Dental Hypotheses
Volume:12 Issue: 4, Oct-Dec 2021

Alzheimer disease is one of the most frequent neurodegenerative diseases. Porphyromonas gingivalis is the key pathogen of chronic periodontitis, and it has a virulence factor known as gingipain. Gingipain is a proteolytic enzyme capable of penetrating the blood–brain barrier to reach the brain’s center of cognition. Gingipain that reaches the brain is suspected of having a relationship with an amyloid-beta plaque and neurofibrillary tangle, which play a critical role in the formation of Alzheimer disease. These bacteria may also suppress the immune system by reducing cytokine tumor growth factor (TGF-beta) and Interferon (IFN-gamma) and imbalance of Th17/Treg (Regulatory T cells). Besides that, the involvement of P. gingivalis in the brain may trigger neuroinflammation and lead to neuron defect and worsen Alzheimer disease. This review aims to discuss the correlation between P. gingivalis and the development of Alzheimer disease.

Introduction: Limited jaw motion is a common complication after orthognathic surgeries that can negatively affect the patients’ quality of life, thus it is required to be properly treated. Regarding the growing interests in laser application in density, we aimed to evaluate the effects of 660nm LLLT on mandibular lateral movements after orthognathic surgery. Materials and Methods: Twelve candidates of bimaxillary orthognathic surgery were included in a split-mouth, triple-blind phase 1 trial. On 1, 4, and 7 days after the surgery, a 660-nm diode low-level laser was applied to one facial side of patients, whereas the other side was kept untreated as placebo. Then, rightward and leftward mandibular movements from the maxillary midline were measured in millimeters (mm) on 2, 7, and 14 after the surgery. The measurements were then compared between the study groups using ANCOVA analysis. Results: Despite the constant improvement in mandibular lateral movements in both study groups, the rightward mandibular movements in LLLT group were significantly better than in placebo group on second (3.9 versus 3.2 mm, P= 0.015), seventh (5.6 versus 4.2 mm, P=0.018), and 14th (7.1 versus 5.2 mm, P=0.005) days after the surgery. Also, the leftward mandibular movements in LLLT group were significantly better than in placebo group on second (3.7 versus 2.1 mm, P= 0.021), seventh (4.9 versus 2.9 mm, P=0.019), and 14th (6.7 versus 4.2 mm, P=0.002) days after the surgery. Conclusion: LLLT can effectively improve both rightward and leftward movements of mandibular after an orthognathic surgery.

The number of dental services provided is related to the type of services needed by a population and treatment decision making by dentists. This descriptive study aimed to compare the dental service mix in two different payment systems.

The dental records of a long-established dental clinic were reviewed. Treatment performed, during October 2018 and October 2019, by 36 dentists, 12 dentists worked in both payment method periods, 12 of them worked only in salary, and 12 of them worked in fee for service (FFS) period.

Preventive dental services and practices without treatment (visits, diagnostic radiography, and referrals) decreased, and practices included aggressive treatments (randomized controlled trial, extraction, and crown) and highly aggressive procedure (surgery) increased from salary to FFS period. The total activities of dentists were higher in FFS.

According to our results, in a salary system, the dentist was more likely to refer and perform preventive treatments, whereas in the FFS payment system, the dentists choose more aggressive treatments. Payment method may change dental service mix.

This study aimed to investigate the effect of G-Coat Plus (GCP) on the shear punch strength (SPS) of conventional glass ionomer cements (CGICs) and resin composites (RCs).

In this experimental study, four groups of restorative materials (two CGICs (Equia Forte Fil and Fuji Bulk), and two RCs (Aura Bulk fil and Filtek Z250) were used. Twenty specimens were prepared for each material. GCP was applied on the first subgroup (n= 10). The specimens were stored in distilled water at 37°C, and SPS values were measured after 24 hours. Two-way analysis of variance and independent t test were used for data analysis.

RCs showed significant higher SPS values compared to the CGICs (P < 0.001). All materials tested showed increased SPS values after applying GCP (P < 0.05).

Applying GCP significantly improves the SPS of tooth-colored restorative materials used in this study.

The aim of this study was to assess the detection of some hard- and soft-tissue cephalometric landmarks when using a thyroid lead shield.

Two study groups were designed, and each group consisted of 50 cephalograms: the first group was without thyroid shield cephalograms and the second group consisted of cephalograms taken using a lead thyroid shield. An observer blinded about the aim of the study was appointed to identify 12 landmarks on the lateral cephalograms.

Out of 12 of landmarks, 3 landmarks had a significant relationship with the thyroid shield group. Landmarks of cervical point, second and third vertebrae were not detected in 20%, 30%, and 66% of cases, respectively.

Two hard-tissue landmarks (second and third vertebrae) and one soft-tissue landmark (cervical point) were masked by the thyroid shield when preparing a cephalogram.

Passive smoker individuals whom live near the smokers and pigmentation appears on their oral mucosa due to proximity from smokers.

This study was carried-out on 50 patients suffering from pigmentation of the mouth that were collected from the private dental clinic were obtained and 50 individual’s neighbouring to them and considered as the passive smoking group.

For passive smoker the pigmentation increasing with duration of smoking, in non-filtered cigarettes than filtered cigarette and in heavy smokers than mild smokers The intraoral distribution of melanin pigmentations commonly observed in the buccal region, Lingual, gingival and palatal of the mouth.

Incorporation of calcium phosphate agents into fluoride varnishes might improve anticaries benefits. But when clinical results do not mirror this view, explanations remain unclear.

Our hypothesis is that better clinical outcomes are obtained from fluoride plus calcium phosphate varnishes when there is sustained, controlled release of mineralizing ions.

Calculations of ion activity products and putative mineral phases have been underutilized in assessing clinical outcomes of fluoride varnishes with calcium phosphate agents. In this study, a mineral phase comparison between a low-release varnish comprising functionalized tricalcium phosphate (fTCP) against a high-release varnish comprising casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) was made. These calculations revealed the predominance of hydroxyapatite, fluorapatite, and calcium fluoride formation for the varnish containing fTCP, whereas the varnish containing CPP-ACP produced the same minerals along with b-TCP and octacalcium phosphate. This hypothesis shows the mineral phases expected to form from fluoride plus calcium phosphate varnishes might bear on clinical outcomes.