Healing Process of Autogenous Bone Graft in Spontaneously Hypertensive Rats Treated With Losartan: An Immunohistochemical and Histomorphometric Study

Do antihypertensive medications have an effect on dental implants? A systematic review

PURPOSE

The purpose of this systematic review was to compare the clinical outcomes of dental implants in users of antihypertensive medication with those of nonusers.

METHODS

This systematic review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and was registered in the International Prospective Register of Systematic Reviews under the number CRD42022319336. The electronic databases Medline (PubMed) and Central Cochrane were searched for relevant scientific literature published in English through May 2022. The focused question was, "Do patients taking antihypertensive medications have a similar impact on the clinical outcome and survival of dental implants compared with nonusers?".

RESULTS

A total of 49 articles were found, of which 3 articles were finally selected for a qualitative synthesis. The three studies included 959 patients. In all three studies, the commonly used medication was renin-angiotensin system (RAS) inhibitors. Two studies mentioned implant survival rate, which was 99.4% in antihypertensive medication users and 96.1% in the nonusers. One study found a higher implant stability quotient (ISQ) in patients taking antihypertensive medication (75.7 ± 5.9) compared with patients not taking antihypertensive medication (73.7 ± 8.1).

CONCLUSIONS

The limited available evidence showed that patient taking antihypertensive medications had comparable success rate and implant stability to patients not taking medications. The studies included patients taking different antihypertensive medications, so a drug-specific conclusion regarding the clinical outcome of dental implants is not possible. Further studies are needed, including patients taking certain antihypertensive medications, to determine their effects on dental implants.

Efficacy of mesenchymal stem cell-based therapy on the bone repair of hypertensive rats

OBJECTIVE

Hypertension disrupts the bone integrity and its repair ability. This study explores the efficiency of a therapy based on the application of mesenchymal stem cells (MSCs) to repair bone defects of spontaneously hypertensive rats (SHR).

METHODS

First, we evaluated SHR in terms of bone morphometry and differentiation of MSCs into osteoblasts. Then, the effects of the interactions between MSCs from normotensive rats (NTR-MSCs) cocultured with SHR (SHR-MSCs) on the osteoblast differentiation of both cell populations were evaluated. Also, bone formation into calvarial defects of SHR treated with NTR-MSCs was analyzed.

RESULTS

Hypertension induced bone loss evidenced by reduced bone morphometric parameters of femurs of SHR compared with NTR as well as decreased osteoblast differentiation of SHR-MSCs compared with NTR-MSCs. NTR-MSCs partially restored the capacity of SHR-MSCs to differentiate into osteoblasts, while SHR-MSCs exhibited a slight negative effect on NTR-MSCs. An enhanced bone repair was observed in defects treated with NTR-MSCs compared with control, stressing this cell therapy efficacy even in bones damaged by hypertension.

CONCLUSION

The use of MSCs derived from a heathy environment can be in the near future a smart approach to treat bone loss in the context of regenerative dentistry for oral rehabilitation of hypertensive patients.

The preventive effect of medicinal herbal extract and gelatin sponge on alveolar osteitis: An in vivo micro-computed tomography and immunohistochemical analysis in rats

OBJECTIVE

The purpose of this study was to evaluate the preventive effect of medicinal herbal extract (MHE) and gelatin sponge on alveolar osteitis (AO) in an experimental rat model.

DESIGN

Twenty-one Sprague-Dawley male rats with a mean age of 12 weeks were used. After extraction of the maxillary right first molar, an AO model was created for each animal. The animals were randomly separated to three equal groups. Group I served as a control, Group II was subjected to an intra-alveolar MHE application, and gelatin sponge was left in the sockets of Group III. On the 7th post-extraction day, the animals were sacrificed. The specimens were analyzed by micro-computed tomography (micro-CT), histopathologically and immunohistochemically.

RESULTS

Macroscopic evaluation revealed mild to intense signs of AO in all groups, but the difference was not significant (p < 0.05). Micro-CT analysis showed that bone formation was the highest in Group III (bone volume/total volume; 10.63 ± 4.9 %), whereas bone mineral density was the highest in Group I (2.05 ± 0.2 g/cm³). The difference was not significant (p > 0.05). In Group III, only 16.7 % of specimens showed no signal of inflammatory response (p < 0.01). The difference was not significant between the positive labeling for receptor activator of nuclear kappa-β (RANK), receptor activator of nuclear kappa-β ligand (RANKL), osteoprotegerin and osteopontin, but the intensity of Groups II and III was higher than the Group I for osteopontin (p < 0.01).

CONCLUSIONS

MHE and gelatin sponge were not effective enough to prevent alveolar osteitis, but positive results were obtained in bone healing.

Losartan improves alveolar bone dynamics in normotensive rats but not in hypertensive rats

Hypertension is one of the main causes of premature death in the world; also, it is associated with several bone alterations. Preclinical studies have demonstrated delayed alveolar bone healing in hypertensive rats. However, losartan has been favorable for consolidation of bone grafts and reduction in active periodontitis. Therefore, losartan is suggested to be effective in bone formation stages, as well as in the synthesis of matrix proteins and mineralization.

Alveolar bone healing in rats: micro-CT, immunohistochemical and molecular analysis

INTRODUCTION

Alveolar bone healing after upper incisor extraction in rats is a classical model of preclinical studies. The underlying morphometric, cellular and molecular mechanism, however, remains imprecise in a unique study.

OBJECTIVES

The aim of this study was therefore to characterize the alveolar bone healing after upper incisor extraction in rats by micro computed tomographic (Micro-CT), immunohistochemical and real-time polymerase chain reaction (RT-PCR) analysis.

MATERIAL AND METHODS

Thirty animals (Rattus norvegicus, Albinus Wistar) were divided into three groups after upper incisors extraction at 7, 14, and 28 days. Micro-CT was evaluated based on the morphometric parameters. Subsequently, the histological analyses and immunostaining of osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL) and tartrate resistant acid phosphate (TRAP) was performed. In addition, RT-PCR analyses of OPG, RANKL, the runt-related transcription factor 2 (RUNX2), osteocalcin (OC), osteopontin (OPN), osterix (OST) and receptor activator of nuclear kappa B (RANK) were performed to determine the expression of these proteins in the alveolar bone healing.

RESULTS

Micro-CT: The morphometric parameters of bone volume and trabecular thickness progressively increased over time. Consequently, a gradual decrease in trabecular separation, trabecular space and total bone porosity was observed. Immunohistochemical: There were no differences statistically significant between the positive labeling for OPG, RANKL and TRAP in the different periods. RT-PCR: At 28 days, there was a significant increase in OPG expression, while RANKL expression and the RANKL/OPG ratio both decreased over time.

CONCLUSION

Micro-CT showed the newly formed bone had favorable morphometric characteristics of quality and quantity. Beyond the RUNX2, OC, OPN, OST, and RANK proteins expressed in the alveolar bone healing, OPG and RANKL activity showed to be essential for activation of basic multicellular units during the alveolar bone healing.

Factors affecting the periapical healing process of endodontically treated teeth

Tissue repair is an essential process that reestablishes tissue integrity and regular function. Nevertheless, different therapeutic factors and clinical conditions may interfere in this process of periapical healing. This review aims to discuss the important therapeutic factors associated with the clinical protocol used during root canal treatment and to highlight the systemic conditions associated with the periapical healing process of endodontically treated teeth. The antibacterial strategies indicated in the conventional treatment of an inflamed and infected pulp and the modulation of the host's immune response may assist in tissue repair, if wound healing has been hindered by infection. Systemic conditions, such as diabetes mellitus and hypertension, can also inhibit wound healing. The success of root canal treatment is affected by the correct choice of clinical protocol. These factors are dependent on the sanitization process (instrumentation, irrigant solution, irrigating strategies, and intracanal dressing), the apical limit of the root canal preparation and obturation, and the quality of the sealer. The challenges affecting the healing process of endodontically treated teeth include control of the inflammation of pulp or infectious processes and simultaneous neutralization of unpredictable provocations to the periapical tissue. Along with these factors, one must understand the local and general clinical conditions (systemic health of the patient) that affect the outcome of root canal treatment prediction.

Extensive Surgical Procedures Result in Better Treatment Outcomes for Bisphosphonate-Related Osteonecrosis of the Jaw in Patients With Osteoporosis

PURPOSE

To identify the risk factors associated with relapse or treatment failure after surgery for bisphosphonate-related osteonecrosis of the jaw (BRONJ) in patients with osteoporosis.

PATIENTS AND METHODS

We performed a retrospective cohort study of BRONJ in patients with osteoporosis who had undergone surgical procedures from 2004 to 2016 at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. The predictor variables were a set of heterogeneous variables, including demographic (age, gender), anatomic (maxilla or mandible, or both, affected location), clinical (disease stage, etiology, comorbidities, history of intravenous bisphosphonate intake), time (conservative treatment before surgery, bisphosphonate treatment before the development of BRONJ, discontinuation of the drug before surgery, interval to final follow-up, interval to reoperation in the case of relapse or treatment failure), and perioperative variables (type of anesthesia, type of surgical procedures). The primary outcome variable was relapse after surgery that required reoperation (yes vs no). The descriptive and bivariate statistics were computed to assess the relationships between the study variables and the outcome. To determine the risk factors, we conducted a survival analysis using the Cox model.

RESULTS

The final sample included 325 subjects with a median age of 75 years, and 97% were women. After surgery, 30% of patients did not completely recuperate and underwent repeat surgery. The interval from the first surgery to reoperation ranged from 10 days to 5.6 years. Relapse or treatment failure most often occurred immediately after surgery. The type of surgical procedure and mode of anesthesia were the most important factors in the treatment outcome. A drug holiday did not appear to influence the likelihood of relapse after surgery.

CONCLUSIONS

Treatment of BRONJ in patients with osteoporosis might benefit from more careful and extensive surgical procedures rather than curettage performed with the patient under local anesthesia.