Worn denture teeth of a full-arch implant-supported fixed dental prosthesis: A technique to restore

Worn denture teeth continue to be a significant complication with implant-supported prostheses. This article discusses a case report that used an intraoral scanning system to restore an existing maxillary implant-supported prosthesis with significant posterior occlusal wear.  IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) restorations were fabricated and cemented to the prepared posterior denture teeth to re-establish the occlusal vertical dimension and to help prevent further wear of the occlusal surfaces.

The Use of Splinted Versus Nonsplinted Prosthetic Design in Dental Implants: A Literature Review

The choice of a splinted or nonsplinted implant-supported prosthesis should be based on solid scientific evidence that considers the conditions and needs of each patient. This review elaborates on the factors that directly influence clinical decisions between splinted or nonsplinted dental implants. Digital and manual searches of the published literature were conducted to identify studies that examined splinted prostheses (SPs) and nonsplinted prostheses (NSPs). The search terms used, alone or in combination, were "splinting prosthesis," "nonsplinting prosthesis," "prosthetic design," "stress distribution in dental implant," "implant loading," "implant occlusion," and "crestal bone resorption." Ninety-four studies were selected to compare and address the details emphasized in this study. Thirty-four reported articles were not directly related to restoration design but were reviewed to better understand the influence of mechanical risk factors, finite element analysis limits, and criteria for implant survival and treatment success. There are advantages and disadvantages of splinting implants together. NSPs are the ideal choice because they resemble natural teeth. Splinting a restored implant will cause the implant to appear as part of one unit and is indicated in more compromised situations, unfavorable conditions, or when pontic spaces and cantilevers are needed in implant prostheses.

Digital workflow for proximal adjustment of teeth adjacent to implant-supported fixed restorations using a predesigned computer-aided grinding guide

Clinically, the proximal surfaces of teeth adjacent to an implant restoration usually need to be adjusted to build a preferable adjacency relationship. However, it is difficult for freehand preparation to get a favorable proximal contour in some cases. In the workflow presented here, virtual grinding can be made to adjacent teeth, under the consideration of functional reconstruction and biological requirements, and then the grinding can be implemented using digital templates and a specialized bur. This allows for more precise and accurate adjustments to be made during the clinical procedure, reducing the risk of over- or under-preparation of the proximal surfaces. In addition, the use of specialized diamond burs and grinding guides can make the procedure more efficient and streamlined, reducing the time required for proximal adjustment and minimizing patient discomfort. The resulting implant-supported prosthesis is more likely to function properly and last longer, as the precise proximal contacts can help distribute occlusal forces more evenly across the dentition. Overall, the use of digital technology for precise adjustment of proximal contacts during implant restorations represents an important advancement in modern dentistry, enabling dentists to provide their patients with more accurate, efficient, and effective dental care.

Comparing Original and Universal Screwdrivers and How They Affect Friction in the Screw

The present study focused on investigating whether universal screwdriver kits cause less friction between the screwdriver and the abutment screw than original screwdrivers. For this purpose, 2 original screwdrivers (Straumann and BEGO) and a universal screwdriver kit (bredent) were investigated. On 1 implant per screwdriver, 26 abutments were properly attached one after the other with the corresponding abutment screws. After tightening the abutment screw, the force required to pull the screwdriver off the screw head was determined with a spring balance. For both manufacturers, greater pull-off forces were measured when using the original screwdrivers than when using the universal screwdriver. The pull-off force (mean ± SD) required for the Straumann original screwdriver was 3.7 ± 1.4 N, while that required for the universal screwdriver was 0.1 ± 0.1 N (P < .001). The pull-off force was 1.5 ± 1.5 N for the BEGO original screwdriver and 0.7 ± 0.9 N for the universal screwdriver (P = .19). Using original manufacturer-supplied screwdrivers could thus minimize the risk of the screwdriver slipping out of the screw head during dental treatment and being swallowed or aspirated by the patient.

Median mandibular flexure-the unique physiological phenomenon of the mandible and its clinical significance in implant restoration

Mandibular flexure, characterized by unique biomechanical behaviors such as elastic bending and torsion under functional loading, has emerged as a crucial factor in oral clinical diagnosis and treatment. This paper presents a comprehensive review of the current research status on mandibular flexure, drawing insights from relevant studies retrieved from the PubMed database (www.ncbi.nlm.nih.gov/pubmed), including research conclusions, literature reviews, case reports, and authoritative reference books. This paper thoroughly explores the physiological mechanisms underlying mandibular flexure, discussing different concurrent deformation types and the essential factors influencing this process. Moreover, it explores the profound implications of mandibular flexure on clinical aspects such as bone absorption around dental implants, the precision of prosthesis fabrication, and the selection and design of superstructure materials. Based on the empirical findings, this review provides crucial clinical recommendations. Specifically, it is recommended to exert precise control over the patients mouth opening during impression-taking. Those with a high elastic modulus or bone-tissue-like properties should be prioritized when selecting superstructure materials. Moreover, this review underscores the significance of customizing framework design to accommodate individual variations in facial morphology and occlusal habits. Future research endeavors in this field have the potential to advance clinical diagnosis and treatment approaches, providing opportunities for improvement.

The clinical significance and application of the peri-implant phenotype in dental implant surgery: a narrative review

Background and Objective

In recent years, the concept of the peri-implant phenotype has become a new standard for the clinical evaluation of the soft and hard tissues surrounding dental implants. Improving this phenotype enhances the likelihood of achieving long-term favorable results and is a necessary consideration during implant planning. Stable peri-implant tissue support is also crucial for the functional and aesthetic value of implant restoration. Herein, the authors review the clinical significance of the peri-implant phenotype and assess the timing of treatment strategies for improving peri-implant phenotype elements.

Methods

A literature search was performed to retrieve papers on peri-implant tissue management and clinical outcomes published up to November 24th, 2022 in PubMed, Web of Science, EMBASE, and Scopus.

Key Content and Findings

The optimal time to improve peri-implant bone thickness (PBT) is with augmentation procedures before implant surgery or at the same time as first-stage surgery. Similarly, issues associated with keratinized mucosa width (KMW) and mucosal thickness (MT) should be addressed before final restoration. The establishment of supracrestal tissue height (STH) depends on the MT and implant depth of the patient. Furthermore, special attention should be paid to the effect of the peri-implant phenotype on the prognosis of immediate implant placement in the aesthetic zone.

Conclusions

The long-term success of implant restoration depends on careful planning that considers appropriate interventions for improving the peri-implant phenotype at different stages of treatment to reduce iatrogenic variables.

Implant position and guided placement for in-house-produced CAD/CAM restorations with titanium (Ti)-bases

Digital dentistry has contributed to the evolution and simplification of dental implantology over the last decade. The incorporation of intraoral scanners, CBCT, 3D implant-planning software, and CAD/CAM systems makes prosthetically driven implantology a straightforward process. Such digital resources for treatment planning and execution, following evidence-based concepts, have the ability to improve the long-term esthetics and function of implant-supported restorations as well the long-term survival of dental implants. Dental implants are frequently considered as the first treatment option for replacing failing or missing teeth. However, their use in the esthetic zone remains a challenge for many clinicians. The present article provides clinical guidelines for ideal implant positioning employing computer-guided surgery and chairside CAD/CAM-fabricated provisional and definitive restorations with titanium (Ti)-bases for successful prosthetic outcomes, optimizing gingival architecture, and decreasing overall treatment duration. (Int J Comput Dent 2023;26(1):75-0; doi: 10.3290/j.ijcd.b3818287).

Clinical outcomes of implant-supported monolithic zirconia crowns and fixed partial dentures: A systematic review

PURPOSE

To determine the survival rates of implant-supported monolithic zirconia crowns and fixed partial dentures (FPD).

MATERIAL AND METHODS

An electronic search for articles in the English language literature published from January 1, 2001 to September 17, 2021 was performed using PubMed, Scopus, and CENTRAL search engines. After applying predetermined inclusion and exclusion criteria, the definitive list of selected articles was used for calculating the interval survival rate (ISR) and cumulative survival rate (CSR). Restoration failure in this study was defined as the fracture or compromise of any part of the ceramic restoration that required the removal or remake of the implant-supported restoration.

RESULTS

The electronic search resulted in 457 titles. The systematic application of inclusion and exclusion criteria resulted in 14 clinical studies that addressed the clinical outcomes of implant-supported monolithic zirconia crowns and fixed partial dentures. Of these, 3 were randomized controlled trials, 5 were prospective studies, and 6 were retrospective studies. Follow-up periods ranged from 1 to 5 years. Of the 644 implant-supported monolithic zirconia restorations computed in this systematic review, there was only 1 reported failure of the monolithic zirconia restorative material over a follow-up period of up to 5 years, for a cumulative survival rate of 99.84%. At the maximum follow-up interval of 5 years, the cumulative survival rate for monolithic zirconia single crowns was 100% and the cumulative survival rate for monolithic zirconia fixed partial dentures was 99.60%.

CONCLUSIONS

Implant-supported monolithic zirconia single crowns and fixed partial dentures have excellent short-term (<5 years) survival rates but the evidence for medium-term survival (>5 years) and beyond is lacking.

Removal of broken screws on implant abutment by digital guide plate: A case report and literature review

Implant restoration is currently the most mainstream method for repairing missing teeth. With the increasing number of plantings, various planting complications begin to be paid attention to. Among them, there are many reports of disability phenomena such as loose and broken abutment screws and broken top screws, which cause the implant to fail or fail to function. In recent years, with the development of computer-aided software and its application in the field of oral treatment, digital guide plates based on 3D printing of oral CBCT scanning data are widely used in oral implants. Therefore, we explore the application prospect of post-core crown restoration after removing broken screws from the implant abutment with a digital guide plate. We reported a case of upper right first molar implant abutment screws broken, which were removed by a digital guide plate and customized turning bur. The resin-matrix ceramics crown post core was prepared, and then the occlusal force was tested by the T-ScanIII system. It provides a reference for the application of digital guide plates in special cases such as broken screws of implant abutment.

Clinical performance of zirconia implant abutments luted to a titanium base - a retrospective cross-sectional study

AIM

To evaluate the survival of implant-retained restorations fabricated on CAD/CAM-derived zirconia abutments luted to a titanium base.

MATERIALS AND METHODS

153 patients who received a total of 310 dental implants (Camlog Promote plus or Xive S) and all-ceramic restorations on yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) abutments luted to a titanium base during the last 10 years were included. Patients were examined for technical complications during routine visits. Crestal bone level changes were randomly analyzed based on periapical radiographs of 75 implants.

RESULTS

Among the included 153 patients, 17 ceramic chippings (5.5%), 6 abutment loosenings (1.9%), and 2 abutment fractures (0.6%) were identified. The mean follow-up time was 4.7 years (standard deviation [SD]: 1.94), with a follow-up period of up to 10 years (maximum). Kaplan-Meier estimation resulted in a survival rate without complications of 91.6% for the restoration and 97.4% for the abutment. There was no statistically significant difference between the two implant systems, either between implant location or regarding the complication rate of the type of restoration. For the 75 implants included in the radiographic analysis, the mean bone level change was 0.384 mm (SD: 0.242, 95% CI: 0.315 to 0.452) for the Camlog implant system and 0.585 mm (SD: 0.366, 95% CI: 0.434 to 0.736) for the Xive system (P = 0.007).

CONCLUSION

The results of the present retrospective study demonstrate acceptable clinical outcomes for zirconia abutments luted to a titanium base in combination with all-ceramic restorations. The assessed abutment design does not appear to have a negative impact on peri-implant hard tissue.

Microbiological Comparison of Different Sealing Materials for the Access Holes of Implant Restorations

PURPOSE

To evaluate the performance of sealing materials used in the screw-access holes of screw-retained implant final superstructures in vivo and in vitro.

MATERIALS AND METHODS

Twenty-one screw-access holes in the final superstructures were randomly divided into three groups (each group, n = 7). Following disinfection and isolation, all access holes were initially filled with sterilised cotton pellets of the same weight. Depending on the group, the access holes were finally sealed with either provisional composite restorations (group A), self-curing resin for provisional sealing (group B), or acrylic resin (group C). After one month of the functional period, the inner cotton pellets were collected as bacterial reservoirs.

RESULTS

Total aerobic bacteria and total gram-negative anaerobic bacteria were measured after bacterial culture for 48 h and 72 h, respectively. In vitro evaluation of porosity using scanning electron microscopy (SEM) was also performed. Samples from superstructures sealed with provisional composite restorations showed fewer bacteria and less porosity than samples from superstructures sealed with self-curing resin for provisional sealing and acrylic resin. In this study, provisional composite restorations showed the best sealing properties. Provisional composite restorations may prevent bacterial invasion of the access holes of the final superstructures.

CONCLUSION

In this study, provisional composite restorations showed the best sealing properties. Provisional composite restorations may prevent bacterial invasion of the access holes of the final superstructures.

Replacement of an existing maxillary anterior fixed dental prosthesis, redo another fixed dental prosthesis, or convert to implants

OBJECTIVE

The purpose of this article is to discuss the considerations that need to be evaluated when considering the replacement of an existing maxillary anterior fixed dental prosthesis (FDP) with another FDP, or when to consider converting to implants and individual crowns on the previous abutment teeth.

OVERVIEW

The need to replace unesthetic or failing maxillary anterior FDPs is something all restorative dentists will be faced with multiple times in their careers. Given the emphasis over the past few decades on utilizing implants for tooth replacement as opposed to a tooth supported FDP, the question becomes when is converting the existing FDP to implants and single crowns an appropriate choice, as opposed to redoing a new FDP. This article will focus on the risks of choosing to convert to an implant solution, and the risks of redoing the tooth supported FDP. Multiple systematic reviews on each approach will be used to aid in the decision process. The most significant risks for both approaches will be identified, and a chart of the key parameters to assess will be presented, along with their impact.

CONCLUSIONS

The statistical outcomes at 5 and 10 years of tooth supported FDPs, and Implant based restorations are very similar if certain clinical parameters are met, namely vital healthy abutment teeth for the FDP, and adequate bone and soft tissue for the implant-based restoration. If one abutment tooth is compromised the long-term prognosis drops significantly and converting to an implant-based restoration may be more predictable. Similarly, if adequate bone and soft tissue cannot be obtained through surgical augmentation procedures, using a connective tissue graft for the ridge, and redoing the FDP may obtain a more acceptable esthetic result.

CLINICAL SIGNIFICANCE

A significant number of maxillary anterior FDPs exist that will need replacement in the future. Given the desire of many dentists to utilize implants when possible, there can be a tendency to automatically treatment plan an implant-based approach for replacement of the existing FDP. Certainly, most clinicians would favor an implant-based tooth replacement rather than preparing unrestored teeth to place an FDP, but when an existing FDP exists, the teeth have already been prepared for full coverage in most instances. In addition, for most long term existing FDPs, there is a significant change in the vertical and horizontal dimension of the bone and soft tissue that can make getting an acceptable esthetic result with an implant challenging. This article provides a systematic approach to identifying when redoing the FDP may be preferable, or when converting to an implant-based approach is a better choice.

Peri-implant disease caused by residual cement around implant-supported restorations: a clinical report

Cement-retained restorations on implants ensures better passive fit and aesthetics, simplicity of fabrication and a homogenous load distribution during function, compared to screw-retained restorations, but it is associated to biological complications following the difficulty to remove cement excess. In fact, residual cement is a predisposing factor to peri-implant tissue inflammation and periimplantitis, because promotes plaque retention of bacteria, due to rough surface. This is especially true since radiographs should not reveal the cement excess and cements commonly used for the cementation of implantsupported prostheses have poor radiodensity. This report documents a case of clinical and radiographic findings of peri-implant disease associated with excess cement extrusion. Two months after cement removal, resolution of inflammation occurred. A good method of cementation, an accessible margin of restoration and the use of ZnOE cement instead of methacrylate cement, should help to prevent cementrelated peri-implant disease.

The application of locking-taper implants in posterior area implant restoration with insufficient occlusal-gingival distances

OBJECTIVE

We aimed to investigate the effect of locking-taper implants on restoration in the posterior teeth area with insufficient occlusal-gingival distances.

METHODS

Forty-five patients undergoing dental implants in our hospital with occlusal-gingival distances under 5 mm in the posterior teeth area were recruited for this retrospective study. A total of 78 locking-taper implants were implanted in these patients. The patients were followed up for two years to observe the implant retention rate, the implant bone heights at different time points after the restoration, and the effects of the different implant placement depths on the marginal bone mass at the implants. Meanwhile, we evaluated the peri-implant soft tissue status by measuring the modified plaque index, the gingival index, and probing the depths. The postoperative complications and the patient satisfaction levels were also analyzed.

RESULTS

During the 2-year follow-up, the patients' implant retention rate was 100.00%. The implant placement depths did not affect the marginal bone masses at the implants at T0-T1 or T1-T2 (T0: the day after the restoration, T1: at one year after the restoration, T2: at two years after the restoration, all P>0.05). The peri-implant soft tissues in most of the patients were in good condition, and only a few patients had a small amount of plaque or slight gingival swelling. The average probe depth was 3.23±1.20 mm during the follow-up. Only one patient had abutment loosening, and one had a dental prosthesis fall off. The patients did not feel any numbness, continuous pain, or other abnormalities during the follow-up, and the overall patient satisfaction rate was over 97.78%.

CONCLUSION

Locking-taper implants can achieve good clinical outcomes in the restoration of the posterior area with insufficient occlusal-gingival distances. The implants can achieve a high implant retention rate, have no adverse effects on the peri-implant soft tissues, have a low complication rate, cause no significant marginal bone mass loss at the implants, and have a high patient satisfaction rate.

[Interarch distance is a target restorative space value: clinical decisionmaking of implant restoration guided by measured value]

When design an implant restoration for edentulous patients, many doctors ignore the sufficiency of the interarch distance (vertical distance) or horizontal distance of the patient to accommodate the superstructure and restoration before designing the implant plan. However, the connotation of measuring the interarch distance or horizontal distance has not been clarified in clinical practice. It is often based on visual estimation after operation, and the decision-making path of implant restoration is inverted, resulting in many mistakes regarding the restoration after implantation. The main reason is the lack of standardized paths and practical methods to use before surgery. This article recommended initially establishing a maxillo-mandibular relationship based on natural teeth, old dentures, or new ones and then using the height and horizontal distance or angle of the target restorative space, which was easier to grasp as the measured index. The minimum vertical distance (including the height of the gingival surface and the bone surface) and the horizontal distance (or the angle from the bone or gingival surface to the proposed occlusal plane) should be measured before operation. A decision tree of edentulous jaw restoration guided by the values of the repair space was established based on the measured values. This article clarified the measuring points and planes and thus provided a quantitative relationship basis for the design of implant restoration.

Fracture strength of various titanium-based, CAD-CAM and PFM implant crowns

OBJECTIVE

CAD-CAM has dramatically advanced dental restorative procedures to include implant-supported crowns. The purpose of this study was to compare the fracture resistance following mechanical loading and thermocycling of various screw-retained and cement-retained ceramic and polymethylmethacrylate material combinations using the TiBase abutment compared to PFM implant-supported crowns.

OVERVIEW

Twelve implant restorations were fabricated for each of eight groups. Three groups were screw-retained and five groups were cement-retained implant restorations. The ceramic and polymethylmethacrylate restorations were fabricated on the TiBase abutment while the PFM restorations were fabricated on an UCLA abutment. Data were analyzed with a one way Analysis of Variance and Tukey's post-hoc test to evaluate the effect of abutment and crown type on fracture load (alpha = 0.05). A significant difference was found in the maximum fracture load between groups (P < 0.001).

CONCLUSIONS

The screw-retained implant restorations demonstrated higher fracture loads than their cement-retained counterparts. The TiBase abutment compared favorably to the UCLA abutment.

CLINICAL SIGNIFICANCE

The TiBase abutment is a titanium insert which combines the esthetics of a ceramic abutment with the mechanical properties of a titanium abutment and should be considered a viable clinical alternative to the conventional implant-supported PFM crown based on theses in vitro results and in context of in vivo studies. The lithium disilicate hybrid abutment/crown implant-supported restoration utilizing the TiBase abutment may be an ideal clinical choice due to simplicity, single appointment CAD-CAM, and esthetics.

[Precise investigation of digital guide plates applied to implant surgery of anterior teeth]

OBJECTIVE

To study the precision of digital guide plates applied to the implant surgery of anterior teeth.

METHODS

Fifty patients scheduled to receive implant restoration treatment in anterior teeth were enrolled in this study and divided into two groups (n=25, each group): those who were given routine implant restoration treatment (control group, 45 implants) and those who received implant restoration treatment using a digital guide plate (test group, 51 implants). After implantation, planned and placed implants were superimposed using digital software, and deviations (corona, apex, depth, degree) were analyzed. Esthetic parameters were assessed at 1 week (baseline), 6 month, and 1 year post final restoration. Pink esthetic (PES) and white esthetic (WES) scores were respectively used to evaluate the soft tissue and restoration esthetic outcome.

RESULTS

The deviation parameters in the test group were significantly lower than those in the control group (P<0.05). PES and WES values recorded for the control group at 1 week, 6 month, and 1 year post final restoration were significantly lower than those in the test group (P<0.05).

CONCLUSIONS

The digital guide plate can improve the accuracy of the three-dimensional position of implants in the maxillary esthetic zone. As such, this device may play an important role in obtaining the ideal aesthetic effects of maxillary anterior teeth.

The influence of abutment disconnections on peri-implant marginal bone: A systematic review

PURPOSE

To assess the failure rate of dental implants and prosthetic restoration, complications and marginal bone loss (MBL) of implants restored with an immediate definitive abutment at the time of the implant placement, and implants that were evaluated according to a standard prosthetic protocol (SPP), which includes multiple abutment changes.

MATERIALS AND METHODS

This systematic review followed the guidelines of the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). An electronic search with no date or language restriction was run in January 2018 in the PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, and complemented with a manual search. Randomised clinical trials with at least a 12-month follow-up evaluating the use of a definitive abutment and a SPP were included. The Cochrane Collaboration Risk of Bias tool was used to evaluate the included studies. The outcome measures were: implant and prosthetic failure; aesthetics; complications; and peri-implant MBL. The results were pooled using a random-effect model with mean differences (MDs) for continuous outcomes and risk ratio for dichotomous outcomes with a 95% confidence interval (CI).

RESULTS

The search identified a total of 714 studies. After the screening process five studies were included in the analysis. The five studies included had a limited sample size, a short follow-up period, and four studies were considered at high risk of bias. The meta-analysis revealed that five studies using an immediate definitive abutment over a 12- to 18-month follow-up resulted in lower MBL, with a MD of -0.32 mm (95% CI -0.45 to -0.19: P < 0.0000). At the end of a 3-year follow-up two studies showed a MD of -0.33 mm (95% CI -0.63 to -0.03: P = 0.03, which also favours the definitive abutment group. Regarding implant failure rate, complications, and probing depth, no significant difference was found between the groups.

CONCLUSIONS

Within the limitations of this meta-analysis, reducing the number of abutment changes contributes to statistically significant lower MBL. However, the clinical significance of this reduction in bone loss should be interpreted with caution. A high implant success rate was reported by all studies for both control and test groups.

"Simpli5y" a noval concept for fixed rehabilitation of completely edentulous maxillary and mandibular edentulous arches: A 3-year randomized clinical trial, supported by a numerical analysis

BACKGROUND AND PURPOSE

To evaluate the clinical outcome of "simpli5y" concept where in 3 and 2 implant placed cross arch in maxilla and in mandible respectively, restored with screw retained prosthesis.

MATERIALS AND METHODS

Total of 30 patients were randomized, with 15 in group1 with an average of 45 Ncm insertion torque with delayed loading and 15 in group 2 with above 65 Ncm inertion torque with immediate loading with equal number of male and female in each group following parallel design with 3 implants in maxillary and 2 implants in mandibular arch placed which was supported by a 3Dimensional finite analysis comparing the stress dissipation around implants of this concept-"Simplif5y" with All-on-4 concept.

RESULTS

Von Mises strain recorded in the bone in the maxillary and mandibular arch models were higher in All-on-four than that in the "simpli5y", which was vice-versa in the framework. Three-year post loading marginal peri implant bone loss for the group 1 was less than group 2.

CONCLUSIONS

These results, suggest that in both delayed loading and immediate loading protocol that cross arch prostheses can be successfully supported by 3 and 2 implants in maxillary and mandibular arch respectively-"Simpli5y" concept of full mouth restoration.

Evaluation of the influence exerted by different dental specialty backgrounds and measuring instrument reproducibility on esthetic aspects of maxillary implant-supported single crown

OBJECTIVE

To evaluate the influence exerted by different dental specialty backgrounds as well as the validity and reproducibility of the Pink Esthetic Score/White Esthetic Score (PES/WES) and the modified Implant Crown Aesthetic Index (mod-ICAI) on the assessment of esthetic aspects of maxillary implants supported single-tooth prosthesis.

MATERIAL AND METHODS

A total of fourteen examiners (Two orthodontists, two prosthodontists, two oral surgeons, two periodontists, two dental technicians, two dental assistants, and two postgraduate students in Implant Dentistry evaluated 20 photographs of single-implant-supported crowns and five photographs of unrestored teeth of esthetic zone in a two part study. The examiners assessed the photographs with each index (Pink Esthetic Score/White Esthetic Score and modified Implant Crown Aesthetic Index), twice with a week's interval. Orders of photographs were rearranged in the second assessment.

RESULTS

Kruskal-Wallis test results showed significant differences among all the six specialties (P ≤ 0.001). DAs and periodontists had significantly better ratings than other specialties with both indices. Prosthodontists had the lowest mean rank scores regardless of the index. Interobserver agreement was also lowest between the two prosthodontists (4-28%), rest of the groups had low-to-moderate agreement (20-80%) when limited allowance was accepted. With mod-ICAI, more interobserver agreement was noted within the specialty group than with PES/WES.

CONCLUSIONS

The PES/WES and the modified ICAI can be reliable estimates of esthetic outcomes. The assessor degree of specialization affected the esthetic evaluation with both the PES/WES and the modified ICAI. DAs and periodontists were identified to provide more favorable ratings than other specialties while prosthodontists were most critical in this study. With modified ICAI, more interobserver agreement within specialty resulted. The interexaminer agreement may be increased if more tolerance of 1-2 points is considered.

Accuracy of digital versus conventional implant impressions

OBJECTIVE

The accuracy of digital impressions greatly influences their clinical viability in implant restorations. The aim of this study was to compare the accuracy of gypsum models acquired from the conventional implant impression to digitally milled models created from direct digitalization by three-dimensional analysis.

MATERIALS AND METHODS

Thirty gypsum and 30 digitally milled models, impressed directly from a reference model, were prepared. The models and reference model were scanned by a laboratory scanner, and 30 surface tessellation language datasets from each group were imported to an inspection software program. The datasets were aligned to the reference dataset by a repeated best-fit algorithm, and 10 specified contact locations of interest were measured in mean volumetric deviations. The areas were pooled by cusps, fossae, interproximal contacts, horizontal and vertical axes of implant position and angulation. The pooled areas were statistically analysed by comparing each group to the reference model to investigate the mean volumetric deviations accounting for accuracy and standard deviations for precision.

RESULTS

Milled models from digital impressions had comparable accuracy to gypsum models from conventional impressions. However, differences in fossae and vertical displacement of the implant position from the gypsum and digitally milled models compared to the reference model exhibited statistical significance (P < 0.001, P = 0.020, respectively).

CONCLUSION

Milled models from digital impression are comparable to gypsum models from conventional impression.

[Research on gingival healing situation after stage II surgery of dental implantation for periodontitis patients]

OBJECTIVE

This study aimed to investigate the duration of gingival healing after the stage II surgery of dental implantation for periodontitis patients and to provide clinical guidelines for implant restoration.

METHODS

Twenty-nine periodontitis patients who had implantation surgery and achieved osseointegration were operated with stage II surgery (a total of 60 pieces of implants). The height of buccal gingival of each implant was measured twice after the stage II surgery. All implants were measured at the lowest point ofbuccal gingival after one week. The implants were randomly divided into four groups according to the schedule of the next test time: group one at one week from the initial test point, group two at two weeks, group three at three weeks, and group four at four weeks. Each group includes 15 pieces of implants. The amount of the buccal gingival change in each group between the second and first tests was determined, and the data were analyzed statistically.

RESULTS

The amount of gingival change of groups one, two, three, and four was (-0.25 +/- 0.66), (-0.04 +/- 0.52), (-0.70 +/- 0.77), and (-0.74 +/- 1.09) mm, respectively. No significant difference was observed between groups one and two in terms of the amount of gingival changes (P > 0.05). However, a significant difference was found between groups two and three (P < 0.05), and the amount of gingival recession was 0.66 mm. No significant difference was found between groups three and four (P > 0.05), and the gingival achieved stability.

CONCLUSION

The gingival recession achieves stability at the fourth week (after 28 d) after stage II surgery. At this time, the implant can be restored, and the abutment can be selected according to the amount of gingival change of the periodontitis patient.