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While definitive evidence awaits, cannabis is emerging as a likely risk factor for periodontal tissue destruction. The mechanisms that underlie potential cannabis-induced or cannabis-enhanced periodontal diseases, however, remain to be elucidated. Herein, we 1) examine insights obtained from the endocannabinoid system, 2) summarize animal models of exposure to cannabinoid receptor agonists and antagonists, 3) review the evidence suggesting that cannabis and cannabis-derived molecules exert a profound influence on components of the oral microbiome, and 4) assess studies indicating that marijuana and phytocannabinoids compromise the immune response to plaque. Furthermore, we address how knowledge of cannabinoid influences in the oral cavity may be exploited to provide potential novel periodontal therapeutics, while recognizing that such medicinal approaches may be most appropriate for nonhabitual marijuana users. The suspected increase in susceptibility to periodontitis in marijuana users is multifaceted, and it is clear that we are only beginning to understand the complex toxicological, cellular, and microbial interactions involved. With marijuana consumption increasing across all societal demographics, periodontal complications of use may represent a significant, growing oral health concern. In preparation, an enhanced research response would seem appropriate.

The objective of this study was to assess clinical measurements related to the effectiveness of bisphosphonate (BP) administration as a supplement to conventional dental treatment in patients free of bone-related diseases using a network meta-analysis. Only randomized controlled trials (RCTs) were included that provided dental clinical measurements on human patients treated with BPs with or without similar untreated controls or treated with placebo. Information sources included a systematic search of 17 electronic databases up to August 2020, complemented by manual searches. Risk of bias assessment was performed with the revised Cochrane risk of bias tool for randomized trials (RoB 2.0). Extracted measurements were pooled according to time of evaluation. The random-effects model by DerSimonian and Laird was used to calculate mean differences (MDs) and the respective 95% confidence intervals (CIs). Seven RCTs were included in the network meta-analysis, assessing 391 subjects reporting on periodontal treatment effects after 2 to 12 mo of BP administration. BP treatment was associated with significant improvement of most clinical measurements, compared with BP-naive controls. According to the network ranking, alendronate was more efficient in improvement of probing depth and clinical attachment gain when compared to zoledronate or alendronate/risedronate. Similarly, the local application of alendronate as a gel was more effective than the oral administration. A long-term analysis of the pharmaceutical effects was not possible due to insufficient data. The current review, performed according to existing guidelines, included only RCTs and, through appropriate statistical analyses, provided precise estimates for most assessed outcomes. However, no adverse effects or long-term treatment results were analyzed due to inadequate pertinent data. BP administration seems to be beneficial in the short term for the treatment of periodontal diseases, mainly through controlling periodontal inflammation.

Oxidative stress is associated with age-related reactions. The anti-oxidative effects of a reduced form of co-enzyme Q10 (rCoQ10) suppress oxidative stress, which may contribute to the prevention of age-related inflammatory reactions. We examined the effects of topically applied rCoQ10 on periodontal inflammatory reactions in a rat aging model. Male Fischer 344 rats, 2 (n = 6) and 4 mos (n = 18) of age, were used. All of the two-month-old rats and 6 of the four-month-old rats were sacrificed and 12 remaining four-month-old rats received topically applied ointment with or without 1% rCoQ10 on the gingival surface until they reached 6 mos of age. The rats showed an age-dependent increase in circulating oxidative stress. RCoQ10 decreased oxidative DNA damage and tartrate-resistant acid-phosphatase-positive osteoclasts in the periodontal tissue at 6 mos of age as compared with the control. The same conditions lowered gene expression of caspase-1 and interleukin-1β in the periodontal tissue. Furthermore, Nod-like receptor protein 3 inflammasomes were less activated in periodontal tissues from rCoQ10-treated rats as compared with the control rats. Our results suggest that rCoQ10 suppresses age-related inflammatory reactions and osteoclast differentiation by inhibiting oxidative stress.

Periodontitis is an inflammatory disease that causes loss of the tooth-supporting apparatus, including periodontal ligament, cementum, and alveolar bone. A broad range of treatment options is currently available to restore the structure and function of the periodontal tissues. A regenerative approach, among others, is now considered the most promising paradigm for this purpose, harnessing the unique properties of stem cells. How to make full use of the body’s innate regenerative capacity is thus a key issue. While stem cells and bioactive factors are essential components in the regenerative processes, matrices play pivotal roles in recapitulating stem cell functions and potentiating therapeutic actions of bioactive molecules. Moreover, the positions of appropriate bioactive matrices relative to the injury site may stimulate the innate regenerative stem cell populations, removing the need to deliver cells that have been manipulated outside of the body. In this topical review, we update views on advanced designs of biomatrices—including mimicking of the native extracellular matrix, providing mechanical stimulation, activating cell-driven matrices, and delivering bioactive factors in a controllable manner—which are ultimately useful for the regenerative therapy of periodontal tissues.

Glass ionomers have been used for perforation repair and retrograde filling where biointegration with periodontal tissue is required. Collagen has been demonstrated to promote cellular adhesion and enhance mineral tissue compressive strength. It was hypothesized that an appropriate concentration of collagen integrated into glass ionomer may improve both bio-compatibility and the mechanical properties of the material. By SEM and AFM, we discovered 70-nm granules appearing on the surfaces of glass-ionomer/collagen hybrids. Acid-etching revealed irregularly shaped particles interlinked by membrane-like sheets on the surface of the material with the typical 70-nm granules. WST-1 assay showed that acid-etching significantly enhanced the viability of attached gingival fibroblasts. However, the glass-ionomer/collagen hybrids’ combined surface-etching outperformed other groups. The glass-ionomer/collagen hybrids presented enhanced compressive strength when integrated with 0.01% collagen, while higher concentrations of collagen compromised their mechanical property. In summary, collagen improved both the mechanical and biocompatible properties of glass ionomers. Further in vivo study is warranted.

Human gingival fluid contains a low-molecular-weight factor (10,000 to 25,000) which enhances the proliferation of murine thymocytes in the presence of suboptimal doses of mitogen. Although the gingival fluid has no Interleukin 2 (T cell growth factor) activity, as indicated by its inability to induce proliferation of an IL 2 dependent lymphocytic cell line, it is directly mitogenic for dermal fibroblasts. These studies suggest that the thymocyte and fibroblast growth-promoting properties of human gingival fluid may have important functions in regulating inflammatory responses in the human periodontal tissues.

Cyclic adenosine 3',5'-monophosphate (cAMY) concentrations and cellular distribution were studied in dental and periodontal tissues during tooth eruption in kittens. Although the mean levels of cAMP around developing teeth were similar in all the tissue samples, there were marked differences in cAMP stainability of tissues apical and occlusal to the erupting teeth.

Collagenase is produced by both epithelial and connective tissue cells of the human gingiva. Collagenase action was shown through viscometry, acrylamide gel electrophoresis, and electron microscopy. Collagen is cleaved into one-quarter and three-quarter pieces by collagenase derived from human gingiva.

The phenomenon of leukopedesis in gingival and periodontal tissues was measured by counting the number of orogranulocytes migrating into the mouth during repeated intervals of 30 seconds. Measurements were carried out with a computerized electronic cell grading system and classified as a non-subjective laboratory routine for indexing oral inflammation. For orogranulocytic migratory rate (OMR) readings above 1.2 X 106/30 sec, a minimum of three determinations is required for reliability. Single readings suffice for OMR's below 0.5 X 106/30 sec, which indicates that the system is suitable for mass screening purposes.

Collagen is the predominant organic constituent of bone, cementum, periodontal membranes, and gingiva. For this reason, it is the major protein destroyed during the course of periodontal diseases. Although for many years degradation of collagen has been known to occur as part of the process of periodontitis, demonstration of specific collagenase, derived from periodontal tissues and capable of acting at physiologic pH and ionic strength, has been recent.1-6 Discovery of the enzyme required the use of a tissue culture system. Previous investigators searching for collagenase in vertebrate tissues had examined homogenates without success.7'8

SYNOPSIS IN INTERLINGUA ACTIVITATE DE SYNTHASE DE CITRATO IN Tissu PERIODONTAL.—Con le utilisation del sensibile e convenibile essayo a fissura per ester thiolic, le activitate de synthase de citrato (EC 4.1.3.7; oxaloacetato-lyase de citrato) esseva determinate in le fractiones supematante de gingiva, osso alveolar, e altere tissus de porco de India. Cortice de femore, osso alveolar, gingiva, hepate, e ren possedeva approximativemente 1/60, 1/33, 1/24, 1/12, e 1/4, respectivemente, le activitate medie per mg de extrahite proteina cardiac. Le activitate exprimite a base de unitates de peso de tissu humide esseva etiam le plus alte pro le corde. Illo de osso alveolar e de gingiva esseva approximativemente 1/440 e 1/40, respectivemente, del correspondente valor trovate pro le corde.

The response of the periodontal membrane to reimplanted teeth carrying amalgam restorations in the middle third of their roots was studied from seven days to six months after grafting. The study revealed that the amalgam restorations produced an initial localized inflammation in the periodontal tissues that subsided subsequently with the formation of a pseudocapsule.

The purpose of this study was to evaluate the histologic response after replantation of mature, developed teeth without endodontic treatment in monkeys. To serve as experimental controls, the other replanted teeth received endodontic treatment. No significant differences were noted in the rate and quality of periodontal tissues healing between the endodontically and the nonendodontically treated teeth in monkeys sacrificed at 5, 7, and 14 days, and at 1, 2, and 3 months after replantation. However, specimens obtained at 4, 6, 9, and 12 months showed that teeth replanted without endodontics developed periapical complications, whereas endodontically treated teeth did not.

Basal growth in the rat incisor is controlled by occlusal restraint. The result of these two antagonistic forces is eruption, which is mediated via the periodontal ligament. The amount of eruption depends on the relation between the quality of the periodontal tissues and the amount of occlusal interference. If eruption does not rise above a certain minimum, odontogenesis proceeds abnormally.

Periodontal tissues and oral hygiene conditions of 75 inhabitants of an inland Alaskan village population were studied. Living habits had changed considerably since dental examinations and dietary studies were done eight years previously. Periodontal disease was severe and followed the same pattern as that in other populations, except that the influence of age alone was not so pronounced.

Pulp and whole teeth were transplanted between two histoincompatible strains of rats. A bimodal distribution of antibodies occurred. Hemagglutination titers stimulated by teeth were greater than those stimulated by pulp. The peaks probably represent IgM and IgG antibodies. Periodontal tissues may be more antigenic than pulp.

Low-protein-fed rats demonstrated lower levels of proliferative activity in non-injured periodontal tissues than was noted in ad-libitum-fed or pair-fed rats. Gingival wounding resulted in tissue compensation, at the site of injury, for the reduction in proliferative activity present in low-protein-fed young adult rats.

A study was undertaken to find a standard method that would be relatively reproducible and would visualize the vascular changes in hard and soft tissues that accompany pathologic changes. Each tooth and its surroundings were found to have a complex vascular network that is directed to its particular function. Also each network is closely connected with other vascular networks; they form a complex blood supply source which, when necessary, can easily provide a compensatory blood supply.