Periapical tissue reactions after pulp exposure in rat molars

The canonical Wnt/β-catenin signaling pathway is crucial for reparative dentinogenesis following tooth damage, and the modulation of this pathway affects the rate and extent of reparative dentine formation in damaged mice molars by triggering the natural process of dentinogenesis. Pharmacological stimulation of Wnt/β-catenin signaling activity by small-molecule GSK-3 inhibitor drugs following pulp exposure in mouse molars results in reparative dentinogenesis. The creation of similar but larger lesions in rat molars shows that the adenosine triphosphate (ATP)–competitive GSK-3 inhibitor, CHIR99021 (CHIR), and the ATP noncompetitive inhibitor, Tideglusib (TG), can equally enhance reparative dentine formation to fully repair an area of dentine damage up to 10 times larger, mimicking the size of small lesions in humans. To assess the chemical composition of this newly formed dentine and to compare its structure with surrounding native dentine and alveolar bone, Raman microspectroscopy analysis is used. We show that the newly formed dentine comprises equal carbonate to phosphate ratios and mineral to matrix ratios to that of native dentine, both being significantly different from bone. For an effective dentine repair, the activity of the drugs needs to be restricted to the region of damage. To investigate the range of drug-induced Wnt-activity within the dental pulp, RNA of short-term induced (24-h) molars is extracted from separated roots and crowns, and quantitative Axin2 expression is assayed. We show that the activation of Wnt/β-catenin signaling is highly restricted to pulp cells in the immediate location of the damage in the coronal pulp tissue with no drug action detected in the root pulp. These results provide further evidence that this simple method of enhancement of natural reparative dentinogenesis has the potential to be translated into a clinical direct capping approach.

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Histological observations on pulpal and periapical tissue reactions after pulp exposure of developing molars.

THE JOURNAL OF THE STOMATOLOGICAL SOCIETY JAPAN ◽

10.5357/koubyou.52.288 ◽

1985 ◽

Vol 52 (2) ◽

pp. 288-347

Author(s):

Junji Kato

Keyword(s):

Pulp Exposure ◽

Tissue Reactions

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641 What Is the Most Reliable Way to Secure A Surgical Drain?

British Journal of Surgery ◽

10.1093/bjs/znab134.157 ◽

2021 ◽

Vol 108 (Supplement_2) ◽

Author(s):

B Hughes ◽

J Stallard ◽

S Jivan

Keyword(s):

Suture Material ◽

Suture Techniques ◽

Robust Method ◽

Suturing Technique ◽

The Moment ◽

Tissue Reactions ◽

Surgical Drain

Abstract Introduction Surgical drains are used by many specialities, we aim to determine the most robust method of securing them by comparing suturing technique, material and fixation angle. Method A Blake’s drain was inserted into a piece of pork belly and secured using a standard ‘three half hitch’ technique with 3.0 Silk, EthilonTM and ProleneTM . For each suture type, drains were sutured in line, at 45 and 90 degrees to the course of the drain. The force needed for the suture to failure was measured and each repeated 3 times. Different suture techniques were then used to determine the strongest fixation. Results With the drain exiting inline the moment of failure was, on average, 1.25kg for silk, 3.5kg for EthilonTM and 4.0kg for ProleneTM. Increasing drain fixation angle required more force for the suture to fail. With EthilonTM and ProleneTM, the suture snapped before the drain slipped. Three half hitches was the strongest technique. Conclusions Suture material, technique and drain fixation angle had an impact on suture strength with ProleneTM outperforming Silk. We advocate using a ‘three half hitch’ technique with 3.0 ProleneTM to secure a surgical drain. It offers superior strength whilst reducing the risk of localised tissue reactions.

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Revealing Inflammatory Indications Induced by Titanium Alloy Wear Debris in Periprosthetic Tissue by Label-Free Correlative High-Resolution Ion, Electron and Optical Microspectroscopy

Materials ◽

10.3390/ma14113048 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3048

Author(s):

Rok Podlipec ◽

Esther Punzón-Quijorna ◽

Luka Pirker ◽

Mitja Kelemen ◽

Primož Vavpetič ◽

...

Keyword(s):

Titanium Alloy ◽

High Resolution ◽

Wear Debris ◽

Ion Beam ◽

Quantitative Measure ◽

Label Free ◽

Periprosthetic Tissue ◽

Correlative Microscopy ◽

X Ray ◽

Tissue Reactions

The metallic-associated adverse local tissue reactions (ALTR) and events accompanying worn-broken implant materials are still poorly understood on the subcellular and molecular level. Current immunohistochemical techniques lack spatial resolution and chemical sensitivity to investigate causal relations between material and biological response on submicron and even nanoscale. In our study, new insights of titanium alloy debris-tissue interaction were revealed by the implementation of label-free high-resolution correlative microscopy approaches. We have successfully characterized its chemical and biological impact on the periprosthetic tissue obtained at revision surgery of a fractured titanium-alloy modular neck of a patient with hip osteoarthritis. We applied a combination of photon, electron and ion beam micro-spectroscopy techniques, including hybrid optical fluorescence and reflectance micro-spectroscopy, scanning electron microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), helium ion microscopy (HIM) and micro-particle-induced X-ray emission (micro-PIXE). Micron-sized wear debris were found as the main cause of the tissue oxidative stress exhibited through lipopigments accumulation in the nearby lysosome. This may explain the indications of chronic inflammation from prior histologic examination. Furthermore, insights on extensive fretting and corrosion of the debris on nm scale and a quantitative measure of significant Al and V release into the tissue together with hydroxyapatite-like layer formation particularly bound to the regions with the highest Al content were revealed. The functional and structural information obtained at molecular and subcellular level contributes to a better understanding of the macroscopic inflammatory processes observed in the tissue level. The established label-free correlative microscopy approach can efficiently be adopted to study any other clinical cases related to ALTR.

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Observed Tissue Reactions Associated with Subacute Implantation of Cortical Intraparenchymal Microelectrode Arrays

Stereotactic and Functional Neurosurgery ◽

10.1159/000517249 ◽

2021 ◽

pp. 1-3

Author(s):

Chengyuan Wu ◽

Ashwini D. Sharan ◽

Michael Kogan ◽

Robert H. Rosenwasser ◽

John Donoghue ◽

...

Keyword(s):

Microelectrode Arrays ◽

Tissue Reactions

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Effect of a Calcium-silicate-based Restorative Cement on Pulp Repair

Journal of Dental Research ◽

10.1177/0022034512460833 ◽

2012 ◽

Vol 91 (12) ◽

pp. 1166-1171 ◽

Cited By ~ 110

Author(s):

X.V. Tran ◽

C. Gorin ◽

C. Willig ◽

B. Baroukh ◽

B. Pellat ◽

...

Keyword(s):

Calcium Silicate ◽

Glass Ionomer Cement ◽

Repair Process ◽

Male Rats ◽

Time Points ◽

Tertiary Dentin ◽

Pulp Exposure ◽

Calcium Silicate Cements ◽

Reparative Process ◽

Dentin Formation

In cases of pulp injury, capping materials are used to enhance tertiary dentin formation; Ca(OH)2 and MTA are the current gold standards. The aim of this study was to evaluate the capacity of a new calcium-silicate-based restorative cement to induce pulp healing in a rat pulp injury model. For that purpose, cavities with mechanical pulp exposure were prepared on maxillary first molars of 27 six-week-old male rats, and damaged pulps were capped with either the new calcium-silicate-based restorative cement (Biodentine), MTA, or Ca(OH)2. Cavities were sealed with glass-ionomer cement, and the repair process was assessed at several time-points. At day 7, our results showed that both the evaluated cement and MTA induced cell proliferation and formation of mineralization foci, which were strongly positive for osteopontin. At longer time-points, we observed the formation of a homogeneous dentin bridge at the injury site, secreted by cells displaying an odontoblastic phenotype. In contrast, the reparative tissue induced by Ca(OH)2 showed porous organization, suggesting a reparative process different from those induced by calcium silicate cements. Analysis of these data suggests that the evaluated cement can be used for direct pulp-capping.

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In Vivo Analysis of the Biocompatibility and Bone Healing Capacity of a Novel Bone Grafting Material Combined with Hyaluronic Acid

International Journal of Molecular Sciences ◽

10.3390/ijms22094818 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4818

Author(s):

Annica Pröhl ◽

Milijana Batinic ◽

Said Alkildani ◽

Michael Hahn ◽

Milena Radenkovic ◽

...

Keyword(s):

Bone Substitute ◽

Sham Operation ◽

Bone Substitute Material ◽

Water Binding ◽

Sham Operation Group ◽

Operation Group ◽

Substitute Material ◽

Tissue Reactions ◽

Inflammatory Tissue

The present in vivo study analyses both the inflammatory tissue reactions and the bone healing capacity of a newly developed bone substitute material (BSM) based on xenogeneic bone substitute granules combined with hyaluronate (HY) as a water-binding molecule. The results of the hyaluronate containing bone substitute material (BSM) were compared to a control xenogeneic BSM of the same chemical composition and a sham operation group up to 16 weeks post implantationem. A major focus of the study was to analyze the residual hyaluronate and its effects on the material-dependent healing behavior and the inflammatory tissue responses. The study included 63 male Wistar rats using the calvaria implantation model for 2, 8, and 16 weeks post implantationem. Established and Good Laboratory Practice (GLP)-conforming histological, histopathological, and histomorphometrical analysis methods were conducted. The results showed that the new hyaluronate containing BSM was gradually integrated within newly formed bone up to the end of the study that ended in a condition of complete bone defect healing. Thereby, no differences to the healing capacity of the control BSM were found. However, the bone formation in both groups was continuously significantly higher compared to the sham operation group. Additionally, no differences in the (inflammatory) tissue response that was analyzed via qualitative and (semi-) quantitative methods were found. Interestingly, no differences were found between the numbers of pro- and anti-inflammatory macrophages between the three study groups over the entire course of the study. No signs of the HY as a water-binding part of the BSM were histologically detectable at any of the study time points, altogether the results of the present study show that HY allows for an optimal material-associated bone tissue healing comparable to the control xenogeneic BSM. The added HY seems to be degraded within a very short time period of less than 2 weeks so that the remaining BSM granules allow for a gradual osteoconductive bone regeneration. Additionally, no differences between the inflammatory tissue reactions in both material groups and the sham operation group were found. Thus, the new hyaluronate containing xenogeneic BSM and also the control BSM have been shown to be fully biocompatible without any differences regarding bone regeneration.

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Partial pulpotomy without age restriction: a retrospective assessment of permanent teeth with carious pulp exposure

Clinical Oral Investigations ◽

10.1007/s00784-021-04007-2 ◽

2021 ◽

Author(s):

Florin Eggmann ◽

Thomas J. W. Gasser ◽

Hanjo Hecker ◽

Mauro Amato ◽

Roland Weiger ◽

...

Keyword(s):

Survival Rates ◽

Age Groups ◽

Permanent Teeth ◽

Eligibility Criteria ◽

Presumptive Diagnosis ◽

Tooth Discoloration ◽

Significant Difference ◽

Pulp Exposure ◽

The Mean

Abstract Objectives This study aimed to retrospectively evaluate clinical and radiographic outcomes of partial pulpotomy performed in permanent teeth with carious pulp exposure. Materials and methods Records of patients undergoing treatment at an undergraduate dental clinic between 2010 and 2019 were screened for partial pulpotomies in teeth with a presumptive diagnosis of normal pulp or reversible pulpitis. The follow-up had to be ≥ 1 year. Patient data were retrieved and analyzed using Mantel-Cox chi square tests and Kaplan–Meier statistics. The level of significance was set at α = 0.05. Results Partial pulpotomy was performed in 111 cases, of which 64 (58%) fulfilled the eligibility criteria. At the time of partial pulpotomy, the mean age was 37.3 (± 13.5) years (age range 18–85). The mean observation period was 3.1 (± 2.0) years. Two early failures (3.1%) and five late failures (7.7%) were recorded. The overall success rate of maintaining pulp vitality was 89.1%, with 98.4% tooth survival. The cumulative pulp survival rates of partial pulpotomy in patients aged < 30 years, between 30 and 40 years, and > 40 years were 100%, 75.5%, and 90.5%, respectively, with no significant difference between the age groups (p = 0.225). At follow-up, narrowing of the pulp canal space and tooth discoloration were observed in 10.9% and 3.1% of cases, respectively. Conclusions Across age groups, partial pulpotomy achieved favorable short and medium-term outcomes in teeth with carious pulp exposure. Clinical relevance Adequate case selection provided, partial pulpotomy is a viable operative approach to treat permanent teeth with deep carious lesions irrespective of patients’ age.

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