Patient satisfaction survey of mandibular two-implant–retained overdentures in a predoctoral program

Additively manufactured CAD-CAM complete dentures with intraoral scanning and cast digitization: A controlled clinical trial

PURPOSE

To assess, clinically, patient satisfaction of additively manufactured complete dentures with intraoral scanning and hybrid cast digitization in comparison with conventional complete dentures.

MATERIALS AND METHODS

Participants who were edentulous in both arches were recruited and received three types of complete dentures (CDs): conventionally manufactured with conventional impression (CC), additively manufactured with intraoral scanning (AMI), and additively manufactured with cast digitization (AMH). Definitive impressions of the edentulous arches were made with medium viscosity polyvinyl siloxane (Hydrorise Monophase; Zhermack, Italy) for the CC group, intraoral scanning (TRIOS 4; 3Shape, Copenhagen, Denmark) for the AMI group, and laboratory scanning of the definitive casts (Ceramill Map400 AMANNGIRRBACH, Pforzheim, Deutschland) for the AMH group. The trial dentures of the CC group were scanned for occlusion registrations of the AMI and AMH groups and were used to guide the designing process (Exocad 3.0 Galway; Exocad GmbH). The AMI and AMH dentures were additively manufactured with a vat-polymerization 3D printer (Sonic XL 4K; phrozen, Taiwan). Patient satisfaction and clinical outcome were assessed with OHIP EDENT, and 14-factor criteria, respectively. Statistical analyses were performed with paired sample t-test and one-way repeated measure ANOVA for satisfaction, Wilcoxon signed rank test for clinical outcome, and Pearson's r (r) for effect size, with α = 0.05.

RESULTS

A total of 20 participants were included. Satisfaction had no statistically significant difference within or among the groups (p < 0.105). Within-group comparison between the two arches showed no statistical significance for the clinical outcome except for a significantly higher maxillary AMI score (p = 0.01, r = -0.40 with medium effect size). For among group's comparison; AMI had a significantly lower score than CC for the maxillary and mandibular arches (p = 0.01, r = -0.40, medium effect size, and p = 0.003, r = -0.47, medium effect size), and significantly lower score than the mandibular AMH (p = 0.03, r = -0.47, medium effect size), with significantly lower quality in teeth arrangement and retention domains for the AMI, and teeth arrangement for the AMH, in comparison with CC.

CONCLUSIONS

Patient satisfaction with both types of additively manufactured dentures is comparable to conventional dentures. The comparable overall clinical outcomes between hybrid and conventional dentures indicate that additive manufacturing is an acceptable clinical substitute for the conventional methods. However, additively manufactured dentures made with intraoral scanning have lower clinical quality and retention than hybrid and conventional dentures, particularly for the mandibular arch. Teeth arrangement of both additively manufactured dentures is clinically inferior to the conventional denture.

Immediate, non-submerged, three-dimensionally printed, one-piece mandibular molar porous root-analogue titanium implants: A 2-year prospective study involving 18 patients

This study prospectively evaluated non-submerged, three-dimensionally printed, one-piece molar porous root-analogue titanium implants. A total of 18 non-restorable multiple-rooted teeth in 18 patients, aged 22-64 years, were included in this study. A series of computed tomography images of the mandible were selected and rendered into a digital model. The non-restorable mandibular molars were digitally separated from the surrounding alveolar bone, and served as the template on which the porous root-analogue titanium implants (RAIs) were designed with computer-aided design (CAD) software. The porous molar RAIs were fabricated with the selective laser melting technique (average particle size 20 μm) and inserted into the alveolar sockets after extraction of the non-restorable molars. Definitive restorations were placed after 3 months of uninterrupted healing. Peri-implant clinical and radiographic measurements were obtained 2 years later. All patients functioned well following 2 years of functional loading, and peri-implant clinical and radiographic measurements demonstrated implant stability. No implants were lost at the 2-year follow-up, and the survival rate was 100%. Three-dimensionally printed one-piece molar porous RAIs may be a promising option for the replacement of non-restorable molars that are planned for extraction. Additional studies are required to evaluate the long-term survival of implants fabricated using this technique.

Fabrication of dental implants by the additive manufacturing method: A systematic review

STATEMENT OF PROBLEM

Placement of dental implants depends, among other factors, on anatomic conditions such as sufficient bone height and thickness. Thus, individualized dental implants seem to offer benefits for patients with alveolar bone resorption. Additive manufacturing has allowed for the fabrication of custom implants with microscale resolution and, although the efficiency of the process is unclear, is a potential process for manufacturing dental implants.

PURPOSE

The purpose of this systematic review was to evaluate the current situation of additive manufacturing techniques for fabricating dental implants.

MATERIAL AND METHODS

An electronic search was performed in the databases PubMed, Lilacs, Cochrane Library, and Science Direct, with the terms "additive manufacturing" AND "dental implants," "rapid prototyping" AND "dental implants," "3 D printing" AND "dental implants," "electron beam melting" AND "dental implants," "selective laser melting" AND "dental implants." The articles were screened, and the final selection of articles was obtained by using the inclusion and exclusion criteria.

RESULTS

The database search resulted in 1322 articles, which were screened for title and/or summary according to the inclusion criteria. From the selected 38 articles, 30 remained after applying the exclusion criteria. These were read completely, resulting in a selection of 13 articles for this systematic review. Owing to the great variety of articles with different objectives, the results were based on a descriptive analysis of the following topics: additive manufacturing technique and material, printed structure and implant design, implant characteristics, mechanical analysis, surface treatment, and osseointegration.

CONCLUSIONS

Additive manufacturing is a new technology that may solve many problems in diverse fields. In dentistry, however, further studies are needed to improve the method for manufacturing custom dental implants because no standard methodology is available. Moreover, the advantages and disadvantages of the process are not yet clearly defined.

Implant-supported overdentures with different clinical configurations: Mechanical resistance using a numerical approach

STATEMENT OF PROBLEM

Implant-supported overdentures (IODs) are a treatment option for patients with complete edentulism. However, this treatment increases the possibilities of peri-implant complications, characterized by inflammation or partial loss of surrounding hard and soft tissues.

PURPOSE

The purpose of this finite element analysis study was to evaluate the mechanical performance of different bar-IOD designs under different clinical configurations by comparing the stress and strain distribution on the bone during secondary stabilization.

MATERIAL AND METHODS

A finite element model of the mandible representing a patient with complete edentulism was developed. Different designs of bar-IODs were modeled and compared. The parameters studied were the material properties (cobalt-chromium, zirconium dioxide, titanium grade 5, and titanium grade 4), diameter and bar-IOD cross-sectional shape, tilt of the posterior implants (30 degrees), presence of a distal extension cantilever in the bar-IODs (12 mm), and number of implants (4 or 6). Two different mastication loading conditions were analyzed. One- and 2-way ANOVAs and the Tukey honestly significant differences post hoc test (α=.05) were used to determine the significant von Mises stress and strain values in the bone.

RESULTS

The 4 materials tested in the bar-IOD did not have a significant mechanical effect on the bone (P<.05). A smaller diameter and structure of the bar-IOD led to significantly higher bone stress (P<.001). A distal extension cantilever led to an increased stress concentration (model M1 versus model M3: P<.001), which reached 50% in the event of tilting of the posterior implants (model M2 versus model M4: P<.001). Tilting of the posterior implants alone, without extension, had a nonsignificant effect (model M3 versus model M4: P=.999). Model M5 supported with 6 implants reduces the stress transferred to the bone compared with model M3 supported with 4 implants (P<.05).

CONCLUSIONS

Distal extensions in bar-IODs, the tilt of the posterior implants, and the low amount of material in the cross-sectional area in the bar-IOD were the most influential parameters on the mechanical resistance of dental implants in the mandibular bone.

Electromyography evaluation of masseter and temporalis, bite force, and quality of life in elderly patients during the adaptation of mandibular implant-supported overdentures

OBJECTIVES

The aim of this study was to investigate the outcomes of the installation of two implant-supported overdentures until such treatment is complete. Although this treatment is well established in the literature, there are no studies comparing what happens to muscles and the quality of life (QoL) of patients during the treatment.

METHODS

We selected 13 completely edentulous patients, according to inclusion and exclusion criteria, to rehabilitate with mandibular overdentures retained by two dental implants and a complete denture as antagonists. We evaluated the efficacy of the treatment and its evolution in five steps: (i) initially, with the old complete dentures, (ii) after the implants' placement with the mandibular prosthesis relined, (iii) after the placement of the healing abutments, (iv) after the installation and adaptation of new prostheses, and (v) after a 3-month follow-up period. At each stage, we evaluated patients via temporal and masseter electromyography (EMG), molar and incisive bite force, and QoL.

RESULTS

The results for EMG found a decrease in muscle activity during rest, the mastication of raisins, and lateral movements when the overdentures were installed. For the bite force and QoL, there was a gradual improvement from the placement of the healing abutments period (P ˂ 0.05), which was sustained until the follow-up.

CONCLUSIONS

Comfort and stability improved during the treatment, demonstrated by the QoL and bite force results. These results are positive for elderly patients who might refuse an implant-supported overdenture due to treatment length.

Retrospective Analysis of Implant Overdenture Treatment in the Advanced Prosthodontic Clinic at the University of Illinois at Chicago

The aim of the present retrospective study was to evaluate the clinical outcomes of implant-supported overdenture treatment provided by prosthodontic specialty residents. Twenty-three patients with 25 implant-supported overdentures (IODs) participated in the study. Seventy-four implants were placed by periodontic, prosthodontics, or oral and maxillofacial surgery students. All prostheses were fabricated in the advanced prosthodontics clinic at University of Illinois at Chicago. The condition of the peri-implant soft tissue, implants, and prostheses were evaluated. Complications and any maintenance were documented. Patients completed an oral health impact profile-14 and semantic differential scale questionnaires. Statistical analyses were performed using SPSS statistical software. Twenty mandibular and 5 maxillary IODs were evaluated. Ninety-seven percent of the attachments were locators (Zest Anchors) and 3% ball attachments. None of the implants had lost osseointegration, but 14 implants (19%) had developed marginal bone loss in one-third of the implant length or more. Fourteen (19%) implants had developed dehiscence, which ranged from 1 to 4 mm. A variation in the width of the keratinized tissue, gingival, plaque, and calculus index was observed. There was a statistically significant relationship between the presence of plaque and the bleeding on probing on the buccal aspect of implants (P = .012). The incidence of dehiscence was significantly higher on the midfacial when the keratinized tissue was less than 2 mm (P &lt; .0001). The majority of the complications were prosthetic in nature, such as broken denture teeth (74%) and worn or loose matrices (35%). Debris was observed in 19% of the locator abutments, and 36% of the overdentures were not stable in application of anterior force. Patients were compliant with oral hygiene protocols and their chewing ability was high (mean = 8.0). The overall experience was pleasant (mean = 7.5); the treatment provided good esthetics (mean = 8.3) and great satisfaction (mean = 8.5). From an educational and clinical perspective, IOD therapy has been documented to be a predictable and successful treatment option. Patients should be informed of the required maintenance and the possible complications related to IOD therapy.

Fixation of a severely resorbed mandible for complete arch screw-retained rehabilitation: A clinical report

Severely resorbed mandibles with placed endosteal dental implants can fracture. Therefore, techniques to reduce the risk or minimize the consequences of these fractures are needed. This clinical report presents a technique for placing a titanium plate in a severely resorbed mandible subjected to complete-arch implant therapy. The titanium plate is placed in the same surgical procedure as the implants, allowing immediate implant loading. This technique provides safe implant-supported treatment for patients with severe mandibular resorption.

Comparison of marginal bone loss and patient satisfaction in single and double-implant assisted mandibular overdenture by immediate loading

PURPOSE

The purpose of this study was to compare the coronal bone level and patient satisfaction in 1-implant and 2-implant assisted mandibular overdentures.

MATERIALS AND METHODS

Twenty patients who had maladaptive mandibular dentures were treated in this study. Patients were randomly divided into two groups. The first group received 1 implant (Simple line II, Implantium, South Korea) in their mandibular midline and the second group received 2 implants in their B and D regions (according to Misch's category). If the primary stability of each implant was at least 60 ISQ, ball attachment was placed and denture relined with soft liner. After 6 weeks, retentive cap incorporated with hard acrylic resin. In the 6 and 12 months recalls, periapical digital radiograph were made and visual analogue scale questionnaires were used to record patient satisfaction. The Friedman test was done for comparing the presurgical and postsurgical parameters in each group and the U-Mann Whitney test (P<.05) was done for comparison of post-treatment results between the two groups.

RESULTS

All implants achieved sufficient primary stability to be immediately loaded. Patient satisfaction was high, and there were no significant differences between two groups (P>.05). In addition, mean marginal bone loss was 0.6 ± 0.67 mm in the first group and 0.6 ± 0.51 mm in the second group, after 12 month. Mean marginal bone loss showed no significant differences between two groups.

CONCLUSION

This preliminary one-year result indicated that mandibular overdentures anchored to a single implant can be a safe and cost-effective method as a starting step for implant-overdenture treatment.

Design and manufacture of customized dental implants by using reverse engineering and selective laser melting technology

STATEMENT OF PROBLEM

Recently a new therapeutic concept of patient-specific implant dentistry has been advanced based on computer-aided design/computer-aided manufacturing technology. However, a comprehensive study of the design and 3-dimensional (3D) printing of the customized implants, their mechanical properties, and their biomechanical behavior is lacking.

PURPOSE

The purpose of this study was to evaluate the mechanical and biomechanical performance of a novel custom-made dental implant fabricated by the selective laser melting technique with simulation and in vitro experimental studies.

MATERIAL AND METHODS

Two types of customized implants were designed by using reverse engineering: a root-analog implant and a root-analog threaded implant. The titanium implants were printed layer by layer with the selective laser melting technique. The relative density, surface roughness, tensile properties, bend strength, and dimensional accuracy of the specimens were evaluated. Nonlinear and linear finite element analysis and experimental studies were used to investigate the stress distribution, micromotion, and primary stability of the implants.

RESULTS

Selective laser melting 3D printing technology was able to reproduce the customized implant designs and produce high density and strength and adequate dimensional accuracy. Better stress distribution and lower maximum micromotions were observed for the root-analog threaded implant model than for the root-analog implant model. In the experimental tests, the implant stability quotient and pull-out strength of the 2 types of implants indicated that better primary stability can be obtained with a root-analog threaded implant design.

CONCLUSIONS

Selective laser melting proved to be an efficient means of printing fully dense customized implants with high strength and sufficient dimensional accuracy. Adding the threaded characteristic to the customized root-analog threaded implant design maintained the approximate geometry of the natural root and exhibited better stress distribution and primary stability.