Effect of orthodontic space closure on dental pulp sensitivity. Prospective clinical trial.

BACKGROUND: Orthodontic tooth movement (OTM) is a biological process that can influence the function of the pulp, including its innervation. The excitability of the nerve fibres of the pulp may be altered by forces exerted on the nerve fibres or by reduced blood flow to the pulp. The aim of this clinical study was to evaluate the sensitivity of the dental pulp during levelling and during the phase of space closure, to assess the role of certain controlled risk factors. METHODS: Twenty-two adolescent participants requiring orthodontic space closure in transcanine sector were enrolled in a prospective clinical study. Patients were observed before OTM, after levelling and 1 month during active space closure. The sensitivity threshold of the pulp was measured using the electric pulp test (EPT). Dental models were obtained using an intraoral scanner, allowing measurement of interdental distances and calculation of OTM speed. The teeth were categorized according to position and tooth type. RESULTS: The EPT values increased significantly during orthodontic treatment (one-way RM-ANOVA, P = .014). There was a significant difference in EPT values between the tooth categories. Teeth with a single root adjacent to the residual space had the highest EPT thresholds (two-way RM-ANOVA, P < .001; Holm-Sidak, P < .05). CONCLUSIONS: OTM reduced pulpal sensitivity. Pulpal sensitivity during active space closure was similar to sensitivity during the levelling phase. The pulpal sensitivity of molars was less affected by OTM than that of single-rooted teeth, while teeth closer to the gap had a significantly higher pulpal sensitivity threshold during active OTM.

Three-dimensional assessment of palatal area changes after posterior crossbite correction with tooth-borne and tooth bone-borne rapid maxillary expansion.

OBJECTIVES: To assess and compare the three-dimensional treatment changes in palatal surface area and volume using either tooth-borne (TB) or tooth bone-borne (TBB) rapid maxillary expanders and to evaluate the long-term effects of the two devices and the incidence of the relapse between the groups. MATERIALS AND METHODS: A total of 52 consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years (standard deviation [SD], 1.3), or the TBB group, mean age 9.5 years (SD, 1.2). Study casts were taken before, directly after, 1 year after, and 5 years after expansion. Study casts were digitized, superimposed, and evaluated. Participants were randomly allocated in blocks of different sizes using the concealed allocation principle in a 1:1 ratio. RESULTS: Changes in palatal volume, palatal surface area, and palatal projection area within and between the groups up to 5 years after expansion followed the same pattern and did not show any statistically significant differences between the groups. Relapse was seen in 15% of the patients. It seemed that open-bite and a Class III growth pattern could be assumed as prognosis-deteriorating factors in regard to stability of the treatment. CONCLUSIONS: There were no significant differences between the TB and TBB groups in palatal volume, palatal shell area, or palatal projection area directly after expansion or at 1 year and 5 years after expansion, which implies that the two devices gave rise to the same immediate and long-term outcomes.

Comparison of the vitality tests used in the dental clinical practice and histological analysis of the dental pulp.

In dentistry, indirect diagnostic methods such as electrical sensibility testing and pulse oximetry are used to assess the status of the pulp. Our study aimed to determine the correlation between hemoglobin oxygen saturation and vascular volume density (Vvasc). We also wanted to examine an electrical sensibility test and the volume density of myelinated nerve fibers (Vnerv). Twenty-six intact permanent premolars were included in the study. For histological analysis, the pulp tissue was stained with hematoxylin-eosin and immunohistochemically for von Willebrand factor and S100 to detect blood vessels and myelinated nerve fibers, respectively. The stereological analysis was used to determine the Vvasc and Vnerv. Statistical analysis was done using the Pearson correlation test and Welch's ANOVA test. Histological analysis showed that the pulp tissue was strongly vascularized and innervated. A significant positive correlation was found between Vvasc and hemoglobin oxygen saturation levels (p=0.030). A significant negative correlation was found between Vnerv and the lowest electrical voltage that patient felt (p=0.033). According to the maturity of the dental apex, teeth were divided into a group with open (N=6, OA group) and closed apex (N=20, CA group). We found that pulps in the CA group had higher Vnerv than the OA group (p=0.037). In contrast, there were no significant differences in Vvasc of the pulp tissue (p=0.059), oxygen saturation (p=0.907), or electrical voltage (p=0.113) between both groups. We can conclude that the measurement of pulse oximetry and electrical sensibility test reflect the morphology of healthy pulp tissue independently of the maturity of the dental apex.

Effects of low-level light therapy on xerostomia related to hyposalivation: a systematic review and meta-analysis of clinical trials.

Hyposalivation is a condition represented by a reduced salivary flow and may include symptoms such as mouth dryness (xerostomia), loss of taste, pain, dysphagia, and dysphonia, all of which greatly affect an individual's quality of life.The aim of the present study was to systematically review the effects of low-level light therapy irradiation (photobiomodulation) on salivary gland function in patients with hyposalivation.The main question of the systematic review was: "Does low-level light irradiation therapy of the salivary glands affect salivary flow rate or indicators of salivary function (ion and protein concentrations) in patients with xerostomia or hyposalivation?" The question was based on the PICO (participant, intervention, control, outcome) principle and followed the PRISMA guidelines. Databases were explored and papers published between the years 1997 and 2020 were reviewed for the following Mesh-term keywords and their corresponding entry terms in different combinations: "Low-level light therapy," "Xerostomia," "Saliva," "Salivary glands," "Salivation."The initial sample consisted of 220 articles. Of those, 47 articles were used for full-text analysis and 18 were used for a systematic review, 14 were used in meta-analysis. According to their individual quality, most articles were classified as high quality of evidence according to the GRADE score. Meta-analysis of the evidence observed increase of unstimulated salivary flow 0.51 SMD compared to placebo (95% CI: 0.16-0.86), I2 = 50%, p = 0.005.The findings of our review revealed evidence of a beneficial effect of photobiomodulation therapy on salivary gland function. The therapy alleviates xerostomia and hyposalivation. However, these effects are reported short term only and did not induce lasting effects of photobiomodulation therapy on patients' quality of life.

The impact of photobiomodulation of major salivary glands on caries risk.

Dental caries is a complex multifactorial chronic infectious disease guided by several risk or protective factors. Saliva has an important role in caries and the remineralization process. Caries risk assessment is defined as the probability of new caries lesion development or the existing lesion progression in a given time period. Caries diagnostics and risk factor assessment are followed by targeted elimination of risk factors and less conservative but abundant preventive therapeutic measures. The aim of our prospective randomized study was to elucidate on how photobiomodulation of major salivary glands with polychromatic light or LED light affects caries risk factors in high caries-risk patients. Thirty-six patients were assigned to one of the following three experimental groups: the first, irradiated with polarized polychromatic light (40 mW/cm2, wavelengths 480-3400 nm); the second, a continuous LED light (16 mW/cm2, wavelengths 625, 660, 850 nm); the third, same LED light in a pulsed mode. The fourth group was the control, for which a non-therapeutic visible light was used. Light was administered extra-orally bilaterally above the parotid and submandibular glands for 10 min and intra-orally above the sublingual glands for 5 min, 3 times a week, for 4 consecutive weeks. Each patient's caries risk was assessed according to Cariogram before and after therapy. Caries risk factors were determined from samples of saliva before therapy, two weeks after it commenced, at the end of therapy, and four weeks after the end of therapy. At the end of treatment, the following findings were obtained: In the group irradiated with polarized polychromatic light and in the group irradiated with continuous LED light, the Streptococcus mutans and Lactobacillus counts decreased and salivary buffering capacity increased (p < 0.05). In the group irradiated with pulsed LED light, Streptococcus mutans counts decreased and unstimulated salivary flow and salivary buffering capacity increased (p < 0.05). In all three experimental groups, caries risk was lower (p < 0.05). In the placebo control group, there were no statistically significant differences between parameters before and after therapy. We concluded that photobiomodulation of major salivary glands in high caries-risk patients can reduce the cariogenic bacteria in saliva and improve some salivary parameters, thus reducing caries risk.

Three-dimensional evaluation of forced unilateral posterior crossbite correction in the mixed dentition: a randomized controlled trial.

OBJECTIVES: The objectives of this study were to assess the three-dimensional (3D) treatment changes (palatal surface area and volume) of forced unilateral posterior crossbite correction using either quad-helix or removable expansion plate appliances in the mixed dentition, and to compare the treatment changes with the three-dimensional changes occurring in age-matched untreated unilateral posterior crossbite patients as well as in subjects with normal occlusion and with no or mild orthodontic treatment need. TRIAL DESIGN: Six-arm parallel group multicentre randomized controlled trial. MATERIALS AND METHODS: One-hundred and thirty-five patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 25, and the patients were randomized into the following five groups: quad-helix treatments in specialist orthodontic clinics (QHS), quad-helix treatments in general dentistry (QHG), removable expansion plate treatments in specialist orthodontic clinics (EPS), removable expansion plate treatments in general dentistry (EPG), and untreated crossbite (UC). Twenty-five patients with normal occlusion who served as normal controls were also included in the trial. Blinding of the outcome assessor and data analyst was accomplished. Data on all children were evaluated on an intention-to-treat basis, regarding 3D palatal surface area, palatal projection area, and palatal shell volume; two-dimensional linear measurements were registered at the same time. RESULTS: After treatment, the surface and projection area and shell volume increased in the four treatment groups (QHS, QHG, EPS, and EPG). QHS increased significantly more than EPG for the surface and projection area. The QHS and EPS had significantly higher mean difference for shell volume. LIMITATIONS: The trial considers a short-term evaluation. CONCLUSION: After treatment, there were no significant differences between the four treatment groups and the normal group, which implies that the surface and projection area together with the shell volume for the four treatment groups and the normal group were equivalent. TRIAL REGISTRATION: The trial was registered with https://www.researchweb.org/is/sverige, registration number: 220751.