Pulpal blood flow changes due to rapid maxillary expansion

Effect of Orthognathic Surgery On Pulp Blood Flow and Pulp Sensibility: A Prospective Control Trial

INTRODUCTION

Orthognathic surgery has the potential to compromise the vitality of the teeth. This paper aims to assess changes in pulp blood flow (PBF) and pulp sensibility (PS) of the anterior dentition following orthognathic surgery and to assess the influence of the proximity of the surgical osteotomy on the PBF and/or PS.

METHODS

Twenty-six patients undergoing orthognathic surgery (Le Fort I or bilateral sagittal split osteotomy [BSSO]) were compared to sixteen control patients treated by fixed appliances only using Laser Doppler flowmeter (LDF) and thermal testing (CO2 snow). Surgery patients were tested at T1 (presurgery), T2 (4-5 weeks postsurgery), T3 (3 months postsurgery), and T4 (6 months postsurgery). Control patients were tested at T1 (pretreatment), T2 (6 months posttreatment), T3 (12 months posttreatment), and T4 (18 months posttreatment). Differences between the maxilla and mandible were assessed.

RESULTS

No differences in PBF or PS were recorded in the control group. In the surgery group, both jaws followed the same pattern after surgery, an initial decrease at T2 followed by a gradual recovery to pretreatment PBF levels with no significant difference between T1 versus T4 in both jaws. No difference in PBF was observed between the maxilla and mandible at any testing time interval.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PBF and PS of the anterior dentition was severely affected immediately postsurgery, followed by a gradual increase to full recovery. This pattern of recovery was exhibited in both jaws. A negative sensibility response or discoloration should not be seen as an indication of irreversible ischemic pulp changes. Monitoring for at least 6 months or using LDF as a confirmatory test is required before any irreversible endodontic treatment is to be considered.

The impact of mini-implant hybrid hyrax maxillary expansion on pulp blood flow and sensibility in healthy and traumatized teeth: A prospective study

INTRODUCTION

We aimed to assess pulp blood flow (PBF) and pulp sensibility changes in healthy and traumatized teeth undergoing maxillary expansion with a mini-implant hybrid hyrax appliance.

METHODS

Forty-five patients requiring maxillary expansion either with mini-implant supported hyrax expander (MARME) or tooth-borne hyrax expander (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (carbon dioxide snow). The study cohort was divided into 4 groups on the basis of expansion appliance (MARME or RME) and trauma experience (trauma or nontrauma). Each patient was tested before expansion, 2 weeks after expansion, and 3 months after expansion (T3). Relationships between PBF, time interval, and trauma were evaluated using linear mixed modeling.

RESULTS

Healthy teeth with RME or MARME expansion had reestablished pretreatment PBF at T3 (P >0.05). Traumatized teeth undergoing RME did not reach pretreatment PBF at T3 (P ≤0.05). There were no statistically significant changes in PBF in the MARME+Trauma group at all time intervals (P >0.05). A reduction in pulp blood flow occurred during rapid maxillary expansion from both expansion appliances; however, the relative reduction of PBF in MARME was less than with RME (P ≤0.05) 2 weeks after expansion. Most teeth across all groups (≥85%) maintained pulp sensibility at all time intervals regardless of whether there was a history of trauma.

CONCLUSIONS

Patients with transverse discrepancies and a history of trauma may benefit from MARME as evidenced by reduced changes in PBF compared with RME without affecting pulp sensibility.

Pain Reduction during Rapid Palatal Expansion Due to LED Photobiomodulation Irradiation: A Randomized Clinical Trial

Objective: The purpose of this research is to assess the analgesic efficiency of Photobiomodulation (PBM) in pain reduction in young patients during rapid maxillary expansion therapy. Materials and Methods: Thirty patients were included and allocated to an experimental group [Rapid Palatal Expansion (RPE) and PBM] and a control group (RPE only) at random. Inclusion criteria were skeletal age from CVS1 to CVS3, examined on the cephalometric lateral teleradiography, with cervical vertebra staging and completed eruption of upper first molar. Exclusion criteria were previous orthodontic treatment, bone disease, disability, or skeletal age from CVS4. Patients referred the pain they felt using a Numerical scale rate (NRS), ranging from 0 to 10, with specific intervals of time: 6 h, 12 h, 24 h, and from days 2 to 7. The Wilcoxon-Mann-Whitney test was used to evaluate differences in NRS reported values between the two groups. Results: The final sample included 30 patients, 14 males and 16 females, with a mean age of 7.8 ± 1.2 years. The pain that was felt at each time interval and the maximum score of pain were significantly lower in the experimental group (p < 0.05) and decreased faster in the experimental group, with a score test near to 0 after 2/3 days. Conclusions: PBM is efficient in reducing the intensity and the time of pain felt by young patients that undergo rapid maxillary expansion.

Pulp changes from rapid maxillary expansion: A systematic review

INTRODUCTION

This study aimed to systematically review the current evidence on the occurrence of pulp changes as side effects from orthopaedic rapid maxillary expansion (ORME) or surgically assisted rapid maxillary expansion (SARME).

METHODS

An electronic search was performed in eleven databases. The eligibility criteria included clinical studies assessing vitality, sensibility or dimensions of the pulp chamber of permanent teeth before and after ORME or SARME, without restrictions on publication year or language. The risk of bias was analysed with the NIH 'Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group' and the 'JBI for quasi-experimental studies' tool. The GRADE tool was used to assess the certainty of evidence.

RESULTS

The initial search resulted in 1,197 records, from which only seven before-after studies were included. There was a change in the pulpal blood flow (PBF) of maxillary incisors and canines up to 5 days after SARME, which gradually returned after 7 days to 3 months. After ORME, one study observed an increased PBF and one study observed a reduced PBF, which gradually returned after the end of expansion. Two studies observed that both ORME and SARME caused temporary changes in pulp sensibility. Three studies observed a significant reduction in the pulp chamber after ORME or SARME. The outcomes presented a very low certainty of evidence.

CONCLUSIONS

Although limited, the evidence shows that ORME and SARME caused temporary changes in pulp vitality and sensibility, with the possibility of inducing a reduction in pulp chamber dimensions.

Do orthodontic tooth movements induce pulp necrosis? A systematic review

BACKGROUND

Orthodontic tooth movements are performed by applying forces on teeth, which may cause alterations within the dental pulp. Previously published systematic reviews on the subject only included a small number of studies that assessed pulp status through reliable diagnostic methods. Since then, new evidence has been published, and a further systematic review on the subject is necessary.

OBJECTIVES

To evaluate whether there is scientific evidence to support the possibility that orthodontic tooth movements could induce pulp necrosis.

METHODS

A systematic search of articles published until June 2020 was performed using MeSH and free terms in the PubMed, Cochrane Library, LILACS, SciELO, Web of Science, EMBASE, Open Grey and Grey Literature databases. Randomized clinical trials (RCTs), nonrandomized clinical trials (nRCTs) and longitudinal (prospective or retrospective) studies that evaluated the pulp status of teeth subjected to orthodontic movements using laser Doppler flowmetry or pulse oximetry were included. The revised Cochrane risk of bias tools for randomized trials (RoB 2) and nonrandomized interventions (ROBINS-I) were used to assess the quality of the included studies. Relevant findings were summarized and evaluated. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool.

RESULTS

Initial screening of databases resulted in 353 studies. In total, 285 studies were excluded because they were duplicates. Of 68 eligible papers, fourteen met the inclusion criteria and were selected for full-text reading. Two studies were excluded due to the methods used to evaluate pulp status. Twelve studies (five RCTs, one nRCT and six prospective) were included. Four RCTs were classified as having an unclear risk of bias and one as having a high risk of bias. The nRCT was classified as having a low risk of bias. Two prospective studies were classified as having a moderate risk of bias and four as having a serious risk of bias. The GRADE analysis demonstrated a low to very low quality of evidence.

DISCUSSION

Significant limitations regarding the randomization processes within the included RCTs and a lack of control of confounders on most nonrandomized and longitudinal studies were verified.

CONCLUSIONS

This systematic review indicates that orthodontic movements do not induce loss of pulp vitality with low to very low certainty of evidence.

Evaluation of pulp cavity/chamber changes after tooth-borne and bone-borne rapid maxillary expansions: a CBCT study using surface-based superimposition and deviation analysis

OBJECTIVES

To compare volume and shape changes of pulp chamber of maxillary posterior teeth between tooth-borne and bone-borne maxillary expansions in adolescents.

MATERIALS AND METHODS

This study included 36 adolescents with bilateral maxillary crossbite who received tooth-borne rapid maxillary expansion (TB group, average age 14.4 years) or bone-borne rapid maxillary expansion (BB group, average age 14.7 years). Cone beam computed tomography (CBCT) was taken before treatment (T1) and after a 6-month retention period (T2). Volumetric and shape changes of pulp chamber of maxillary first molars and premolars were detected by referring to a specific 3D digital technology involving deviation analysis of T1/T2 CBCT-derived models of pulp chamber. Student's t tests were used to (1) compare T1 and T2 volumes of pulp chambers in TB and BB groups and (2) assess differences between the two groups in the post-treatment volumetric changes and in the percentage of matching of 3D pulp models.

RESULTS

All investigated teeth showed a reduction of pulp volume, being this difference significant in both TB (p < 0.0001) and BB (p < 0.0001) groups. The volumetric reduction was greater in the TB group; also, subjects in the TB group showed a lower percentage of matching between T1 and T2 pulp models (p < 0.0001). The area most affected by shape change was that of pulp horns.

CONCLUSIONS

TB expander could induce a higher volumetric reduction of pulp chamber of posterior teeth compared with BB expander, in the short term.

CLINICAL RELEVANCE

The present findings add new information concerning the effects of RME protocols on pulp tissue.

Pulp blood flow and sensibility in patients with a history of dental trauma undergoing maxillary expansion

OBJECTIVES

To assess changes in pulp blood flow (PBF) and pulp sensibility (PS) in teeth of patients with a history of dental trauma undergoing maxillary expansion.

MATERIALS AND METHODS

Twenty-five patients requiring rapid maxillary expansion (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (CO2 snow). Each patient was tested at T1 (prior to expansion), T2 (2 weeks after rapid expansion), and T3 (3 months after expansion). Relationships between PBF, time interval, and history of trauma were evaluated using linear mixed modelling.

RESULTS

Within the Trauma group, PBF was significantly lower (P ≤ .05) at T2 and T3 in comparison to T1 and significantly lower (P ≤ .05) at T2 in comparison to T3. In the Non-trauma group, PBF at T2 was significantly lower (P ≤ .05) than PBF at T1 and T3; however, no significant difference (P > .05) in PBF was observed when comparing PBF at T1 and T3. In both groups, PS was maintained in almost all teeth (>90%).

CONCLUSIONS

RME in healthy teeth causes reduction of PBF before reestablishment of pretreatment values. RME in traumatized teeth causes reduction of PBF without PBF being reestablished to pretreatment levels. Teeth with a history of compromise may have reduced adaptive capacity under insults such as RME, which should be appreciated during the informed consent process.

Changes in pulp blood flow and pulp sensibility resulting from surgically assisted rapid maxillary expansion: A clinical study

INTRODUCTION

The aim of this work was to assess and compare changes in pulp blood flow (PBF) and pulp sensibility (PS) after surgically assisted rapid maxillary expansion (SARME) and rapid orthopedic maxillary expansion (OME).

METHODS

Ten patients requiring SARME and 10 requiring OME had the pulp status of their maxillary incisors and canines assessed with the use of laser Doppler flowmetry, electric pulp testing (EPT), and CO₂ snow. The SARME group was assessed at T1-S (before surgery), T2-S (after surgery, before expansion), T3-S (after surgery, at completion of expansion), and T4-S (3 months after surgery). The OME group was assessed at T1-O (before expansion), T2-O (after rapid expansion), and T3-O (3 months after expansion commencement). Relationships between PBF/PS and the procedures, assessment times, and tooth types were evaluated.

RESULTS

In the SARME group, surgery did not cause significant (P ≥0.05) reduction in PBF, maxillary expansion did cause significant (P ≤0.05) reduction in PBF, pretreatment PBF was reestablished by T4-S, and nonresponses to both EPT and CO₂ peaked at T2-S. In the OME group, rapid expansion caused significant (P ≤0.05) reduction in PBF, pretreatment PBF was reestablished by T3-O, and all teeth responded to at least 1 of EPT or CO₂ at each assessment time.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Within the study's limitations, it can be concluded that both SARME and OME induce reduction but not elimination of PBF to maxillary anterior teeth and therefore do not cause loss of pulp vitality; surgery for SARME does not significantly reduce PBF to maxillary anterior teeth, rather it is the process of maxillary expansion that significantly reduces PBF in SARME patients; and caution when using CO₂ and EPT tests alone to assess pulp status after SARME is warranted because the capacity for CO₂ or EPT to provide negative sensibility responses despite the presence of PBF was observed.

[Vitality loss: influence of orthodontic process]

Vitality loss is an unusual event that can occur before, during or after an orthodontic treatment. It can lead to loss of sensitivity, color change or necrosis of the pulp tissue. Before starting the orthodontic treatment, we have to identify the tooth's risk (injured tooth, included occlusal trauma...). Knowing that, if an endodontic treatment has to be done, it is better to do it before starting orthodontic forces. Lamps do not provide problems except high intensity halogen ones. RPE on children, Le Fort I and mandibular osteotomies, corticotomies, genioplasties are responsible of a transitory ischemia without reaching a pathogen level. Mini-screws or mini-plates may be iatrogenic, if they impact the root. The repair options depend on the delay before removing the miniscrew and the nature of injured tissue.

Effect of extracorporeal shockwave therapy (ESWT) on pulpal blood flow after orthodontic treatment: a randomized clinical trial

OBJECTIVES

The effect of non-invasive extracorporeal shockwaves on pulpal blood flow in orthodontic patients who have undergone active treatment was investigated.

MATERIALS AND METHODS

Seventy-two adult patients were enrolled in the clinical trial and allocated by block randomization to a treatment or a placebo group at a 1:1 ratio. The patients were required to be otherwise healthy. Blinding was performed for the subjects and the outcome assessor. The region of interest was the mandibular incisors and canines, which were vital, unrestored, and had experienced no trauma. The active treatment group received a single shockwave treatment with 1000 impulses at 0.19-0.23 mJ/mm(2) while the placebo group was treated with a deactivated shockwave applicator but acoustic sham. Pulpal blood flow was evaluated four times over a period of 6 months starting from the day of bracket removal, using a laser Doppler device.

RESULTS

Thirty patients were evaluated in each group. Orthodontic patients who have undergone active treatment tend to have high levels of pulpal blood flow which decrease over a period of 6 months. Pulpal blood flow did not differ significantly over 6 months between the placebo and treatment group. Shockwave treatment was associated with no significant effect in respect of tooth type, age, sex, or mean blood pressure, and had no unintended pernicious effects.

CONCLUSIONS

Extracorporeal shockwaves had no statistically significant effect on pulpal blood flow. Multiple applications of ESWT in a pathological setup may be needed in future studies to demonstrate significant differences.

CLINICAL RELEVANCE

The absence of any adverse effects justifies further principal investigations of the use of shockwave treatment in the oral cavity.

Influence of orthodontic forces on human dental pulp: a systematic review

AIM

The aim of the present study was to systematically review the influence of orthodontic force on human dental pulp.

METHODS AND RESULTS

The addressed focused question was "Do orthodontic forces affect the human dental pulp?" which was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a specific question was constructed according to the PICO (Participants, Interventions, Control, Outcomes) principle. Databases were explored from 1952 up to and including August 2014 using different combinations of the following keywords: "orthodontic force"; "dental pulp"; "reaction" and "tooth movement". Literature reviews, letters to the editor, commentaries and case-reports were excluded. Thirty studies were included. Six studies assessed the effect of orthodontic forces on pulpal blood flow and 20 studies investigated the pulpal cellular responses to orthodontic forces. In 4 studies, pulpal responses to orthodontic forces were compared between previously traumatized- and non-traumatized teeth.

CONCLUSIONS

There is insufficient scientific validation regarding the association between orthodontic forces and human dental pulp. However, a history of dental trauma maybe considered a risk factor for loss of pulp vitality during orthodontic treatment.

Doppler flowmetry as a tool of predictive, preventive and personalised dentistry

Periodontal lesions are considered a major problem in the global burden of oral diseases due to their high frequency and negative impact on quality of life. Periodontal inflammation is accomplished by a breakdown of microcirculatory function. Early detection of gingival microvessel dysfunction helps diagnose and prevent the progression of initial periodontal pathology. Doppler flowmetry is a useful tool in the diagnosis, monitoring, prognosis and management of periodontal patients which allows access not only of gingival blood flow but also of pulpal microcirculation. Doppler flowmeters might help to realise the ultimate target of predictive, preventive and personalised periodontology tailored with respect to the particular patient. This article highlights the main working principles of laser Doppler flowmeters and the ultrasonic Doppler flowmeters. The advances in blood flow measurement by ultrasonic flowmetry are discussed.

Changes of pulp-chamber dimensions 1 year after rapid maxillary expansion

INTRODUCTION

The purpose of this study was to examine the effect of orthopedic forces on maxillary first molars' and maxillary central incisors' pulp chambers in children having rapid maxillary expansion as the only intervention compared with children having no orthodontic intervention by using cone-beam computed tomography images.

METHODS

In this prospective controlled clinical study, we evaluated 60 maxillary first molars and 60 maxillary central incisors from 30 children (18 boys, 12 girls) in the mixed dentition and during the pubertal growth period. The treated group had rapid maxillary expansion with the Haas expander, followed by 6 months of retention and 6 months of follow-up out of retention; the control group had no intervention during the study. Cone-beam computed tomography scans were taken initially and 1 year after the rapid maxillary expansion active phase. Initially, a 3-dimensional scrolling in all pulp chambers of the evaluated teeth was performed with Dolphin Imaging software (version 11.0; Dolphin Imaging & Management Solutions, Chatsworth, Calif) to describe the incidence of pulp-chamber calcifications. The dimensions of the pulp chambers of the molars and incisors were also investigated. Cross-sectional and longitudinal slices were used for each molar (coronal and axial slices) and incisor (sagittal and axial slices). The area (mm(2)) was obtained from 3 slices of each kind (6 measurements for each tooth).

RESULTS

The results suggest that rapid maxillary expansion did not induce new pulp-chamber calcification. Also, it did not interfere in normal pulp-chamber dimension changes of the anchorage molars.

CONCLUSIONS

The pulp chamber of the central incisors can be expected to be minimally wider 1 year after the therapy.

Metabolic changes of human dental pulp after rapid palatal expansion

OBJECTIVES

To investigate rapid palatal expansion (RPE)-induced metabolic changes in human dental pulp by measuring the expression and activity of aspartate aminotransferase (AST).

METHODS

mRNA and protein levels of AST in human dental pulp were measured by quantitative real-time polymerase chain reaction and Western blot, respectively. Furthermore, the activity of AST was measured by a full automatic biochemical analyzer.

RESULTS

AST mRNA and protein levels were found to be expressed in normal dental pulp. Moreover, the expression of AST was increased significantly after 14 days of RPE and then decreased at 1 month in retention. Three and 6 months after RPE, the AST expression level was gradually decreased to its baseline level. Similarly, AST activity was significantly elevated after 14 days of RPE, which was then down-regulated at 1 month in retention but was still kept at a higher level as compared with the control group. The enzymatic activity of AST was slowly decreased to its baseline level at 3 and 6 months in retention.

CONCLUSIONS

These results showed that significant reversible metabolic changes occurred in dental pulp during RPE, which revealed the high capacity of the pulp tissue for adaptation to this orthopedic method.

Does rapid maxillary expansion induce adverse effects in growing subjects?

OBJECTIVE

To assess the scientific evidence that rapid maxillary expansion (RME) causes Adverse Effects on the midpalatal suture, vertical dimension, dental and periodontal structures in growing subjects.

MATERIALS AND METHODS

Electronic databases were searched for articles dated through December 2011. The quality of the studies was ranked on a 13-point scale in which 1 was the low end of the scale and 13 was the high end.

RESULTS

Thirty relevant articles were identified. The amount of midpalatal suture opening ranged from 1.6 to 4.3 mm in the anterior region and from 1.2 to 4.4 mm in the posterior region. At the end of the active phase, RME resulted in slight inferior movement of the maxilla (SN-PNS +0.9 mm; SN-ANS +1.6 mm), increased tipping of anchored teeth from 3.4° to 9.2° and bending of the alveolar bone from 5.1° to 11.3°. In the long term, RME did not modify the facial growth patterns, and no significant changes on dentoalveolar structures were observed. Of the 30 studies, 2 were medium-high quality, 8 were medium quality, and 20 were low quality.

CONCLUSIONS

RME always opened the midpalatal suture in growing subjects. The vertical changes were small and transitory. In the long-term evaluation, an uprighting of anchored teeth was observed and periodontal structures were not compromised.