Comparison of Bone Morphogenic Proteins’ and Platelet Rich Fibrins’ Effectiveness in Socket Preservation

The dentist faces a difficult challenge in preserving the quantity and quality of gum and bone tissues. Furthermore, the processes adopted should meet these objectives while posing no substantial future issues. In current dental and maxillofacial surgery, a variety of materials as Morphogenic Protein of Bone (BMP) and Platelet Rich Fibrins (PRF) are employed to repair and reconstruct bone tissue. The purpose of this review was to compare the efficiency of both BMP’s and PRF’s in Socket preservation. Reviewing the literature was conducted by using the following search strategies: Bone Morphogenic Proteins, Platelet Rich Fibrins, socket preservation approach, comparison of BMPs and PRFs, Bone Morphogenic Proteins and effectiveness in socket preservation and Platelet Rich Fibrins’ effectiveness in socket preservation. In conclusion, BMPs have been studied more completely than PRFs, and they have higher impacts on hard tissue regeneration and repair, according to the research. The fact that PRFs increase soft tissue healing shows how promising they are. Especially when we consider that soft tissue healing is more important than socket care in implant dentistry.

Knowledge and Attitude towards Antibiotics Prescription and Antimicrobial Resistance among Dental Surgeons in Saudi Arabia

Aims: To assess knowledge and attitude towards antibiotics prescription and antimicrobial resistance among dentist in Saudi Arabia. Study Design:  Cross-sectional, survey-based study. Place and Duration of Study: Sample: Saudi Arabia, between June 2020 and October 2021. Methodology: This is was a cross-sectional, survey-based study in Saudi Arabia. Data was collected using a predesigned self-administered online questionnaire. The survey was distributed to dentist and dental surgeons in Saudi Arabia. It included demographic data, Knowledge about antibiotics, Attitude towards antibiotics, prescription of antibiotics based on the clinical situation. Data were analyzed by the SPSS program, version 25 at a level of significance of 0.05.  Results: A total of 208 study participants completed the survey questionnaire. The results showed that the half of study participants females. Moreover, more than half of the study participants were bachelor’s degree. Additionally, 21.2% of the study participants earned dental internship. However, the least proportion had the master’s degree or higher (4.3%).91.8% of the study respondents were general dentist compared to 2.9% were oral surgeon and the least portion 1% was endodontist. Conclusion: The use of antibiotics inappropriately was common, and the drivers of inappropriate practices were found as young age, male sex, higher education, and a negative attitude regarding antibiotic use.

Clinical assessment of oral dryness: development of a scoring system related to salivary flow and mucosal wetness

OBJECTIVE

The aim of this study was to develop a clinical oral dryness score (CODS) for routine use in assessment of xerostomia patients and determine its relationship with salivary flow rates and mucosal wetness.

STUDY DESIGN

CODS was determined from 10 features of oral dryness, each scoring as 1 point for a total score of 0-10. CODS, salivary flow rates, and mucosal wetness were measured in 100 patients and 50 healthy control subjects. The reproducibility of CODS was 0.89-0.96 (intraclass correlation coefficient).

RESULTS

The mean ± SD CODS in patients was 6.0 ± 1.6 compared with 1.0 ± 0.9 for control subjects (P < .001), and the highest mean value was in the primary Sjögren syndrome group. There was a general inverse relationship in patients between mean CODS and salivary flow rate (P < .01) and mean CODS and mucosal wetness (P < .01).

CONCLUSIONS

The CODS was found to be useful, easy to use, and reliable for routine assessment of the severity of dry mouth.

Altered plasticity of the parasympathetic innervation in the recovering rat submandibular gland following extensive atrophy

Adult rat submandibular glands have a rich autonomic innervation, with parasympathetic and sympathetic nerves working in synergy rather than antagonistically. Ligation of the secretory duct rapidly causes atrophy and the loss of most acini, which are the main target cell for parasympathetic nerves. Following deligation, there is a recovery of gland structure and function, as assessed by autonomimetic stimulation. This study examines whether the parasympathetic nerves reattach to new target cells to form functional neuro-effector junctions. Under recovery anaesthesia, the submandibular duct of adult male rats was ligated via an intra-oral approach to avoid damaging the chorda-lingual nerve. Four weeks later, rats were either killed or anaesthetized and the ligation clip removed. Following a further 8 weeks, both submandibular ducts were cannulated under terminal anaesthesia. Salivary flows were then stimulated electrically (chorda-lingual nerve at 2, 5 and 10 Hz) and subsequently by methacholine (whole-body infusion at two doses). Glands were excised, weighed and divided for further in vitro studies or fixed for histological examination. Ligation of ducts caused 75% loss of gland weight, with the loss of most acinar cells. Of the remaining acini, only 50% were innervated despite unchanged choline acetyltransferase activity, suggesting few parasympathetic nerves had died. Following deligation, submandibular glands recovered half their weight and had normal morphology. Salivary flows from both glands (per unit of gland tissue) were similar when evoked by methacholine but greater from the deligated glands when evoked by nerve stimulation. This suggests that parasympathetic nerves had reattached to new target cells in the recovered glands at a greater ratio than normal, confirming reinnervation of the regenerating gland.

Acute salivary gland hypofunction in the duct ligation model in the absence of inflammation

Objective

The commonly associated aetiology of salivary gland inflammation and salivary hypofunction has led to the widely held belief that inflammation causes salivary gland hypofunction. Indeed, our own recent study seemed to support this contention. Here, we tested the hypothesis that, in an acute duct ligation model, eliminating inflammation the submandibular gland would recover normal function.

Materials and methods

Ligation of the rat submandibular gland excretory duct for 24 h was used to induce inflammation and salivary gland hypofunction. A group of duct ligated rats was compared with a second group given dexamethasone, on the day of duct ligation. Twenty-four hours later salivary gland function was assessed and salivary glands were collected.

Results

Histology and myeloperoxidase activity assay revealed a profound decrease in inflammatory cell infiltration of ligated glands from rats given dexamethasone, compared with ligated glands in the absence of dexamethasone. Salivary flow rate evoked by methacholine was decreased (P < 0.01) by approximately 56% (ligated vs control, 79 ± 9 μl min⁻¹ g⁻¹vs 177 ± 11 μl min⁻¹ g⁻¹) and salivary flow from ligated dexamethasone-treated and ligated glands was similar.

Conclusion

Despite eliminating the inflammatory reaction in the ligated gland, salivary hypofunction was not reversed, suggesting that other mechanisms must be at work in the ligation-induced salivary hypofunction.

Rat salivary gland ligation causes reversible secretory hypofunction

AIM

To determine the influence of inflammation on salivary secretion. Secretion by salivary glands involves interactions between nerves, blood vessels and salivary cells. The present study investigated the effects of inflammation on rat submandibular gland function following acute ductal obstruction.

METHODS

Under recovery anaesthesia a metal clip was placed on the main duct of the submandibular gland. After 24 h salivary secretion was evoked by nerve and methacholine stimulation. For recovery experiments the clip was removed after 24 h and the animal left to recover for 3 days when salivary function was again assessed.

RESULTS

By 24 h of obstruction an inflammatory infiltrate had developed within the obstructed gland and stimulated salivary flows were just 20% of the normal secretion, whilst protein secretion and ion reabsorption were also severely impaired. If ductal obstruction was removed after 24 h the salivary function returned to normal after 3 days of recovery. In vitro analysis of cells from 24-h ligated glands revealed normal changes in intracellular calcium (the main secondary messenger involved in fluid secretion) in response to methacholine stimulation. Protein secretion from isolated cells indicated some changes in particular to methacholine-induced protein secretion although a significant protein secretion was still seen in response to isoprenaline - the main stimulus for protein secretion.

CONCLUSION

This report demonstrates reversible salivary inhibition associated with an inflammatory infiltrate within the salivary gland.

Recovery of rat submandibular salivary gland function following removal of obstruction: a sialometrical and sialochemical study

Functional recovery of the rat submandibular gland following ligation of the main excretory duct was examined. Rat submandibular glands were ligated for 1, 4 and 8 weeks using a micro-clip with a plastic tube. Micro-clips were removed and glands were allowed to recover for periods of 8, 16 and 24 weeks. Submandibular glands were stimulated with autonomimetic drugs (methacholine and isoprenaline) and salivas were collected from atrophic or de-ligated and contralateral control glands. Glands recovered almost full size (92% of control gland) following 24 weeks of de-ligation. Saliva volume secreted by ligated/de-ligated (RSM) and control (LSM) glands were similar with different doses of agonists. Protein output expressed per gram of tissue wet weight was similar from both ligated/de-ligated and control glands with all doses of agonist. Sodium and chloride levels were higher from de-ligated glands than contralateral control glands. Protein electrophoresis showed similar profiles of salivary proteins in all samples with some minor differences. Acinar cells in de-ligated glands showed a normal morphology, as indicated by light microscopy, whilst granular ductal cells were fewer and contained fewer secretory granules. Sodium potassium ATPase staining of striated ducts in de-ligated glands was similar to that of control glands. It can be concluded that rat submandibular glands can regenerate following severe atrophy and secrete normal amounts of saliva containing broadly a full profile of secretory proteins. In contrast to acinar cells, ductal cells appear not to recover full function.

Intraoral duct ligation without inclusion of the parasympathetic nerve supply induces rat submandibular gland atrophy

The atrophic effect of ligating the main duct of the right submandibular gland was examined in rat using a novel intraoral approach that did not include the chorda lingual (CL) nerve. Comparison was made with the effect of duct ligation including the attached CL nerve as carried out in previous studies. In all animals, the contralateral, unligated left submandibular gland was used as a control. At different times (1, 2, 7, 14 and 21 days) after ligation, glands were removed and weighed. Tissue was fixed for morphological analysis and homogenized for biochemical assay of secretory proteins. After 21 days, ligated glands showed a significant decrease in wet weight compared with unligated glands. Weight loss was the greatest (P < 0.05) in glands ligated with the CL nerve included. Light microscopy revealed that following ligation, an initial inflammatory reaction was followed by severe atrophy of acini and granular ducts. The atrophy was less severe when the CL nerve was not ligated. Secretory proteins were decreased from day 1 onwards following duct ligation in both groups. It can be concluded that most of the atrophy induced by duct ligation is independent of damage caused to the parasympathetic nerve supply, although the latter causes a greater atrophy presumably due to denervation.