Prosthesis Survival Rates and Prosthetic Complications of Implant-Supported Fixed Dental Prostheses in Partially Edentulous Patients

Prosthetic Complications of Single Screw-Retained Implant-Supported Metal-Ceramic Fixed Prostheses: A Retrospective Observational Study

Purpose

To analyze prosthetic complications of single screw-retained implant-supported metal-ceramic fixed prostheses (SSIMCFPs).

Materials and Methods

A total of 457 medical records of patients treated with implants at the University Dental Clinic of the European University of Valencia from 2016 to 2022 were reviewed. Of the 335 SSIMCFPs evaluated, 222 were included. The following data were collected from medical records: age, sex, prosthesis location, implant diameter, type of antagonist, date of prosthesis placement, type of prosthetic complications, and the date of the occurrence of complications. Statistical analysis was estimated at the patient level with a simple binary logistic regression and at the prosthesis level, a simple logistic regression with generalized estimating equation models (p  < 0.05).

Results

A total of 222 SSIMCFPs were placed in 159 patients. The prevalence of complications was 23.3% at the patient level, equivalent to 21.6% of SSIMCFPs. A total of 48 complications were collected; screw loosening was the most frequent complication (16.2%), followed by ceramic fracture (3.1%), screw fracture (1.8%), and implant fracture (0.5%). There were no cases of abutment fracture. The mean time of the loosening of the screw was 10.5 months and ceramic fractures at 6.9 months. The factors that most influenced the occurrence of prosthetic complications were posterior position (p  < 0.001), implant diameter from 3.5 to 4.8 mm (p  < 0.01), and lower arch position (p  < 0.05).

Conclusions

The most frequent complication of SSIMCFP was loosening of the screw followed by ceramic fracture. The appearance of these complications usually occurred during the first year after SSIMCFP placement. Factors related to the occurrence of complications were mandibular posterior location and implant diameter from 3.5 to 4.8 mm.

Digital workflow for prosthetic management of malpositioned implant in an adolescent patient: A 20-year follow-up

OBJECTIVE

Dental implants placed in adolescent patients pose a challenge to restore and maintain an esthetic outcome over longer period of follow-up. Maxillomandibular changes throughout adulthood may lead to complications such as implant infraocclusion and interproximal contact loss. This case report describes an alternate prosthetic treatment strategy for maxillary single implant placed in an adolescent patient in the esthetic zone with inappropriate implant axis and screw hole placement.

CLINICAL CONSIDERATIONS

With temporary restorations, the gingiva and soft tissues were shaped to imitate the emerging profile of the contralateral side. A zirconia screw-retained abutment was customized as a copy-mirror from the contralateral prepared tooth to mimic the exact shape and to avoid labiolingual over contour by computer-aided design/computer-assisted manufacture (CAD/CAM). The porcelain laminate veneer was bonded to the zirconia abutment. Porcelain adhesive approach was used instead of traditional principles of retention and resistance form of the abutment.

CONCLUSIONS

A functional and esthetic outcome was achieved and maintained, while a minimally invasive procedure was implemented to use the malplaced implant instead of explanting it.

CLINICAL SIGNIFICANCE

The present report illustrates the prosthetic management of a malpositioned dental implant placed 20 years ago, utilizing a minimally invasive digital protocol.

Analysis of Strain Distribution in Common Clinical Designs of Posterior Implant-Supported Fixed Partial Restorations: Comparison between Six Configurations

The configuration of implant-supported prostheses is considered to influence the magnitude of stress concentrations, affecting their survival rate. The purpose of this study is to determine, through strain gauge measurements during load application, the dispersion and magnitude of strain concentrations in different implant-supported prosthesis designs. All designs matched those commonly used in posterior partially edentulous states. Three implants were inserted into an epoxy resin model (PLM-4B Vishay Measurements Group Inc., Raleigh, NC, USA), allowing for the delivery of three- and four-unit crowns in different cemented configurations. Loads were applied at vertical and oblique directions over the cast crowns in six different configurations representing various posterior partially edentulous restorations. The readings from the strain gauges adhered to the implant necks' presented data on implant strain. Prostheses including cantilevers showed the highest strain among the three-unit prostheses within the prosthetic complex, and three single units showed the least (8133 µs vs. 201 µs, respectively). Angulated load application also had a role in amplifying the strains recorded, resulting in total strains of between 3.5 and 20 times higher than during vertical loading in all configurations. It can be concluded that the configuration of implant-fixed partial prosthesis changes the loads engaging the restoration, the implant, and, probably, the supporting bone.

Effect of dental implant therapy on the preservation of orofacial tissues: A systematic review and meta-analysis

OBJECTIVE

Fundamentally, this review addresses the following question: In partially or fully edentulous patients, do implant-supported dental prostheses preserve orofacial tissues when compared to conventional prostheses or no therapy?

MATERIALS AND METHODS

This study was conducted according to the 2020 PRISMA guidelines for systematic reviews. Electronic searches were conducted at PubMed and Embase databases followed by manual search. Clinical studies comparing the effect of implant-supported prostheses with conventional rehabilitation or no treatment on alveolar bone resorption, remaining teeth, and jaw muscle thickness were considered for inclusion. A qualitative synthesis was conducted with all included studies, and data from selected studies were pooled quantitatively to perform a meta-analysis.

RESULTS

A total of 14 studies were selected for analysis. Six studies reported on the effect of implant therapy on alveolar bone resorption (n = 453), six on the remaining teeth (n = 1014), while four studies evaluated masseter muscle thickness (n = 158). The results of the meta-analyses assessing alveolar bone resorption in the posterior mandible and in the anterior area of the maxilla, both fixed and random effects models, yielded no benefit of rehabilitation with implant-supported prostheses when compared to conventional prostheses. For masseter bone thickness, however, a significant benefit for implant-supported prosthesis was observed.

CONCLUSIONS

This systematic review and meta-analysis were unable to unequivocally answer the focus question. There are some indicators of the benefit of implant-supported prostheses over conventional prostheses or no therapy in preserving orofacial tissues, particularly for masseter muscle thickness. However, the evidence is still insufficient to confirm such perception.

Three-dimensional analysis of the interchangeability of a semiadjustable articulator system in service over time

STATEMENT OF PROBLEM

Some contemporary articulator systems claim to be highly precise in their interchangeability, with tolerances below 10 μm in vertical error; however, the claims have not been independently verified.

PURPOSE

The purpose of this study was to investigate the interchangeability of calibrated semiadjustable articulators in service over time.

MATERIAL AND METHODS

A calibrated mounting articulator served as the master articulator, while the test groups were used articulators with a minimum of 1-year use by predoctoral dental students (n=10); used articulators with a minimum of 1-year use by prosthodontic residents (n=10); and new articulators (n=10). One set of mounted maxillary and mandibular master models was positioned in the master and test articulators. High-precision reference markers on the master models were used to determine interarch 3D distance distortions (dR_R, dR_C, and dR_L), interocclusal 3D distance distortion (dR_M), interocclusal 2D distance distortions (dx_M, dy_M, and dz_M), and interocclusal angular distortion (dθ_M) relative to the master articulator. All measurements were conducted three times using a coordinate measuring machine and then averaged to derive the final data set.

RESULTS

For interarch 3D distance distortion, the mean dR_R ranged from 4.6 ±21.6 μm for new articulators to 56.3 ±47.6 μm for articulators used by prosthodontic residents; mean dR_C ranged from 65 ±48.6 μm for new articulators to 119.0 ±58.8 μm for articulators used by prosthodontic residents; and mean dR_L ranged from 12.7 ±39.7 μm for articulators used by prosthodontic residents to 62.8 ±75.2 μm for new articulators. For interocclusal 3D distance distortion, the mean dR_M ranged from 21.5 ±49.8 μm for new articulators to 68.6 ±64.9 μm for articulators used by predoctoral dental students. For the 2D distance distortions, the mean dx_M ranged from -17.9 ±43.4 μm for articulators used by predoctoral dental students to -61.9 ±48.3 μm for articulators used by prosthodontic residents; mean dy_M ranged from 18.1 ±59.4 μm for new articulators to 69.3 ±115.1 μm for articulators used by prosthodontic residents; and mean dz_M ranged from 29.5 ±20.2 μm for new articulators to 70.1 ±37.8 μm for articulators used by prosthodontic residents. Mean dθ_M ranged from -0.018 ±0.289 degree for new articulators to 0.141 ±0.267 degree for articulators used by prosthodontic residents. One-way ANOVA by articulator type revealed statistically significant differences among the test groups for dR_R (P=.007) and dz_M (P=.011) only, where articulators used by prosthodontic residents fared significantly poorer than the other test groups.

CONCLUSIONS

The new and used articulators tested did not fulfill the manufacturer's claim of accuracy of up to 10 μm in the vertical dimension. Up to 1 year of time in service, none of the investigated test groups fulfilled the criterion for articulator interchangeability, even if the more lenient threshold of 166 μm were accepted.

Chewing side preference and laterality in patients treated with unilateral posterior implant-supported fixed partial prostheses

BACKGROUND

It is not clear to what extent chewing is improved by unilateral oral rehabilitation with implant-supported fixed partial prostheses (ISFPPs).

OBJECTIVES

This study aimed to investigate whether patients treated with unilateral ISFPPs in the maxilla use their prostheses during mastication to the same extent as they used their contralateral natural teeth. A further aim was to investigate whether there is a correlation between preferred chewing side and laterality.

METHODS

Chewing side preference was assessed in 15 participants treated with unilateral ISFPPs in the maxilla. The first, second, third, fifth and tenth chewing cycles were assessed, and the test was repeated 10 times. All participants also answered a questionnaire about their chewing side preference.

RESULTS

Most of the participants presented bilateral chewing, but two (13%) chewed only on the ISFPP. There was no statistically significant association between the objectively assessed chewing side and dental status (natural teeth or ISFPPs) during any of the recorded chewing cycles (p > .1). There were statistically significant correlations between both the subjectively reported usually preferred chewing side and the subjective chewing side preference during the test and the objectively assessed chewing side for the first three chewing cycles (p < .01). No correlation was found between handedness and the objectively assessed chewing side.

CONCLUSION

In the present study, most participants chewed bilaterally, and chewing was performed both on the ISFPP and on the natural teeth. No correlation was found between the preferred chewing side, objectively or subjectively determined and laterality.

Long-Term Treatment Outcomes of Implant Prostheses in Partially and Totally Edentulous Patients

Implant dental therapy is a clinical procedure used for treating patients with tooth loss with known clinical success. This clinical study aimed to evaluate the long-term clinical outcomes of dental implants in partially and totally edentulous patients. A total of 544 Microdent (Microdent SU, Implant Microdent System®, Santa Eulàlia de Ronçana Barcelona, Spain) screw implants were placed in 111 patients using a two-stage surgical technique and a conventional loading protocol (lasting 3 months). Implant and prosthetic clinical findings were evaluated during a 15-year follow-up. A total of 6 implants were lost during the healing period, and 124 prostheses were placed over the 538 implants that remained: 20 single crowns, 52 partially fixed bridges, 45 full-arch fixed restorations, and 7 overdentures. A total of 20 of these were lost during the follow-up period. The cumulative survival rate for all implants was 96.4%. The data underwent statistical analysis (significance level: p < 0.05). The mean marginal bone loss was 1.82 ± 0.54 mm, ranging from 1.2 to 3.1 mm. The most frequent complications were mechanical prosthodontic complications (16.2%). In all, 11.8% of implants showed periimplantitis as the primary biological complication. Dental implants inserted in both the maxillary and mandibular areas produce long-term favorable outcomes and stable tissue conditions when a delayed loading protocol is followed.

Influence of interproximal peri-implant tissue and prosthesis contours on food impaction, tissue health, and patients' quality of life

PURPOSE

1) To investigate tissue features and interproximal contour of posterior implant supported single crowns (ISSC), which correlate with food impaction. 2) To evaluate the influence of food impaction on the health of the adjacent peri-implant tissue and patients' oral health related quality of life (OHRQoL).

MATERIALS AND METHODS

Patients with posterior ISSC under maintenance between July 2019 and July 2020 were recruited. OHRQoL of patients who self-reported food impaction between ISSC and teeth was evaluated by Oral Impacts on Daily Performance questionnaire and reported at patient level. Interproximal prosthesis contours and periodontal/peri-implant tissue conditions were assessed by clinical and radiographic examination. Differences between food impaction (FI) and non-food impaction (NFI) sites were analysed.

RESULTS

Totally 178 patients (286 ISSC and 410 interproximal spaces) were included. Among 119 patients who self-reported food impaction, 84 (70.6%) reported their OHRQoL to be affected with minor to severe intensity. The most common affected daily performance was the ability to clean the teeth. Plaque accumulation at ISSC, deeper probing depth, complete interdental papilla fill, loose contact, longer contact length, lower contact point level, closer distance between ISSC and tooth, lesser embrasure surface area, tissue level implant and cement-retained restoration were found significantly more in the FI group than the NFI group (P<0.05).

CONCLUSION

Interproximal features of the implant prosthesis were associated with food impaction between the ISSC and the adjacent tooth, which might affect periodontal and/or peri-implant tissue health conditions. Patients' OHRQoL was commonly affected by food impaction, but the intensity was low.

Prevalence and risk indicators of peri-implant diseases in a group of Moroccan patients

BACKGROUND

To report the prevalence of peri-implant diseases in a North African patient population, and to assess the concurrent associations of patient- and implant-level characteristics with probing depth and bone loss around dental implants METHODS: A total of 642 implants in 145 subjects were followed up for a mean 6.4 years. At the last follow-up visit the subjects were examined clinically and radiographically to assess the status of peri-implant tissues and teeth. Data analysis used the generalized linear mixed models RESULTS: The prevalence of peri-implant mucositis and peri-implantitis were 82.1% and 41.4% at the subject level, and 68.4% and 22.7% at the implant level, respectively. Inadequate plaque control, peri-implant inflammation, history of previous implant failures, and pain/discomfort at the implant site were significantly associated with both outcomes (increased probing depth and bone loss). Diabetes mellitus, inadequate implant restoration, single restorations (versus multi-unit), cement-retained restorations, and presence of occlusal wear facets on teeth were significantly associated with one of the two outcomes. Implants placed in the lower anterior jaw region had the most favorable outcome. Smoking, history of periodontitis, and type of implant surface did not show significant associations with higher frequency of peri-implant diseases in the multivariable analysis.

CONCLUSIONS

Peri-implant diseases are prevalent in this North African patient population. Multiple subject- and implant-level variables were associated with peri-implant diseases. Risk assessment of these effects should consist of a concurrent inclusion of these factors in multivariable analyses that also adjust for the complex variance structure of the oral environment.