Osseoperception following dental implant treatment: a systematic review

Halitosis and Pain Threshold of Peri-Implant Tissues: An Observational Cohort Study

In this study, we aimed to evaluate the halitosis and pain threshold of the peri-implant soft tissues in individuals rehabilitated with implant-supported prostheses. Forty-eight subjects were divided into four groups (n = 12) according to their prosthetic rehabilitation: single-tooth fixed prosthesis, multi-tooth fixed prosthesis, overdentures, and the Brånemark protocol. Halitosis was measured using a halimeter, whereas the pain threshold was measured using Von Frey monofilaments. Measurements were taken before (t0) and 30 days after (t1) placement of healing caps, and at the time of (t2) and 30 days after (t3) prosthetic placement. Halitosis data were analyzed using the chi-square test and Bonferroni correction (p < 0.05). Two-way ANOVA and Tukey's test (p < 0.05) were used to analyze pain threshold data. We noted an association between halitosis and time for the Brånemark protocol [X2(6) = 18.471; p = 0.005] and overdenture groups [X2(6) = 17.732; p = 0.007], and between halitosis and type of prosthesis only at t0 [X2(6) = 12.894; p = 0.045]. The interaction between time and the type of prosthesis significantly interfered with the mean pain threshold values (p = 0.001). At most time points, the majority of participants in each group had clinically unacceptable halitosis. After 30 days of using the prostheses, the overdenture group had a lower pain threshold compared to the Brånemark protocol group.

Digitally designed occlusion of an implant-supported crown considering physiological tooth displacement under occlusal loading

Physiological natural tooth displacement under occlusal loading can influence intraoral occlusal contacts. However, gypsum casts and digital scans cannot simulate the physiological tooth displacement under occlusal loading. The occlusal design of the implant-supported crowns has been based mainly on the experience of dental laboratory technicians, lacking accuracy and individualization. Therefore, a digital technique that considers physiological tooth displacement is presented to design the occlusion of implant-supported single crowns.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Assessment of physiological posterior-tooth displacement under habitual occlusal force by intraoral scanning using implant-supported crowns as the reference

STATEMENT OF PROBLEM

Studies that have used digital methods to quantitatively evaluate physiological tooth displacement under occlusal force are sparse.

PURPOSE

The purpose of this clinical study was to measure physiological posterior tooth displacement under occlusal force by intraoral scanning and reverse engineering technology by using implants as the reference.

MATERIAL AND METHODS

A total of 14 participants received 15 implant-supported single mandibular first molar crowns. The surface data of maxillary and mandibular posterior teeth (U1 and L1) and the buccal occlusal data in the maximum intercuspal position (MIP) with habitual occlusal force were obtained by using an intraoral scanner (TRIOS 3, v20.1.2). The U1 and L1 data were segmented into single teeth, which were then aligned to the buccal occlusal data by using the "best-fit alignment" command to build the data under occlusal force (U2 and L2). U1 and L1 data were compared with U2 and L2 data to calculate the centroid and functional cusp vertex displacements and the long axis deflections of the second premolars and second molars, taking the first molar as the reference. The medians, and first quartile (Q₁), third quartile (Q₃) of the above data were reported, and the Shapiro-Wilk and Wilcoxon tests were used to analyze the differences (α=.05).

RESULTS

Under occlusal force, the median (Q₁, Q₃) centroid displacements of posterior teeth ranged from 61 (52, 101) μm to 146 (80, 186) μm; the functional cusp vertex displacements ranged from 82 (62, 117) μm to 146 (98, 189) μm, and the long axis deflections ranged from 0.45 (0.25, 0.87) degrees to 1.03 (0.52, 1.41) degrees. Mandibular second premolars displaced lingually, mesially, and apically; mandibular second molars displaced distally and apically; and maxillary second premolars and second molars displaced lingually and apically.

CONCLUSIONS

A digital method taking implant-supported single crowns as the reference was used to demonstrate physiological posterior-tooth displacement under habitual occlusal force.

Digital replication and transfer of interim to definitive complete arch implant-supported fixed prostheses by using a laboratory scanner

The present technique describes an effective digital approach for the replication and transfer of occlusion, maxillomandibular relationship, and esthetic parameters from interim to definitive complete arch implant-supported fixed prostheses by laboratory scanning with transfer plates. Monolithic zirconia complete arch implant prostheses have been fabricated with satisfactory functional and esthetic outcomes.

Effect of a novel interocclusal recording method on occlusal accuracy of implant-supported fixed prostheses: A randomized clinical trial

OBJECTIVES

To investigate the effect of a novel interocclusal recording method on the occlusal accuracy of implant-supported fixed prostheses for partially dentate patients with distal extension.

MATERIALS AND METHODS

Twenty patients with two or more adjacent teeth missing in the distal extension and scheduled to receive implant-supported fixed prostheses were enrolled. Two interocclusal recording methods were used: placing polyvinyl siloxane (PVS) on the interocclusal recording caps (test), and placing PVS on healing abutments (control). The intraoral occlusal contacts in maximal intercuspal position (MIP) were compared with those in the mounted casts to calculate sensitivity and positive predictive value (PPV). Then, patients were randomly allocated into two groups to determine which interocclusal record would be used. The implant prostheses' evaluations mainly included occlusal adjustment height, volume, and time, occlusal contact score based on articulating paper examination. Paired-samples t-test, Mann-Whitney U test, and least squares regression analyzed the statistic differences.

RESULTS

The test method had higher sensitivity to detect intraoral occlusal contacts than the control method (p = .002), but similar PPV (p = .10). During the prostheses' evaluations, the occlusal adjustment height in the test group was significantly lower than that in the control group [99.4 (53.2, 134.2) vs. 159.0 (82.3, 247.8) μm, p = .03], while the occlusal contact score before adjustment was higher (p = .006). The groups had similar occlusal adjustment volume and time.

CONCLUSIONS

The novel interocclusal recording method for implant-supported fixed prostheses was more accurate and could reduce the occlusal adjustment.

Active Tactile Sensibility in Implant Prosthesis vs. Complete Dentures: A Psychophysical Study

BACKGROUND AND OBJECTIVES

Proprioceptive information from natural dentition and adjacent oral tissues enables correct masticatory function, avoiding damage to the teeth. Periodontium is the main source of this relevant information, and when a tooth is lost, all this proprioceptive sensibility relies on receptors from muscles, the mucous membrane or the temporomandibular joint, and this sensibility gets worse. Active tactile sensibility measures this proprioceptive capability in microns by psychophysical studies consisting of introducing thin metal foils between patients' dental arches during chewing to see if they are able to notice them or not. Osseoperception is a complex phenomenon that seems to improve this sensibility in patients wearing dental implants. The objective of this investigation is to measure this sensibility in different prosthetic situations by performing a psychophysical investigation.

MATERIAL AND METHODS

We divided 67 patients in three groups depending on their prosthetic situation and performed a psychophysical study by introducing aluminium foils of different thicknesses in order to establish an active tactile sensibility threshold in every group. We also measured variables such as prosthetic wearing time, age or gender to see how they may influence threshold values. We used Student's t-test and Mann-Whitney U tests to analyse these results.

RESULTS

Active tactile sensibility threshold values in implants are lower than those from complete dentures but higher than values in natural dentition. However, values in implants are closer to natural dentition than complete denture values. Age, gender or prosthetic wearing time have no influence in active tactile sensibility thresholds.

CONCLUSION

Active tactile sensibility threshold values depend on prosthetic rehabilitations and the mechanoreceptors involved in every situation. Implant prosthesis presents an increased active tactile sensibility thanks to osseoperception phenomenon.

In vivo measurement of three-dimensional load exerted on dental implants: a literature review

Background

For biomechanical consideration of dental implants, an understanding of the three-dimensional (3D) load exerted on the implant is essential, but little information is available on the in vivo load, including the measuring devices.

Purpose

This review aimed to evaluate studies that used specific load-measuring devices that could be mounted on an implant to measure the functional load in vivo.

Materials and methods

An electronic search utilizing the internet research databases PubMed, Google Scholar, and Scopus was performed. The articles were chosen by two authors based on the inclusion and exclusion criteria.

Results

In all, 132 studies were selected from the database search, and 16 were selected from a manual search. Twenty-three studies were finally included in this review after a complete full-text evaluation. Eleven studies were related to the force measurements using the strain gauges, and 12 were related to the piezoelectric force transducer. The principles of the two types of devices were completely different, but the devices produced comparable outcomes. The dynamics of the load magnitude and direction on the implant during function were clarified, although the number of participants in each study was small.

Conclusions

The load exerted on the implant during function was precisely measured in vivo using specific measuring devices, such as strain gauges or piezoelectric force transducers. The in vivo load data enable us to determine the actual biomechanical status in more detail, which might be useful for optimization of the implant prosthetic design and development of related materials. Due to the limited data and difficulty of in vivo measurements, the development of a new, simpler force measurement device and method might be necessary.

Ageing-Associated Transcriptomic Alterations in Peri-Implantitis Pathology: A Bioinformatic Study

Background

Ageing is associated with increased incidence of peri-implantitis but the roles of ageing-associated biological mechanisms in the occurrence of peri-implantitis are not known. This study is aimed at performing integrative bioinformatic analysis of publically available datasets to uncover molecular mechanisms related to ageing and peri-implantitis.

Methods

Gene expression datasets related to ageing and peri-implantitis (PI) were sought, and differentially expressed genes (DEGs) were analysed. Ageing-related genes were also identified from the “Aging Atlas” database. Using intersection analysis, an age-related-PI gene set was identified. Functional enrichment analysis for enriched GO biological process and KEGG pathways, protein-protein interaction (PPI) network analysis, correlation analysis, and immune cell infiltration analysis to determine high-abundance immune cells were performed. Least absolute shrinkage and selection operator (LASSO) logistic regression identified key age-related-PI genes. Transcription factor-gene and drug-gene interactions and enriched KEGG pathways for the key age-related-PI genes were determined.

Results

A total of 52 genes were identified as age-related-PI genes and found enriched in several inflammation-associated processes including myeloid leukocyte activation, acute inflammatory response, mononuclear cell differentiation, B cell activation, NF-kappa B signalling, IL-17 signalling, and TNF signalling. LYN, CDKN2A, MAPT, BTK, and PRKCB were hub genes in the PPI network. Immune cell infiltration analysis showed activated dendritic cells, central memory CD4 T cells, immature dendritic cells, and plasmacytoid dendritic cells were highly abundant in PI and ageing. 7 key age-related PI genes including ALOX5AP, EAF2, FAM46C, GZMK, MAPT, RGS1, and SOSTDC1 were identified using LASSO with high predictive values and found to be enriched in multiple neurodegeneration-associated pathways, MAPK signalling, and Fc epsilon RI signalling. MAPT and ALOX5AP were associated with multiple drugs and transcription factors and interacted with other age-related genes to regulate multiple biological pathways.

Conclusion

A suite of bioinformatics analysis identified a 7-signature gene set highly relevant to cooccurrence of ageing and peri-implantitis and highlighted the role of neurodegeneration, autoimmune, and inflammation related pathways. MAPT and ALOX5AP were identified as key candidate target genes for clinical translation.

Exploring the Integration Between Colour Theory and Biodiversity Values in the Design of Living Walls

Designing green infrastructure in cities requires vegetation that has multiple outcomes and functions, particularly using plants that have both attractive visual or aesthetic features and high biodiversity values. Plantings that have high visual appeal are more highly valued by people and increase their feeling of wellbeing. Increasing biodiversity in cities is one of the major challenges facing urban planning and design. However, balancing biodiversity and aesthetic outcomes in urban planting design is complex, and to date there are few methods that can be used to guide plant selection. To address this knowledge gap, we investigated the use of a colour theory framework for planting arrangements to see if we could design vegetation that is highly aesthetic and has high biodiversity. We did this by configuring planting combinations for living walls in Malmö, Sweden, using principles based on Johannes Itten’s colour theories. The plant combinations on each wall were graphically arranged using (1) colour analysis of each plant and (2) design of the plant species into two colour schemes: light-dark colour concept and a complementary colour concept. For each species used in the compositions we created a biodiversity classification, based on its pollination value, “nativeness” and conservation value as a cultivar; and a plant visual quality classification, based on the performance from living walls studies. The graphical colour composition and interlinked biodiversity value were then compared to designs created with randomly selected plant species. The results showed that it is possible to design a living wall based on colour theory without compromising with biodiversity outcomes, namely species richness, pollination and the nativeness of the species. The results also indicate the potential application of this design approach to deliver greater aesthetic appreciation and enjoyment from plantings. While more work is needed, this study has shown that a theoretical colour framework can be a useful tool in designing green infrastructure to improve delivery of both cultural and regulatory ecosystem services.

Occlusal change in posterior implant-supported single crowns and its association with peri-implant bone level: a 5-year prospective study

OBJECTIVES

This study aims to analyze the 5-year occlusal change in posterior implant-supported single crowns and the association between the relative occlusal force (ROF) and peri-implant bone level.

MATERIALS AND METHODS

Partially edentulous patients who had received implant-supported single crowns in the posterior region were included. Occlusal examinations with a computerized occlusion analysis system were conducted at 0.5, 3, 6, 12, 24, 36, 48, and 60 months after delivery of the implant-supported single crown. The ROFs of implant-supported single crowns, mesial adjacent teeth, and control natural teeth were recorded. Intraoral periapical radiographs were taken at each follow-up time to evaluate marginal bone level (MBL). Ordinary least square regression was used to analyze the association between ROF and MBL.

RESULTS

Thirty-seven posterior implant-supported single crowns in 33 participants (23.9 to 70.0 years) were followed up for 0.5 to 60 months [(42.4 ± 26.0) months]. The ROF of implant-supported single crowns increased from 2 weeks to 3 months (P < 0.01) and increased continuously between all two sequential time points from 6 to 36 months, with significant differences (P < 0.05). Then ROFs of implant-supported single crowns were significantly higher than those of control teeth at 48 and 60 months (P < 0.05). Regression analysis showed that ROF was significantly associated with MBL with a coefficient of 0.008 (P < 0.05).

CONCLUSION

The ROFs of posterior implant-supported single crown have significant change during 5 years' follow-up. The association between ROF and MBL has limited clinical significance.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR-ROC-17012240.

CLINICAL RELEVANCE

The occlusion of implant-supported single crowns should be carefully monitored during follow-up examinations, and occlusal adjustment should be considered to prevent overloading.