Pulp sensitivity changes during orthodontic treatment at different time periods: a prospective study

Effect of laser corticotomy on canine retraction rate: a split-mouth randomized clinical trial

BACKGROUND

This study assessed the effect of corticotomy with Er: YAG (erbium-doped yttrium aluminium garnet) laser on the rate of canine retraction.

METHODS

This randomized split-mouth controlled clinical trial was conducted on 12 patients undergoing orthodontic treatment with extraction of maxillary first premolars. Following initial leveling and alignment, an alginate impression was made from the maxillary arch, and Er: YAG laser corticotomy was performed in one of the maxillary quadrants of each patient. Canine retraction was started immediately after corticotomy by placement of nickel-titanium (NiTi) closed coil springs at both sides. At the end of each month, alginate records were repeated for 4 months. Study models were scanned, and the anteroposterior movement of canine was quantified bilaterally. Pain was also measured by a visual analog scale (VAS). Probing depth (PPD) of canines and two adjacent teeth was also evaluated and pulp vitality was assessed by performing the cold test. Data were analyzed by paired and independent t-test and one-way ANOVA (alpha = 0.05).

RESULTS

The rate of canine retraction was significantly greater in the laser-assisted corticotomy quadrant than the control (P < 0.05). No significant difference existed in posterior anchorage loss, canine rotation angle, PPD, pulp vitality, or pain score between two groups (P > 0.05).

CONCLUSIONS

Flapless Er: YAG laser corticotomy significantly enhanced canine retraction rate with no adverse effect on other parameters.

Identification of the Ideal Reference Site and Pain Threshold Values for the Placement of Electric Pulp Testers in Permanent Upper and Lower Anterior Teeth: A Cross-Sectional Study

INTRODUCTION

Electric pulp testers (EPTs) are widely used diagnostic tools for diagnosing traumatized teeth. Several factors can affect the result of an electric pulp test. One such factor that will affect the diagnosis is the electrode tip placement. Hence, the current study aims to identify the most painful site and response time threshold in healthy anterior teeth.

METHODS

A total of 90 individuals, 48 male and 42 female, aged 19 to 25 years, were recruited. An EPT was placed on three different sites: the cervical, middle, and incisal third of the labial surface of both upper and lower anterior teeth (central incisor, lateral incisor, and canine) with an appropriate electrolyte as a conducting medium. Later, the threshold values were recorded, and pain assessment was done using the Memojis pain scale (MPS). Finally, the data was analyzed statistically using the Mann-Whitney U test.

RESULTS

Mean and standard deviation values of reaction time were collected from 540 EPT readings (three sites from 180 teeth). Among the three sites tested, the difference between the upper and lower central incisors was statistically insignificant (p > 0.05). Similarly, when upper and lower lateral incisors and canines were compared, a statistically significant difference was observed among the three sites (p<0.05). There was a significant difference (p<0.05) in the pain scores only on the incisal and cervical thirds of the upper and lower central incisors. Only the incisal third showed a statistically significant difference (p<0.05) between the pain scores in the upper and lateral incisors. At the same time, a statistically significant difference in the pain scores was observed among the three tested sites between the upper and lower canines (p<0.05).  Conclusion: Lower threshold values were appreciated at the incisal third of all the upper and lower anterior teeth for placing the EPT. Most individuals have experienced a score of 2 (hurts little bit) for the perceived pain using EPTs for both the upper and lower anterior teeth.

The association between orthodontic treatment and temporomandibular disorders diagnosis and disease characteristics

BACKGROUND

The association between orthodontic treatment and temporomandibular disorders (TMD) has been contentious in the literature.

OBJECTIVES

To analyse the associations between orthodontic treatment and TMD diagnosis and diseases characteristics.

METHODS

This case-control study included 291 individuals, 192 TMDs and 99 controls. All patients underwent assessment based on a questionnaire and a clinical examination according to Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Differences in orthodontic treatment between TMDs and controls, as well as across different TMD diagnoses within the TMD group were analysed. Patients who underwent orthodontic treatment were compared to those who did not, regarding their trauma history, bruxism, aggressive teeth brushing, level of oral hygiene, pain scores, muscle tenderness scores and subjective sleep quality.

RESULTS

Of the 291 participants, 119 (40.9%) underwent orthodontic treatment and 172 (59.1%) had no orthodontics experience. Orthodontic treatment included: mandibular orthodontic treatment (102 subjects) and maxillary orthodontic treatment (113 subjects) of those 47 used a headgear. Following multivariate analysis among TMDs, orthodontic treatment was associated with a good level of oral hygiene versus poor (Odds ratio [OR]: 5.17 [1.04-25.59]), lower number of tender muscles [OR = 0.84 (0.74-0.96)] and lower (better) Pittsburgh Sleep Quality Index (PSQI) scores (OR = 0.86 [0.76-0.97]). None of the studied parameters maintained a statistically significant association with orthodontic treatment in the multivariate analysis among the entire study population.

CONCLUSIONS

Utilising a holistic approach, this study supports the main hypothesis that orthodontic treatment is not associated with TMD diagnosis and disease characteristics.

The effect of orthodontic tooth movement on the sensitivity of dental pulp: A systematic review and meta-analysis

Objectives

Orthodontic tooth movement (OTM) is a process that's initiated by orthodontic forces. As a consequence, the forces could restrict pulpal blood supply, possibly affecting dental pulp. The study aimed to review the available evidence on the short and long-term effects of orthodontic tooth movement on dental pulp sensitivity and to identify clinically relevant risk factors.

Sources

PubMed, Embase, Scopus, and Web of Science were searched for papers from 1990 to the end of December 2021.

Study selection

The studies that evaluated dental pulp sensitivity of teeth undergoing OTM were included in the systematic review. Randomized, nonrandomized and case-controlled studies were included in the analysis. Risk of bias in each study was assessed using the ROBINS-I tool.

Data

The systematic search yielded an initial sample of 1110 studies, 17 were included in qualitative analysis. Most studies were classified as moderate risk of bias, however only limited long-term evidence with a higher risk of bias exists. Electric pulp test (EPT) sensitivity threshold during active OTM was increased by 4.25 SD (P < 0.001) and the relative risk (RR) of pulpal non-sensitivity was 13.27 (P < 0.001) higher compared to pre-orthodontic baseline status. Significant differences were between subgroups associated with the type of OTM. A positive relationship between pulpal non-sensitivity and mean patient age was discovered (P = 0.041). After OTM the risk of pulpal non-sensitivity remained 5.76 times higher (P < 0.001) in the long term.

Conclusions

Evidence showed that OTM could affect dental pulp sensitivity. The type of OTM and patients' age were identified as clinically relevant risk factors.

Clinical significance

Orthodontic tooth movement negatively impacts the sensitivity of dental pulp during active treatment and to a lesser degree in the long term. Pulpal sensitivity tests during active OTM should therefore be interpreted with caution. Data indicates younger patients have a lower risk of negative pulpal sensitivity during orthodontic treatment.

Age-Related Variation of Pulpal Oxygen Saturation in Healthy Primary and Permanent Teeth in Children: A Clinical Study

(1) Background: Pulse oximetry (PO) is an effective method of dental pulp status monitorization but still lacks practical implementation in dentistry, as well as clear reference values for different tooth types. The study’s aim was to investigate the age-related variation of blood oxygen saturation (SpO2) from the dental pulp during different stages of tooth development in all types of primary and permanent teeth of children. (2) Methods: The pulps of 600 healthy primary and permanent teeth (incisors, canines, premolars, and molars) of patients aged 2−15 years were tested with an adapted PO device, and the results were statistically analyzed; (3) Results: Statistically significant differences (p < 0.05) were found between open-apex and closed-apex teeth and between the canines and other tooth types in both primary and permanent dentitions. (4) Conclusions: Values of SpO2 tended to decrease with age progression in both primary and permanent dentitions. Enamel and dentine thickness and their optical properties and the shape and volume of coronal pulp, which differed among tooth types, seemed to have some influence on the reading as well. The study indicates that factors such as the root development and the tooth type must be taken into account when establishing reference SpO2 values for the dental pulp.