Ricky Wk Wong

The inhibitory effects of naringin on the growth of periodontal pathogens in vitro

Naringin is a flavonoid that is commonly found in grapefruits. The objective of this study was to evaluate the effects of naringin on the growth of periodontal pathogens such as A. actinomycetemcomitans and P. gingivalis in vitro. For comparison, the effects of naringin on several oral microbes were also studied.

A comparison of pain experienced by patients treated with labial and lingual orthodontic appliances

SUMMARYnThe aim of this prospective longitudinal study was to compare pain experiences among Chinese adult patients treated with labial and lingual orthodontic appliances. Sixty patients, 30 with labial appliances (18 females and 12 males, mean age 20.33 years, SD +/- 4.205) and 30 with lingual appliances (22 females and 8 males, mean age 21.63 years, SD +/- 2.236), rated their overall pain experience on a 100 mm visual analogue scale (VAS) at three time points: 1 week (T(1)), 1 month (T(2)), and 3 months (T(3)) after bracket placement. In addition, on a separate 100 mm VAS, they rated their pain experience at the locations of the tongue, lips, cheeks, gums, face, and jaw at T(1), T(2), and T(3). Changes in pain VAS were conducted using Friedman analysis of variance, area under the curve (AUC) analysis and the data were compared using a t-test. There was no significant difference in global ratings of pain among those treated with labial or lingual appliances (P > 0.05). Among both groups, global ratings of pain decreased over the study period (P < 0.001). Patients treated with lingual appliances reported higher ratings of tongue pain (P < 0.001), while those treated with labial appliances reported higher ratings of lip (P < 0.001) and cheek (P < 0.001) pain. The findings indicate that patients treated with labial and lingual appliances rate similarly the level of overall pain they experience during treatment. Ratings of overall pain experienced decreased for both treatment groups with time. However, ratings of pain differed at various sites with respect to the type of orthodontic appliance. These findings have implications in informing patients treatment decision-making processes regarding labial and lingual appliances and in the management of discomfort associated with different treatment modalities.

Chinese red yeast rice (Monascus purpureus-fermented rice) promotes bone formation

BackgroundStatin can induce the gene expression of bone morphogenetic protein-2. Red yeast rice (RYR, Hongqu), i.e. rice fermented with Monascus purpureus, contains a natural form of statin. This study demonstrates the effects of RYR extract on bone formation.MethodsBone defects were created in the parietal bones of two New Zealand white rabbits. In the test animal, two defects were grafted with collagen matrix mixed with RYR extract. In the control animal, two defects were grafted with collagen matrix alone. UMR 106 cell line was used to test RYR extract in vitro. In the control group, cells were cultured for three durations (24 hours, 48 hours and 72 hours) without any intervention. In the RYR group, cells were cultured for the same durations with various concentrations of RYR extract (0.001 g/ml, 0.005 g/ml and 0.01 g/ml). Bicinchoninic acid (BCA) assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and alkaline phosphatase (ALP) assay were performed to measure total protein, mitochondrial activity and bone cell formation respectively.ResultsThe test animal showed more formation of new bone in the defects than the control animal. RYR significantly increased the optical density in the MTT assay and ALP activity in vitro.ConclusionRYR extract stimulated new bone formation in bone defects in vivo and increased bone cell formation in vitro.

Inhibitory effect of quercetin on periodontal pathogens in vitro

Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) are bacteria strongly associated with early onset, progressive and refractory periodontal disease and associated alveolar bone loss. Quercetin is a flavonoid found in many foods including apples, onions and tea. The aim of this study was to evaluate the effect of quercetin on in vitro growth of periodontal pathogens Aa and Pg. For comparison, quercetins effect on several oral microbes was also evaluated.

Resveratrol inhibits periodontal pathogens in vitro

The gram‐negative anaerobic bacteria A. actinomycetemcomitans (Aa) and P. gingivalis (Pg) are key components in the aetiology of periodontal disease, and associated hard‐tissue destruction. Resveratrol is a phytoalexin, produced naturally by several plants when under attack by bacterial or fungal pathogens. It is found in many foods including mulberries, peanuts and the skin of labrusca and muscadine grapes. The objective of this study was to evaluate the effect of resveratrol on the in vitro growth of periodontal pathogens Aa and Pg. For comparison, resveratrols effect on a variety of other oral microorganisms was also evaluated. Resveratrol demonstrates a poor solubility in water, thus different concentrations of resveratrol in the solvent dimethyl sulphoxide (DMSO) were added to calibrated suspensions of Aa and Pg. As a control, a parallel series of dilutions containing the vehicle DMSO alone was made to measure the effect of the solvent. Minimum inhibitory concentrations of the periodontal pathogens were calculated. All suspensions were incubated for 1, 3, 6 and 24u2009h in an anaerobic chamber at 37u2009°C. At each time interval, selected dilutions from each culture broth were plated on blood agar plates. Colonies appearing on blood agar plates were visually counted at 3u2009days for Aa, and at 5u2009days for Pg. The periodontal bacteria showed a significant decrease (pu2009<u20090.05) in viable counts after 1u2009h, whilst no colony forming units could be observed after 24u2009h. The results suggest that resveratrol possesses significant antimicrobial properties on periodontal pathogens in vitro. Copyright

Natural compounds containing mouthrinses in the management of dental plaque and gingivitis: a systematic review

ObjectivesTo evaluate the effectiveness of natural compounds containing mouthrinse (NCCM) as an adjunct to unsupervised oral hygiene in the management of dental plaque and gingivitis.Materials and methodsAn electronic search for clinical studies of NCCMs was conducted in Medline-PubMed, the Cochrane Central Register of Controlled Trials and EMBASE for a period spanning from the earliest available date in each database up to February 2013. Plaque index, gingival index, and gingival bleeding index were selected as primary outcomes. The methodological quality of the studies was assessed according to the “Levels of Evidence” outlined by the Center of Evidence-Based Medicine, and to the Jadad scale.ResultsThe screen yielded 2,236 titles and abstracts that met the inclusion criteria. These identified 11 clinical trials testing 13 different NCCMs, and were used for data extraction. Heterogeneity and the limited number of studies on any individual NCCM precluded a formal meta-analysis. Of the 13 NCCMs tested, eight demonstrated positive results, and few reported any adverse effects or events.ConclusionsEvidence proving the effectiveness of NCCM as an adjunct to unsupervised oral hygiene for plaque and gingivitis control is still insufficient. However, some natural products (compounds) may have oral health benefits, so further high-quality study is warranted.Clinical relevanceThis review provides an overview of the strength of clinical evidence regarding the effectiveness of natural compounds containing mouthrinses in promoting gingival health.

The effect of naringin on early growth and development of the spheno-occipital synchondrosis as measured by the expression of PTHrP and Sox9—an in vitro model

The aim of this study was to assess the effect of the flavonoid naringin on the growth of the spheno-occipital synchondrosis by quantifying the levels of expression of Sox9 and PTHrP in an in vitro mouse model. Fifty 1-day-old BALB/c mice were randomly assigned to experimental or control groups, and each group equally divided into five time frames (6, 24, 48, 72 and 168 hours). The mice were sacrificed with phenobarbitone sodium, and the spheno-occipital synchondroses dissected and cultured in control or experimental medium, with the experimental medium supplemented with 0.1 µm naringin. Sections of the specimens underwent immunohistochemical staining for Sox9 and PTHrP, and the amount of expression was quantified using true-colour RGB (red-green-blue) computer-assisted image-analysing system with digital imaging. Data analysis showed there was a significant increase of expression of Sox9 at 6 and 24 hours (P < 0.001) between experimental and control groups, however, there was no significant difference between the levels of expression of PTHrP between experimental and control groups at any of the time frames. There was a very weak correlation found in this study between the expression of PTHrP and Sox9. In conclusion, naringin enhances the growth of the spheno-occipital synchondrosis through over expression of Sox9. This is a successful in vitro model to study factors regulating the growth of the spheno-occipital synchondrosis.

Diagnosis and management of root resorption by erupting canines using cone-beam computed tomography and fixed palatal appliance: a case report

IntroductionResorption of the root of the maxillary incisors during ectopic eruption of the maxillary canines is not an uncommon phenomenon, and must be considered in all patients with seriously diverging eruption of the maxillary canines.Case presentationWe report on the diagnosis and treatment of a 10-year-old Chinese boy with severe crowding and risk of root resorptions caused by impacted canines in the upper arch and reverse overjet. With the aid of cone-beam computed tomography, the upper right canine crown of our patient was positioned in close proximity to the right lateral incisor while the left canine crown was hitting the root apex of the left lateral incisor. To avoid any progress of root resorption, use of an upper fixed palatal appliance with torquing spring to move the root of lateral incisors away from the canines, plus extraction of upper primary first molars, was selected as an interceptive treatment.ConclusionsCareful planning is crucial to avoid any complication through orthodontic treatment and to reduce the treatment time and cost.

Repair of a defect following the removal of an impacted maxillary canine by orthodontic tooth movement: a case report

This case report describes a 13-year-old boy with alveolar bony defect resulted from surgical removal of impacted upper canine transposed in the anterior region. The boy had a normal occlusion with malposition of upper central and lateral incisors. The treatment objectives were to align teeth, close spaces by mesial movement of the buccal segments in the upper jaw to repair bone loss. Fixed appliance with palatal root torque was used for the mesial movements, levelling, and alignment of teeth.Orthodontic tooth movement consisted of a sequence of root movement in a direction to increase the thickness of the labial cortical plate of bone, could ensure healthier periodontium. A healthier periodontium prior to space closure ensured repair of alveolar bony defect after surgical intervention. Orthodontic tooth movement should be added to our armamentarium for the repair of alveolar bony defect.

Self correction of anterior crossbite: a case report

A 9-year-old Chinese boy presented with an anterior crossbite, no treatment was performed at that time because the incisors have open root apices. The crossbite self-corrected after one year. This case demonstrated that an anterior crossbite may self-correct without treatment.