing studies published to date on the microbiota associated with oral mucosal diseases. The goal of this collective enterprise is to encourage more oral medicine specialists to become engaged in multidisciplinary collaborations to investigate the role of the microbiome in relation to oral diseases, which could potentially lead to enhanced diagnosis, risk assessment and treatment of these patients.     

A randomized clinical trial comparing the efficacy of mandibular implant-supported overdentures and conventional dentures in diabetic patients. Part V: food preference comparisons.

STATEMENT OF PROBLEM: The functional benefits of replacing old dentures with new conventional mandibular dentures or implant-supported overdentures has not been fully determined. PURPOSE: This study assessed the impact of these 2 types of replacement dentures on the food choices of diabetic patients. MATERIAL AND METHODS: A total of 68 diabetic patients with original complete dentures participated in this study. Diabetes was controlled with insulin in 38 patients (IT) and without insulin in 30 patients (NIT). All subjects received conventional maxillary dentures; 25 received mandibular conventional dentures (CD), and 43 received overdentures with plastic clips and a Hader bar attached to 2 osseointegrated implants (IOD). Subjects rated their perceptions of taste acceptability, texture acceptability, and chewing ease on a 4-point nominal scale and eating frequency on a 5-point scale for 13 specific foods at baseline (with original dentures) and at 6 months post-treatment completion (PTC). Fisher exact tests were used to compare the change in percentage distributions of responses with treatment. A 2 x 2 x 2 repeated-measures analysis of variance (ANOVA) was performed to compare mean scores between the 2 denture groups, 2 diabetic groups, and 2 time intervals for each of the 13 foods and 4 questions related to food acceptability. RESULTS: At baseline, no significant differences were found between the frequency distributions of responses in the CD and IOD groups or the IT and NIT groups for all 52 comparisons. With both types of study dentures, a higher percentage of patients perceived deterioration rather than improvement in function. When percentage distributions based on actual positive or negative change (treatment effect) in patient responses were compared, significant differences were found for 3 of the 52 responses, in favor of the IOD group. ANOVA demonstrated significant mean differences for 4 of the 52 comparisons. CONCLUSION: Both types of study dentures resulted in declines in the perceived taste and texture acceptability of almost all test foods. Declines in perceived chewing ease and eating frequency were more common and greater in the CD than in the IOD group. Both types of study dentures failed to affect food choices, as evidenced by declines or limited improvement in the perceived frequency with which most foods were eaten.     

Immediate occlusal loading and tilted implants for the rehabilitation of the atrophic edentulous maxilla: 1-year interim results of a multicenter prospective study

OBJECTIVES: The aims of this prospective study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants for the rehabilitation of fully edentulous maxillae and to compare the outcome of axial vs. tilted implants. MATERIAL AND METHODS: Forty-one patients with edentulous maxillae were included in the study. Each patient received a full-arch fixed bridge supported by four axial implants and two distal tilted implants. Loading was applied within 48 h from surgery. Patients were scheduled for follow-up at 6 months, 1 year and annually up to 5 years. Radiographic evaluation of marginal bone-level change was performed at 1 year. RESULTS: One patient died 4 months after surgery. Thirty patients were followed for a minimum of 1 year (range 3-42 months, mean 22.1 months). Three failures were recorded at 1-year follow-up (two axial implants and one tilted). Two more implants (one tilted and one axially placed) were lost within 18 months of loading. The 1-year implant survival rate was 98.8% for both axial and tilted implants. Prosthesis success rate was 100% at 1 year. Marginal bone loss around axial and tilted implants at 12-month evaluation was similar, being, respectively, 0.9+/-0.4 (standard deviation) mm and 0.8+/-0.5 mm. CONCLUSIONS: The present preliminary data suggest that immediate loading associated with tilted implants could be considered to be a viable treatment modality for the atrophic maxilla and that there does not seem to be a different clinical outcome between tilted and axial implants.     

Digital simulations on unequally spaced grids.: Part 1. Critical remarks on using the point method by discretisation on a transformed grid

The paper demonstrates that the variable transformation variant of the point method (point 2 methods throughout the paper) suffers from serious problems, which prevent efficient simulations of electrochemical kinetic–diffusion systems. It will be shown that the limitation of the applicability of this method to very slowly expanding grids and small values of the grid parameter a does not result from the nature of the diffusion problem. It is simply a consequence of inaccuracies introduced by discretizing equations resulting from a variable transformation which hold true only if the limiting process ΔY→0 is really executed. Such problems can be avoided by an alternative implementation of the point method (point 1 method throughout the paper) based on discretizing the second-order space derivative directly on the expanding grid using unequal intervals. This method is only first-order accurate but works much better than the variable transformation variant. It gives fairly accurate results on moderately expanding grids (ΔY≤0.25) no matter how large the parameter a is. However, due to the reduced precision of both methods neither of the two is able to compete with more accurate techniques such as the finite element or box method.     

A prosthodontic technique to improve the simplicity and the efficacy of angled abutments for divergent implant situations: a technical note

Esthetic demands and nonparallel situations between the axial direction of the suprastructure and the implant require angulation of the abutment. The Conical Seal design avoids microleakage and micromovements after the abutment has been seated and finally retained via screw. However, there is no protection against rotation during the fixation procedure. Therefore, a control device and/or method for a reproduction of correct seating during each treatment step of permanent prosthesis fabrication is desirable. The purpose of this investigation was to develop a device to ensure the correct seating by less expensive, safer, easier, and more precise methods. The sequence of components and the standard procedure required modification: in the modified procedure, the impression is made at the implant level, and the straight implant replica is embedded in the laboratory cast. The angled abutment needs modification by grinding to create small margins in the mesial, distal, and palatal walls. Three materials that are used in daily dental practice are combined to fabricate an individual transfer device. Direct waxup of the restoration onto the angled abutment without a prefabricated component shortens the laboratory processing. The modified sequence and procedure, small alterations of the angled abutment, and an individual transfer device can simplify the transfer procedures, improve clinical performance and applicability, and shorten chair time.