Edentulous Arches Research Articles

Accuracy of Extraoral Digital Impressions with Multi-Unit Implants

The aim of this in vitro study was to evaluate the accuracy of impressions made using two different silicones and corresponding stone casts in full-arch implant rehabilitation, using two laboratory scanners. A master model with six dental implants was created, scanned with a 12-megapixel scanner and used as digital master model. Ten implant impressions were obtained via two silicone impressions systems—Coltene® and Zhermack®—using the open-tray technique and poured gypsum. Two extraoral scanning systems (S600 ARTI Zirkonzhan® and Identica T500 Medit®) were used to scan the impressions and stone casts. Best-fit superimpositions were conducted between the master model and the virtual models obtained. A significance level of p < 0.05 was considered. The accuracy of the Medit® scanner was 82.26 [53.18; 111.34] µm for Coltene® silicone and 87.43 [72.00; 102.86] µm for Zhermack® silicone, and the accuracy of the Zirkonzhan® scanner was 69.90 [62.37; 77.43] µm for Coltene® silicone and 80.67 [65.77; 95.57] µm for Zhermack® silicone, without significant differences between scanners. When comparing the two silicones, no significant differences were found for the Medit® (p = 0.112) or Zirkonzhan® scanners (p = 0.162). The Zhermack® scanner showed better accuracy than the corresponding stone casts in the two scanners, Medit® (p = 0.019) and Zirkonzahn® (p = 0.002). The extraoral digitalization of impressions in edentulous dental arches with six implants proves to be a valid technique.

Clinico-Radiographic Research Evaluating Crestal Bone Level and Bone Density Surrounding Dental Implants.

Planning the surgical operation, choosing the type of implant, and the effectiveness of the implant all heavily rely on the quantity and quality of the accessible bone. This study's goal was to determine how promptly inserted dental implants affected postoperative changes in bone density and crestal bone level by Cone bean computed tomography (CBCT) gray-scale value during a follow-up of three to six months. A prospective clinical-radiographic investigation was conducted. Twenty participants with a partly edentulous arch who were also systemically healthy were chosen from the OPD of the Department of Periodontics and Oral Implantology. Each patient's oral hygiene status was noted, and a preoperative CBCT was performed to assess bone density. The following clinical parameters were noted before surgical procedures: plaque index (PI) (Silness and Loe, 1964), gingival index (GI) (Loe and Sillness, 1964), probing pocket depth (PPD), and primary stability. A weak connection between Hounsfield unit (HU) in three months and six months was found. Moreover, a slender positive connection between baseline primary stability and three months was found. PI was shown to have a statistically significant difference between the means at several follow-ups (P value of 0.0001). PI and probing depth were not statistically different between baseline and six months (P values = 0.0001) or between three months and six months (P values = 0.050), respectively. The main outcome of this study shows that insertion torque is directly proportional to bone density and crestal bone level.

An overview of dental implants biomaterials - A review

Modern day dentistry mostly utilizes Implants as the treatment of choice for partially or completely edentulous arches. The Implant biomaterial should be selected to optimize biologic performance, and maintain adequate function. This article aims to review a variety of Implant Biomaterials and different surface characterization to enhance osseointegration.

Enhancing intraoral scanner accuracy using scan aid for multiple implants in the edentulous arch: An in vivo study.

Intraoral scans of multiple implants in the edentulous arch are challenged by the absence of a distinct surface morphology between scan bodies. A scan aid was applied in such situation and evaluated for intraoral scanning accuracy in vivo. 87 implants in 22 patients were scanned with scan aid (SA) and without scan aid (NO) using two different intraoral scanners (CS3600 [CS] and TRIOS3 [TR]). Master casts were digitized by a laboratory scanner. Virtual models were superimposed using an inspection software and Linear deviation and precision were measured. Statistical analysis was performed using linear mixed models (α = .05). Total mean linear deviation within the CS group was 189 μm without scan aid and 135 μm when using the scan aid. The TR group's total mean deviation was 165 μm with and without a scan aid. Significant improvement with scan aid was observed for the CS group (p = .001), and no difference was found in the TR group. 96% of scan bodies were successfully scanned in the TR-SA group compared to 86% for the TR-NO group, 83% for the CS-SA, and 70% for the CS-NO group, respectively. The evaluated scan aid improved linear deviation compared to unsplinted scans for the CS group but not for the TR group. These differences could originate from different scanning technologies used, active triangulation (CS) and confocal microscopy (TR). The scan aid improved the ability to recognize scan bodies successfully with both systems, which could have a favorable clinical impact overall.

Techniques to Improve the Accuracy of Intraoral Digital Impression in Complete Edentulous Arches: A Narrative Review

Complete edentulous arches have been considered as one of the main limitations of intraoral scanners (IOSs). In these clinical scenarios, the accuracy of IOSs can be reduced because of several anatomical factors. To overcome these limitations, some studies have proposed several techniques to increase the accuracy of the impressions by means of various materials and instruments. The aim of this narrative review was to describe these techniques and to compare the obtained results to understand if it is currently feasible to increase the accuracy of the digital impressions of complete edentulous arches. An accurate analysis of the literature was performed using PubMed (National Library of Medicine) as well as manual searching without time and language restrictions. The results showed that there are few articles in the indexed literature on this topic, and that all are in vitro studies. Although the results of the analyzed studies were encouraging and reported useful in vitro results for artificial landmarks as well as for the use of an auxiliary geometry part related to the splinting of intraoral scan bodies (ISBs), clinical trials are needed to confirm that these techniques are feasible in daily clinical practice.

Accuracy and safety of a haptic operated and machine vision controlled collaborative robot for dental implant placement: Atranslational study.

Multiple generations of medical robots have revolutionized surgery. Their application to dental implants is still in its infancy. Co-operating robots (cobots) have great potential to improve the accuracy of implant placement, overcoming the limitations of static and dynamic navigation. This study reports the accuracy of robot-assisted dental implant placement in a preclinical model and further applies the robotic system in a clinical case series. In model analyses, the use of a lock-on structure at robot arm-handpiece was tested in resin arch models. In a clinical case series, patients with single missing teeth or edentulous arch were included. Robot-assisted implant placement was performed. Surgery time was recorded. Implant platform deviation, apex deviation, and angular deviation were measured. Factors influencing implant accuracy were analyzed. The in vitro results showed that with a lock-on structure, the mean (SD) of platform deviation, apex deviation, and angular deviation were 0.37 (0.14) mm, 0.44 (0.17) mm, and 0.75 (0.29)°, respectively. Twenty-one patients (28 implants) were included in the clinical case series, 2 with arches and 19 with single missing teeth. The median surgery time for single missing teeth was 23 (IQ range 20-25) min. The surgery time for the two edentulous arches was 47 and 70 min. The mean (SD) of platform deviation, apex deviation, and angular deviation was 0.54 (0.17) mm, 0.54 (0.11) mm, and 0.79 (0.22)° for single missing teeth and for 0.53 (0.17) mm, 0.58 (0.17) mm, and 0.77 (0.26)° for an edentulous arch. Implants placed in the mandible had significantly larger apex deviation than those in the maxilla. Cobot-assisted dental implant placement showed excellent positional accuracy and safety in both the in vitro study and the clinical case series. More technological development and clinical research are needed to support the introduction of robotic surgery in oral implantology. Trial registered in ChiCTR2100050885.

PROSTHETIC CONSIDERATIONS IN IMMEDIATE LOADING OF IMPLANTS- A NARRATIVE REVIEW

Immediate loading of implant is the placement of a definitive or a temporary prothesis within the first week of implant placement. The prosthesis connected to an immediately loaded implant may or may not be function depending upon the existing condition of the patients oral health. It has become a widely reported practice with a success rate comparable to a conventionally loaded implant. The success of an immediately loaded implant not only depends upon the survival of the implant but also the hard and soft tissue stability underneath the prosthesis. This paper narratively discusses about different factors affecting immediate loading and the guidelines of immediately loaded implants in partially or completely edentulous arches.

Face oriented digital workflow for transferring intraoral and extraoral data of edentulous arch rehabilitated with multiple implants: A clinical technique

A modified scan body system is described to preserve the occlusal vertical dimension and obtain intraoral and extraoral records to transfer to the dental laboratory technician for a complete arch fixed implant-supported prosthesis. This technique helps to effectively manage the orientation and articulation of the maxillary implants for 3-dimensional smile design.

Effect of the number and distribution of fiducial markers on the accuracy of robot-guided implant surgery in edentulous mandibular arches: An in vitro study

ObjectivesRobot-guided implant placement based on the screw marker-assisted registration technique has been applied in dentistry. This study aimed to identify the optimal number and distribution of fiducial markers for robot-guided implant placement in edentulous mandibular phantoms. MethodsFour implants were digitally planned and placed in edentulous mandibular phantoms under robotic guidance. Different numbers of fiducial markers (3, 4, 5, or 6) and distribution patterns (dispersed or localized) were used to register the robotic system. Platform, apex, and angular deviations were measured between the planned and actual implant positions using different numbers and distributions of fiducial markers. ResultsInserting six fiducial markers resulted in optimal implant position accuracy at the platform (0.53 ± 0.19 mm) and apex (0.59 ± 0.2 mm) deviations. However, the angular deviation did not differ significantly between different numbers of fiducial markers. Furthermore, the implant position accuracy did not differ significantly between the dispersed and localized distributions of fiducial markers. ConclusionIn robot-guided implant placement for edentulous mandibular arches, the insertion of six fiducial markers significantly increases the implant placement accuracy. Clinical SignificanceThe findings of this in vitro study may serve as a reference for clinicians to determine the optimal placement of fiducial markers and to facilitate the clinical application of robot-guided systems for implant placement in edentulous patients. Further clinical studies are necessary to confirm these findings.

COMBINE PROSTHESIS WITH PRECISION ATTACHMENT FOR DISTAL EXTENSION KENNEDY CLASS II ARCH- A CASE REPORT

Background: A prosthodontic rehabilitation's success depends critically on striking a balance between new and traditional treatment modalities.
 These prosthodontic treatment options include partial dentures with attachments. The majority of conventional RPD are adequately designed, but they are rarely utilised by patients because they don't like how they look or how well they retain information. This article describes a modified extended precision attachment for removing metal display to improve the aesthetics and preservation of a long-span partial edentulous arch restored using prosthodontic rehabilitation.
 A 68-year-old male patient was referred to the prosthodontics department for the purpose of replacing lost teeth. Kennedy's class I mode 1 in the mandibular arch with a worn out dentition were identified during clinical testing. Maxillary and mandibular arches were precisely planned for fixed and removable partial denture.
 The underlying residual alveolar ridge and the retentive components are both necessary for the RPD to be successful. In this case study, the use of precision attachments results in a more aesthetically pleasing end and enhanced retention on the mandibular partial dentures.
 Clinical significance: By applying precision attachment, the treatment plan adequately described restores the appearance, masticatory function, and enhances the prosthesis' retention.
 Keywords: Fixed partial denture, Flexible denture, Precision attachment,cast partial denture.

The Success and Complications of Complete-Arch Implant-Supported Fixed Monolithic Zirconia Restorations: A Systematic Review

In full-arch rehabilitation with implant-supported fixed prostheses, using monolithic zirconia seems to have several advantages regarding function and esthetics. However, the current scientific evidence is still limited. Thus, the aim of this investigation was to systematically review the literature on monolithic zirconia restorations for full-arch rehabilitation, particularly pursuing the survival rate and mechanical and biological complications. This study’s protocol was registered in PROSPERO (CRD42022301799). The primary literature search was performed in PubMed/MedLine and Web of Science, and a manual search was performed (checking cross-references). The focused question was, “In an adult population with one or both edentulous arches (P), the oral rehabilitation with implant-supported fixed-monolithic zirconia (full arch) (I), compared with oral rehabilitation using fixed-metal-ceramic prosthesis on implants (C), did show superior clinical results (O) in a minimum follow-up of 1 year (T)?” Inclusion and exclusion criteria were defined. Joana Briggs Institute tools were used to evaluate the quality of the studies. Meta-analysis was performed for the variable survival rate (%), applying the specific continuous moderator (follow-up). Data heterogeneity (I2) was assessed. From the initial search, 327 references were obtained. After eliminating duplicates and applying the inclusion/exclusion criteria by reading the titles, abstracts, and full text, seven articles were included. All included articles were observational longitudinal retrospective studies, with a number of prostheses between 7 and 2039. The mean age was 60 years, and the mean follow-up was 49.7 months. They had mandibular, maxillary, or bimaxillary rehabilitations, always with screw-retained retention, with an average survival rate of 97.23%. The number of implants ranged between four and eight. The quality of the articles was over 70%, and the heterogeneity was considered low (I2 = 28.64%). Within a mean follow-up of around four years, full-arch implant-supported monolithic zirconia rehabilitations had a high survival rate and minimal complications.

Prevalence of Temporomandibular Disorders among Patients with Partially Edentulous Arches - A Cross -Sectional Study

Prevalence of Temporomandibular Disorders among Patients with Partially Edentulous Arches - A Cross -Sectional Study

Complications in implant dentistry: A review of literature

Once an adult tooth is misplaced or lost, a patient may search for its replacement in order to restore his or her esthetics and function. Clinical dentistry, in the last few decades, has remarkably developed and enhanced in accordance with the evolution of scientific disciplines and individual’s requirements and demands. Traditional choices in dentistry for replacing a missing adult tooth involve the demountable partial denture, resin-bonded dental bridges, and full or partial coverage dental bridges. Implants have achieved wide acceptance and demand over time because they have the ability to restore function to almost normal in complete and partially edentulous arches. With considerable studies available, implants are highly admitted as a good treatment choice for the substitution of missing teeth these days. While implants are widely becoming an effective choice for missing tooth replacement, the complications and risks related to them are also progressively appearing.

Evaluation the Scanning Accuracy of Blue-Light Laboratory Scanners in Complete Edentulous Maxilla with Multiple Implants with Titanium Scan Bodies

To evaluate the accuracy of complete arch scanning with multiple implant titanium scan bodies using laboratory scanners. A master model of an edentulous maxillary arch with 6 implants was fabricated. Titanium scan bodies were inserted into the model. Three laboratory scanners were used: D2000 (3Shape), Vinyl High Resolution (Smart Optics), and inEos X5 (Dentsply Sirona). The master model was consecutively scanned ten times using dental laboratory scanners (LS) without detaching and repositioning the scan bodies. Linear and angular accuracy between adjacent implants was measured using inspection software (Control X, Geomagic). The accuracy of the complete arch scans was calculated. Implant regions were defined as; parallel (R1: #24-26 and #16-14), angled (R2: #22-24 and #14-12), angled to occlusal plane (R3: #12-22), and cross-arch (R4: #16-26). The effect of LS and implant region on accuracy was compared using two-Way ANOVA (α=0.05). Significant greater linear distortion was noted in R4 (61.2±17.9µm) compared to R1 (23.4±15.5µm) and R2 (26±17.7µm) (p<0.01). Greater linear distortions were noted in R4 with D2000 (0.07±0.016 degrees) and Vinyl High Resolution (0.067±0.02 degrees) than inEos X5 (0.032±0.021 degrees) (p>0.05). Greater mean linear precisions were noted in R1 (9±8µm) and R3 (9.3±8.3µm) than R4 (12.6±10.3µm) (p<0.05). The highest linear precision was noted in D2000 (7.2±7.6µm) (p<0.05). The angular precision of D2000 (0.02±0.015 degrees) was the highest (p<0.01). The angular precision of R4 (0.036±0.018 degrees) was the lowest (p<0.01). This study revealed that the trueness was affected by the implant region and the precision was affected by both LS and implant region.

Evaluation of the trueness and precision of conventional impressions versus digital scans for the all-on-four treatment in the maxillary arch: An in vitro study.

To compare the accuracy of digitizing conventional impressions to intraoral surface scans for all-on-four treatment in the maxillary arch. An edentulous maxillary arch model with four implants placed in an all-on-four design was fabricated. Intraoral surface scans (n=10) were obtained using an intraoral scanner after scan body insertion. For conventional polyvinylsiloxane impressions of the model, implant copings were inserted into the implant fixation for implant level, opened tray impressions (n=10). The model and conventional impressions were digitized to obtain digital files. A reference file was created using a laboratory-scanned conventional standard tessellation language (STL) file with analog to scan the body using exocad software. STL datasets from the two digital and conventional impression groups were superimposed with reference files to assess the 3D deviations. Two-way ANOVA and paired-samples t-test was performed to assess the difference in trueness and examine the effects of impression technique and implant angulation on the deviation amount. No significant differences were found between the conventional impression and intraoral surface scan groups F(1, 76)=2.705, p=0.104. No significant differences were found between conventional straight and digital straight implants and between conventional and digital tilted implants F(1, 76)=.041, p=0.841. No significant differences were found between conventional straight and conventional tilted implants p=0.07 and between digital straight and digital tilted implants p=0.08. Digital scans were more accurate than conventional impressions. The digital straight implants were more accurate than the conventional straight implants, and the digital tilted implants were more accurate than the conventional tilted implants, with higher accuracy for digital straight implants.

Managing Fibrous Maxillary Ridge: A Case Series of Impression Techniques.

Fibrous ridges on the edentulous maxillary arch are commonly found in combination syndrome or due to ill-fitting dentures. Often, these cases are managed conservatively using modified impression techniques to achieve better support and peripheral seal without displacing the movable tissue. Many impression techniques were proposed and justified with their respective ideologies, but some may complicate both the clinical and laboratory procedures. In this report, two simplified techniques are demonstrated to make an impression of the maxillary arch with fibrous ridges. Laboratory steps in custom tray fabrication are also emphasised for a successful and predictable impression.

Impact of intraoral scanner, scanning strategy, and scanned arch on the scan accuracy of edentulous arches: An in vitro study

Statement of problemThe scanning strategy used when making complete arch digital scans affects the accuracy of the scan, and the accuracy of the strategy may be influenced by the scanner used. However, these effects have not been investigated thoroughly with complete arch edentulous scanning. PurposeThe purpose of this in vitro study was to determine the effect of scanning strategies and the scanned arch on the accuracy of complete arch edentulous scans using 2 intraoral scanner (IOS) systems. Material and methodsTwo IOSs were used (TRIOS 4 and Emerald S) to scan maxillary and mandibular typodonts using 6 scanning strategies (test scans), and conventional impressions of both arches were also made. By using a metrology software program, test scans were superimposed onto a reference scan, and the root mean square (RMS) of the absolute deviation values was calculated to express trueness. The sample with the best trueness was used as reference onto which the remaining samples from the same group were superimposed, and the RMS of the absolute deviation values was calculated to express precision. Statistical modeling was applied using the fixed effects models (α=.05). ResultsThe main effects of scanner and strategy significantly impacted the trueness RMS values (P<.001), with significant interactions between them (P=.012). The main effects of scanner, strategy, and arch significantly impacted the precision of RMS values (P=.004), (P=.033), and (P=.023). Conventional impressions and the TRIOS 4 scanner had comparable accuracy, while the Emerald S scanner was inferior to both. P-O-B had the highest overall accuracy and strategy ZZ had the worst. Better precision was found with the maxillary arch. ConclusionsThe scanner type and scanning strategy significantly impacted the accuracy of the digital scans of completely edentulous arches, with a significant interaction between scanner and strategy. The arch being scanned had a significant effect on scan precision but not on scan trueness.

Clinical outcomes of full-arch immediate fixed prostheses supported by two axial and two tilted implants: A retrospective cohort study with 12-15 years of follow-up.

To retrospectively assess clinical and radiographic outcomes of immediately loaded full-arch fixed prostheses supported by axial and tilted implants up to 15 years of function. Patients with one completely edentulous arch received an immediate full-arch fixed prosthesis supported by two anterior axial and two posterior tilted implants. Definitive prosthesis consisting of a CAD-CAM titanium framework and acrylic teeth was delivered 6months later. Patients were regularly followed to assess clinical parameters and marginal bone level (MBL) change. Multilevel regression analysis was performed to investigate factors affecting implant failure and MBL. Six hundred ninety-two implants were placed in 72 maxillae and 101 mandibles. Seven maxillary implants (5 axial and 2 tilted) in 6 patients and 12 mandibular implants (6 axial and 6 tilted) in 5 patients failed. 15-year cumulative implant survival was 97.51% and 96.91% in maxilla and mandible, respectively (p=.64). After 10 years, the difference in MBL between axial and tilted implants was not significant in the maxilla (p=.47, 65 patients), while it was in the mandible (p < .001, 80 patients). Significant higher bone loss was reported in the mandible at both 5- and 10-year follow-up (p < .001 and p=.004, respectively). Mixed-effect multilevel linear regression evidenced a correlation between arch and bone loss at 5- and 10-year follow-up, while no correlation was found with age, gender, smoking, diabetes, and history of periodontal disease. This long-term study suggests that the present technique can be considered a viable treatment modality for the immediate rehabilitation of both maxilla and mandible.

Electromyographic Evaluation of Muscle Activity in Patients Rehabilitated with Full Arch Fixed Implant-Supported Prostheses

Background and Objectives: Implant rehabilitation of complete edentulous arches has become more and more popular because of the increased access of the population to this type of treatment. Furthermore, the development of new rehabilitation procedures can be applied in most clinical cases, including in those with severe atrophy. Hence, this study aimed to assess the functional changes that can occur in the stomatognathic system after implant rehabilitation procedures. Materials and Methods: A total of 63 patients were accepted in the study. They were divided into a first control (dentate) group (CG) and a second study group (edentulous, SG). For the latter, 30 patients received 204 two-stage implants immediately loaded with provisional prostheses. Surface electromyography (EMG) was assessed at the time of prostheses fixation, while for some patients it was applied six months after the fixation of the fixed prostheses, as well. These supplemental investigated patients formed a third, follow-up study group (FSG). All assessments were performed during the processes of clenching and mastication. The obtained data of the two study groups, SG and FSG, were compared with those of the control group, CG. Results: No statistical differences were found in the electrical muscular activity between the study and control groups during both clenching and mastication (p > 0.05). In addition, there were no differences within the same study group, both initially and after 6 months. The only changes were noticed between static and dynamic values for the right masseter muscle in the follow-up group FSG (p = 0.008). Deviations of the overlapping coefficients were similar for all groups (p = 0.086): for CG, 20.5%, median 11.1 (min. 0, max. 104); for SG, 21.4%, median 12.2 (min. 0, max. 103); for FSG, 36.1%, median 26.9 (min. 0, max. 160). This revealed no neuromuscular adaption to the prostheses. Conclusions: Implant-prosthetic rehabilitation led to an EMG activity that was similar to that of dentate patients immediately after the placement of the fixed implant-supported prostheses. Moreover, the measured values did not change after six months of functioning for all evaluated parameters. This may point to an immediate restoration of the muscle contraction capacity, without the necessity of adaptation over time. The study serves as an argument for the application and reliability of the immediate fixed implant-supported prostheses from the perspective of muscle adaptation and functioning.

Minimally invasive rehabilitation with total removable implants supported prosthesis with conometric connection

Since its inception, modern dentistry has been a discipline in continuous evolution. Thanks to this progress, the prosthetic rehabilitation of the edentulous patient can now be effectively addressed by multiple therapeutic approaches rooted in the decision-making marriage between patient and clinician in both partial and total edentulous patients. From a historical perspective, the aesthetic-functional restoration of the completely edentulous maxillary arch has been subverted in the possibilities of intervention by the introduction of implantology, which has made it possible to overcome the otherwise mandatory use of removable devices with complete mucous support (1). The current study is intended to be an example of this evolution by describing one out of five clinical cases performed. Furthermore, it is intended to demonstrate how the newly proposed implant-prosthetic techniques, where a fixed implant rehabilitation is not possible due to age constraints, lack of bone support or unfavourable mechanical-aesthetics parameters, allow the rehabilitation of the upper total edentulous jaw with a removable device without a solidarizing intermediate bar to rely upon for the implants. The implants and the whole rehabilitation are, however, consolidated thanks to the stability provided by the presence of a telescopic connection, combining viable long-term survival (2) with optimal results for the patient in terms of cost (3), comfort, chewing capability (4), aesthetics and home hygiene.