A preliminary investigation into the ultrastructure of dental calculus and associated bacteria

Conometric Connection for Implant-Supported Crowns: A Prospective Clinical Cohort Study

BACKGROUND

Traditional screw or cemented connections in dental implants present limitations, prompting the exploration of alternative methods. This study assesses the clinical outcomes of single crowns and fixed partial prostheses supported by conometric connections after one year of follow-up.

METHODS

Twenty-two patients received 70 implants, supporting 33 rehabilitations. Biological responses and prosthodontic complications were evaluated at baseline, 6 months, and 12 months.

RESULTS

All implants exhibited successful osseointegration, with no losses or peri-implant inflammation. Marginal bone levels showed minimal changes, well below pathological thresholds. The difference in marginal bone loss (MBL) was -0.27 ± 0.79 mm between T0 and T1, and -0.51 ± 0.93 mm between T0 and T2. No abutment screw loosening or crown chipping occurred. However, coupling stability loss was observed in nine cases.

CONCLUSIONS

The conometric connection demonstrated successful integration and minimal complications after one year. This alternative shows promise, particularly in simplifying handling and improving marginal adaptation. Further research with larger sample sizes and longer follow-up is warranted for comprehensive validation.

The Conometric Connection for the Implant-Supported Fixed Prosthesis: A Narrative Review

Aim: The conometric concept was proposed as a possible connection between the abutment and the prosthetic coping. This research aimed to review the features and possible clinical uses of this connection in an implant-supported fixed prosthesis. Methods: An electronic search was conducted on an online database for the topic in object; articles published in international literature were considered and the research gave 17 results, and 6 parameters were analyzed. Results: This connection eliminated the possibility of cement residues in the subgingival region, reducing the risk of inflammation of peri-implant soft and hard tissues; not having to remove the cement residues, it is possible to place the margins in more apical portions, improving the aesthetics outcomes of the rehabilitations. It is also known that the retention by means of a screw causes a weakening of the restoration. The retentive force is adequate for fixed rehabilitation even after a high number of insertion–disengagement cycles; in vitro studies have also shown a high bacterial sealing. Implant rehabilitation using preformed components, such as conometric hoods, is helpful for CAD/CAM, so a digital workflow is possible. Several types of prosthesis were presented, all of which demonstrated adequate clinical performance in the follow-up observation. Conclusions: This type of connection seems to be suitable to support fixed implant rehabilitations, but long-term clinical studies are needed to validate this system.

Development of calcium bodies in Hylonsicus riparius (Crustacea: Isopoda)

Calcium bodies are internal epithelial sacs found in terrestrial isopods of the family Trichoniscidae that contain a mineralized extracellular matrix that is deposited and resorbed in relation to the molt cycle. Calcium bodies in several trichoniscids are filled with bacteria, the function of which is currently unknown. The woodlouse Hyloniscus riparius differs from other trichoniscids in that it possesses two different pairs of calcium bodies, the posterior pair being filled with bacteria and the anterior pair being devoid of bacteria. We explored the development of these organs and bacterial colonization of their lumen during the postmarsupial development with the use of optical clearing and whole-body confocal imaging of larval and juvenile stages. Our results show that calcium bodies are formed as invaginations of the epidermis in the region of intersegmental membranes during the postmarsupial development. The anterior pair of calcium bodies is generated during the first postmarsupial manca stage, whereas the posterior calcium bodies first appear in juveniles and are immediately colonized by bacteria, likely through a connection between the calcium body lumen and the body surface. Mineral is deposited in calcium bodies as soon as they are present.

Bacterial Viability within Dental Calculus: An Untrodden, Inquisitive Clinico-Patho- Microbiological Research

INTRODUCTION

Chronic inflammatory periodontal diseases i.e. gingivitis and periodontitis are one of the most common afflictions faced by human beings. Dental plaque, which is a pool of pathogenic microorganisms, remains to be current mainstay in etiopathogenesis. Dental calculus, which is a mineralized product of this plaque remains ignored and is considered merely as an ash heap of minor significance. However, the intriguing array in disease etiopathogenesis bulldozed researchers to suspect the role of calculus in disease chrysalis but still the viability of bacteria inside calculus and thus its pathogenicity remains an intricacy; the answer to which lies in the Pandora's Box.

AIM

The present study was undertaken to investigate the viability of bacteria within dental calculus along with their identification. Also, to classify dental calculus on the basis of mineralization and to observe the variation of viable microflora found in dental calculus with the extent of mineralization and disease severity.

MATERIALS AND METHODS

A total of 60 samples were obtained, by harvesting two samples of supragingival calculus from each patient having chronic inflammatory periodontal disease. These samples were divided into two groups (Group A and Group B). Samples of Group A were kept non-irradiated and samples of Group B were exposed to UV radiation. The samples were categorized into less, moderately and highly mineralized according to the force required for crushing them. All the crushed calculus samples were then divided into three parts. These were used for dark-field microscopy, gram staining and bacterial cultures. Bacterial identification of the cultures obtained was also carried out by performing various biochemical assays.

RESULTS

The present study revealed the presence of motile spirochaetes within the samples under dark-field microscope. Gram staining revealed presence of numerous gram positive cocci and gram negative bacilli. Bacterial cultures showed growth of variety of aerobic and capnophilic microorganisms.

CONCLUSION

The present study concludes the presence of viable aerobic and capnophilic bacteria inside dental calculus which may reside within the lacunae and channels in the calculus.

Biophysics of biofilm infection

This article examines a likely basis of the tenacity of biofilm infections that has received relatively little attention: the resistance of biofilms to mechanical clearance. One way that a biofilm infection persists is by withstanding the flow of fluid or other mechanical forces that work to wash or sweep microorganisms out of the body. The fundamental criterion for mechanical persistence is that the biofilm failure strength exceeds the external applied stress. Mechanical failure of the biofilm and release of planktonic microbial cells is also important in vivo because it can result in dissemination of infection. The fundamental criterion for detachment and dissemination is that the applied stress exceeds the biofilm failure strength. The apparent contradiction for a biofilm to both persist and disseminate is resolved by recognizing that biofilm material properties are inherently heterogeneous. There are also mechanical aspects to the ways that infectious biofilms evade leukocyte phagocytosis. The possibility of alternative therapies for treating biofilm infections that work by reducing biofilm cohesion could (1) allow prevailing hydrodynamic shear to remove biofilm, (2) increase the efficacy of designed interventions for removing biofilms, (3) enable phagocytic engulfment of softened biofilm aggregates, and (4) improve phagocyte mobility and access to biofilm.

A morphological survey of root grooves and their influence on periodontal attachment loss

Periodontal health reflects a balance between harmful and protective elements in the gingival marginal area. The total plaque mass, specific periodontopathogens, the tooth morphology, and local environmental factors may challenge this balance. The periodontal ligament attachment loss shifts this balance adversely toward the periodontal disease.

OBJECTIVES

The aim of this retrospective study was to determine the significance of proximal root grooves as a risk factor in the periodontal attachment loss; the effect of their dimensions and locations has been evaluated.

MATERIALS AND METHODS

One hundred (100) extracted formalin stored single rooted permanent anterior teeth were studied by staining with 0.1% toludine blue to visualize attached periodontal ligament remnants. On each tooth, the loss of attachment was measured from the cemento-enamel junction to the most coronal level of the stained periodontal ligament remnants.

RESULTS

The prevalence of proximal root grooves was found to be 81% and a statistically significant greater loss of attachment was present on grooved than on non-grooved surfaces (p < 0.01).

CONCLUSIONS

Generally, there was direct relationship between groove location, its dimensions, and maximum loss of attachment. The results suggest that proximal root grooves should be considered in periodontal diagnosis, prognosis, and treatment planning.

Evidence for calcifying nanoparticles in gingival crevicular fluid and dental calculus in periodontitis

BACKGROUND

Calcifying nanoparticles (CNPs), also known as nanobacteria, can produce carbonate apatite on their cell walls and initiate pathologic calcification. The objective of this study was to determine whether CNPs are present in the gingival crevicular fluid (GCF) from subjects with periodontal disease and whether they can induce the pathologic calcification of primary cultured human gingival epithelial cells.

METHODS

GCF and dental calculus samples were collected from 10 subjects with gingivitis and 10 subjects with chronic periodontitis. CNPs in GCF and calculus filtrates were detected with nanocapture enzyme-linked immunosorbent assay kits. The CNPs in cultures of dental calculus filtrates were also identified using immunofluorescence staining, transmission electron microscopy (TEM), and chemical analysis. Pathologic changes in the CNP-treated gingival epithelial cells were observed with TEM, alizarin red staining, and disk-scanning confocal microscopy.

RESULTS

CNPs were found in GCF samples from two subjects with chronic periodontitis. Based on chemical analysis, the surface-associated material from CNPs isolated and cultured from calculus has a composition similar to dental calculus. The pathologic calcification of CNP-treated gingival epithelial cells was also observed.

CONCLUSIONS

Self-replicating calcifying nanoparticles can be cultured and identified from dental calculus. This raises the issue of whether CNPs contribute to the pathogenesis of periodontitis.

A new system to detect residual subgingival calculus: in vitro detection limits

AIM

We recently introduced an experimental surface detection system based on a conventional dental ultrasonic scaler. This device automatically discriminates cementum and dental calculus, which is the prerequisite for complete and thorough calculus removal. In the present study, the detection limits of this device were tested in vitro.

MATERIAL AND METHODS

From 50 extracted teeth, subgingival calculus was gradually removed using a Gracey curette. During this stepwise procedure, detection properties of the surface detection system were continuously monitored and systematically verified until the system stopped discriminating calculus from the root surface. By measuring the diameter, circumference and area of the smallest, yet recognizable deposit, and of the no longer recognizable deposit, the cut-off point of the discriminative capability of the detection device was determined.

RESULTS

The cut-off points for the correct classification of residual deposits averaged on a diameter of 219 microm, an area of 21,600 microm2, and a circumference of 748 microm. This means a sensitivity of 73% and a specificity of 80% in this critical area.

CONCLUSIONS

This calculus detection system was able to detect small deposits. In clinical practice, this device may support dentists in deciding whether to stop or to continue the debridement.