Journal of Dentistry, Shiraz University of Medical Sciences
Volume:24 Issue: 4, Dec 2023

Statement of the Problem:

In recent years, the use of artificial intelligence (AI) has become increasingly popular in dentistry because it facilitates the process of diagnosis and clinical decision-making. However, AI holds multiple prominent drawbacks, which restrict its wide application today. It is necessary for dentists to be aware of AI's pros and cons before its implementation.

Therefore, the present study was conducted to comprehensively review various applications of AI in all dental branches along with its advantages and disadvantages.

For this review article, a complete query was carried out on PubMed and Google Scholar databases and the studies published during 2010-2022 were collected using the keywords "Artificial Intelligence”, "Dentistry," "Machine learning," "Deep learning," and "Diagnostic System." Ultimately, 116 relevant articles focused on artificial intelligence in dentistry were selected and evaluated.

In new research AI applications in detecting dental abnormalities and oral malignancies based on radiographic view and histopathological features, designing dental implants and crowns, determining tooth preparation finishing line, analyzing growth patterns, estimating biological age, predicting the viability of dental pulp stem cells, analyzing the gene expression of periapical lesions, forensic dentistry, and predicting the success rate of treatments, have been mentioned. Despite AI's benefits in clinical dentistry, three controversial challenges including ease of use, financial return on investment, and evidence of performance exist and need to be managed.

As evidenced by the obtained results, the most crucial progression of AI is in oral malignancies' diagnostic systems. However, AI's newest advancements in various branches of dentistry require further scientific work before being applied to clinical practice. Moreover, the immense use of AI in clinical dentistry is only achievable when its challenges are appropriately managed.

Statement of the Problem: 

Management of gag reflex is a challenging process during many dental treatments. Various studies have been carried out to evaluate different pharmacological and non-pharmacological techniques to control gagging.

The aim of this study is to review the available evidence on methods proposed for managing the gag reflex.

This systematic review adheres to the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. A comprehensive search was conducted in English and Persian based on articles published from 2015 to 2022 (February) in PubMed, Scopus, Science Direct, Web of Science, Google Scholar, ISC and SID. All studies were first screened based on their title and abstract. The quality assessment of articles was carried out by two independent authors. Then, risk of bias evaluation was conducted according to Cochrane parameters.

In total, 1704 studies were identified via search. After reviewing title and abstract, 16 studies found eligible based on inclusion and exclusion criteria. Following quality and risk of bias assessment, 9 studies included in the systematic review.

Based on the finding of this review, distraction techniques, nitrous oxide, and low-level laser therapy were found effective in management of gag reflex. The dentist should consider gag reflex management based on the type of dental treatment, gag severity, patient's age, and available capabilities.

Statement of the Problem: 

The common causes of obstructive sleep apnea (OSA) are identified as anatomic and/or functional abnormality in the oral cavity, oropharynx, velopharynx, and hypopharynx leading to compromised airway space and increased collapsibility.

This study was conducted to evaluate the effect of implant-supported mandibular complete denture in improving the airway space among completely edentulous patients with OSA and compare it with conventional complete denture.

In this observational study, completely edentulous individuals were screened with snoring, tiredness, observed apnea, high blood pressure, body mass index, age, neck circumference, and gender (STOP-Bang) questionnaire to evaluate the incidence of OSA. Ten mild-moderate patients were included as study participants. Lateral cephalograms (L1) made at the edentulous state was considered baseline. They were rehabilitated with complete denture prosthesis. One week after denture insertion, two implants were placed in the edentulous mandibular arch. Delayed loading protocol was followed. Lateral cephalogram (L2) was made 6 months after complete denture insertion and 6 months after implant-supported prosthesis (L3). Cephalometric tracings were used to evaluate change in upper airway space (UAS), middle airway space (MAS), and lower airway space (LAS). Repeated measures ANOVA was used to evaluate statistical significance in the airway measurements made at the three intervals. Post hoc Tukey HSD and Bonferroni test were used to assess if the differences obtained were truly significant.

Statistical analysis revealed significant differences in UAS, MAS and LAS between L1, L2 and L3 (p< 0.05). Post hoc Tukey HSD indicated that UAS increased significantly at all three intervals followed by LAS and MAS respectively (α=.05). Post hoc Bonferroni test indicated that implant-supported mandibular complete dentures had a significant improvement in airway space when compared to conventional complete dentures (α=.05).

Implant-supported mandibular complete denture could be effective in edentulous patients with mild-moderate OSA.

Statement of the Problem: 

Candida albicans (C. albicans) is recognized as the most common opportunistic pathogen in patients with an impaired immune system, and due to the frequent use of antifungal medicine, a variety of drug-resistant species are developing. Probiotics are a part of the human microbiome and natural competitors of Candida by producing lactic acid, low pH, and other secreted metabolites. The role of probiotics in preventing fungal infections has always been discussed.

This study aimed to investigate the antifungal effect of Lactobacillus casei (L. casei) on fluconazole- and amphotericin B-resistant C. albicans species isolated from the oral cavity of acute myeloid leukemia patients.

In this experimental study, eight strains of fluconazole- and amphotericin B-resistant C. albicans were used. The antifungal effects of probiotic L. casei and nystatin were measured by the co-aggregation method 1, 2, and 4 h after beginning the study. After each hour of exposure, C. albicans and L. casei colonies were counted.

L. casei had a significant ability to aggregate with both fluconazole- and amphotericin B-resistant C. albicans in all designated intervals, which increased with time. In the first hour of the study, no significant difference was observed between the effects of L. casei on the two drug-resistant strains. However, as time passed, it had a more significant antifungal effect on fluconazole, compared to amphotericin B resistant species (p Value<0.001). Cell counts showed that the number of fungal cells decreased significantly as time passed (p< 0.001).

L. casei had a significant ability to aggregate with both drug-resistant C. albicans species and showed higher antifungal activity on fluconazole-resistant than amphotericin B-resistant species.

Statement of the Problem: 

Early detection of caries and the extent of carious lesions for appropriate treatment planning are very important and lead to introduction of new diagnostic tools.

This study aimed to compare the diagnostic accuracy of VistaCam IX Proxi and bitewing radiography for detection of posterior interproximal caries.

This in vitro study was performed on 40 extracted posterior teeth without cavitated carious lesions. Bitewing radiographs were obtained, infrared (IR) examination was performed, and the teeth were sectioned for histopathological analysis under a stereomicroscope as the gold standard for detection of caries and determination of the extent of carious lesions. Data were analyzed with Cohen’s kappa statistic, and Wilcoxon rank sum test.

The specificity of VistaCam IX Proxi and bitewing radiography was 71.4% and 87.7%, respectively. Their sensitivity was 100% and 40% for enamel caries, 72.8% and 54.5% for external half dentin caries, and 82.3% and 58.8% for internal half dentin caries, respectively (p= 0.048).

Bitewing radiography had a higher specificity and lower rate of false positive results. However, VistaCam IX Proxi had higher sensitivity for caries detection with lower rate of false negative results. Considering the higher sensitivity and significantly lower frequency of false negative results by VistaCam IX Proxi, it may be reliably used for caries detection specially enamel caries, and can serve as an adjunct to bitewing radiography.

Statement of the Problem: 

Salivary gland tumors represent about 3% of the head and neck tumors. Pleomorphic adenoma (PA) is the most common benign salivary gland tumor.

This study was conducted to investigate and describe some clinical and histopathological aspects of salivary pleomorphic adenomas with special reference to the epithelial and mesenchymal components.

One hundred tissue samples diagnosed as PA were sourced from archival tissue blocks between 2009 and 2019 in this retrospective study. Some clinical and demographic features, including age, sex, tumor size, and tumor location were recorded. This study included only samples taken by excisional biopsy. Then, the samples were histologically classified into three subtypes according to the proportion of epithelial and stromal components. The demographic and clinicopathological variables were statistically analyzed using Chi-square test or Fisher’s exact test, considering a significance level of 5% (p< .05).

In the present study, most cases (61%) were found in females, representing a female–male ratio of 1.6:1. The peak incidence was seen in the 4th and 5th decades of life. In 87% of cases, PA occurred in major salivary glands. There was a significant difference between the age of the patient and squamous metaplasia (p= 0.036). There was also a significant difference between the size of tumor and the amount of myxoid stroma (p= 0.021). Extensive myxoid stroma was mostly seen in tumors larger than 3.37cm (p= 0.001). In addition, there was a statistically significant difference between capsular invasion and the development of squamous metaplasia (p= 0.001).

 In this study, there was a significant correlation between the gland type and capsular features and between the size of tumor and rate of squamous metaplasia. A detailed clinical and histopathological analysis of PAs may provide a better insight to the pathophysiology of the lesion, tumor cell differentiation, and prognostic factors.

Statement of the Problem: 

Some components of implant treatment are reusable. Therefore, possible changes during fixation, removal, and sterilization process should be tested. Many studies have examined the reuse of implant parts, but the impact of repeated use of scan bodies on the accuracy of implant position has not been well investigated.

The aim of this in vitro study was to compare the effect of repeated use of two different types of scan bodies on the accuracy of implant position.

In this in vitro experimental study, two acrylic resin maxillary models, each with two implant analogues inserted at the site of missing first and second molars were used. Two types of scan bodies including titanium and polyetheretherketone (PEEK) were used for digital impression. Then they were ten times removed and autoclaved for sterilization. The first scan was considered as a reference to be compared with the other next nine scans. Values of linear distance between two scan bodies, diameter changes of each scan body, and three-dimensional linear displacement (ΔR) were measured. These values were compared between the two types of scan bodies using t-test (α=.05). 

There was significant difference between titanium and PEEK scan bodies regarding inter-implant distance variation (p=.006) and diameter change (p< .001) in repeated use. However, for the ΔR, there was no significant difference between them (p= 0.759).

The results demonstrated that type of scan body could affect the accuracy of implant position transfer after repeated use. PEEK scan body performed better after 9 cycles of reuse in comparison with titanium scan body.

Statement of the Problem: 

The prevalence of non-carious dentin lesions is on the rise mainly due to improved life expectancy. Successful management of these lesions is often challenging, and given that dentin can be remineralized, adverse consequences due to progression of these lesions can be prevented or minimized as such.

This study aimed to assess the effect of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) and Remin-Pro remineralizing agents on dentin microhardness of non-carious dentin lesions.

This in vitro, experimental study evaluated 36 extracted sound human premolars. The teeth were decoronated at the cementoenamel junction. Enamel was removed, and dentin was exposed at the cervical third of the buccal surface. The primary microhardness of dentin was then measured. The teeth, standardized in terms of dentin microhardness, then underwent demineralization by acid etching and were subjected to microhardness test again. They were then randomized into three groups for treatment with CPP-ACP, Remin-Pro, and artificial saliva (control), and dentin microhardness was measured for the third time after treatment. Data were analyzed using ANOVA.

Within group comparisons showed a significant difference in microhardness at the three time points in all three groups (p< 0.005). Between-group comparisons revealed that the microhardness of the three groups was not significantly different at baseline or after demineralization. However, the microhardness of the three groups was significantly different after the intervention (p= 0.000). Pairwise comparisons revealed significantly higher microhardness in the CPP-ACP group than the other two groups (p= 0.003). Remin-Pro and the control groups were not significantly different in this respect (p= 0.340).

CPP-ACP can be used for remineralization of non-caries dentin lesions; however, Remin-Pro does not appear to be effective for this purpose.

Statement of the Problem: 

Bond strength of furcation repair materials is an essential factor in clinical success. Studies on the effect of adding titanium dioxide (TiO2) nanoparticles on the push-out bond strength of commonly used endodontic cements for furcation perforation repair is limited.

This study aimed to evaluate the effect of adding TiO2 nanoparticles to white Portland cement (PC), white mineral trioxide aggregate (MTA), and calcium enriched mixture cement (CEM) on their push-out bond strengths.

In this in vitro study, 120 endodontically treated molars were assigned to six groups (n=20) based on the material used to repair the perforation. In three groups, the cements (white PC, white MTA, and CEM) were placed in pure form, and in the three remaining groups, 1 weight % of TiO2 was added. The push-out bond strength was measured using a universal testing machine at a strain rate of 0.5 mm/min. Data were analyzed using one-way ANOVA and post hoc Games-Howell test (p< 0.05).

One-way ANOVA showed significant differences in the mean bond strength values between the six groups (p= 0.002). The post hoc Games-Howell test showed that the bond strengths in MTA+TiO2 and PC+TiO2 groups were significantly higher than those in MTA and PC groups, respectively. However, there was no significant difference in the bond strength between CEM and CEM+ TiO2 groups.

The incorporation of TiO2 into MTA and PC increased their push-out bond strength. However, it did not affect the push-out bond strength of CEM cement.

Statement of the Problem: 

Recent microbiological studies have expressed ever-increasing concerns about Candida albicans as a causal factor in the failure of endodontic treatments. Real-time quantitative polymerase chain reaction (qPCR), including the SYBR Green I system, is a technique in which a fluorescent dye is incorporated into the double-stranded DNA that is produced during DNA polymerase activity.

This study aimed to determine the relative prevalence of Candida albicans in root canals of retreatment cases and its association with endodontic symptoms.

In the present cross-sectional/analytical study fifty subjects were selected. Clinical features and radiographic status of the teeth were also evaluated. After access cavity preparation, the retrieved material and dentinal chips removed from the root canal were transferred into 1.5-mL microtubes, followed by storage at -20ºC until used for DNA extraction. A DNeasy Tissue Kit was used to extract DNA using the DNeasy protocol for animal tissues. Master Plus SYBR Green I (Jena Bioscience, Germany) was used in a Rotor-gene Real-time PCR System for real-time PCR. The relationship between the presence of Candida albicans and the clinical and radiographic features were analyzed using McNemar’s test.

There was a significant relationship between the radiographic findings in endodontically treated teeth and the presence of Candida albicans. However, there was no significant relationship between the presence of Candida albicans and any of the clinical symptoms.

In spite of the limitations of this study, we concluded that Candida albicans was associated with root canal infections in endodontic retreatment cases, but there was no relationship with the clinical symptoms.

Hybrid lesions of jaws are rare entities defined as two different lesions co-occurring in the same location, with identical histopathological origin. Ameloblastoma, calcifying cystic odontogenic tumor and odontoma are among the most common lesions that have been reported to combine with other lesions. In this study, a hybrid lesion of odontogenic keratocyst (OKC) and odontoma in the mandible of a forty-five years old male reported. Additional to the rarity of this hybrid lesion, the present case had unique radiologic features, including atypical location and extension of the lesion and profound knife-edge root resorption of the teeth in the area, which was not a common feature for any of the two lesions. The surgical procedure was marsupialization to reduce the size of the lesion. As a result of the surgery, the healing of the surgical wound was uneventful. In addition, careful follow-up for the patient was conducted, which had no recurrence till now (after 15 months).

Metastatic lesions of the jaws are a diagnostic challenge because of their scarcity and uncharacteristic clinical-radiographic features. Carcinoma of unknown primary origin (CUP) is characterized by the existence of metastatic disease with no recognized primary neoplasm after a comprehensive work-up. CUP shows a poor prognosis with limited treatment choices. This paper presents a 64-year-old male with a chief complaint of paresthesia of the chin and lower lip. Panoramic radiography showed an ill-defined radiolucency in the left mandibular molar area and the residue of the first molar root. Microscopic examination demonstrated features of mucin-producing adenocarcinoma and was not similar to common neoplasms of the jaw. The whole-body scan revealed multiple osseous uptakes. CDX2 was diffusely positive. However, in the end, the origin of the primary tumor was not determined. Considering the aforementioned data, the diagnosis of metastatic adenocarcinoma with unknown primary origin was made. CUP of the oral cavity is an extremely rare event. The possibility of metastasis should be raised in a patient who complains of paresthesia. Awareness of the clinical and histopathologic features of these malignancies is crucial for clinicians and pathologists to have a proper diagnosis.