Remineralization of enamel subsurface lesions by chewing gum with added calcium

Objectives

Chewing sugar-free gum has been shown to promote enamel remineralization. Manufacturers are now adding calcium to the gum in an approach to further promote enamel remineralization. The aim of this study was to compare the remineralization efficacy of four sugar-free chewing gums, two containing added calcium, utilizing a double-blind, randomized, crossover in situ model.

Methods

The sugar-free gums were: Trident Xtra Care, Orbit Professional, Orbit and Extra. Ten subjects wore removable palatal appliances with four human-enamel half-slab insets containing subsurface demineralized lesions. For four times a day for 14 consecutive days subjects chewed one of the chewing gums for 20 min. After each treatment the enamel slabs were removed, paired with their respective demineralized control slabs, embedded, sectioned and mineral level determined by microradiography. After 1-week rest the subjects chewed another of the four gums and this was repeated until each subject had used the four gum products.

Results

Chewing with Trident Xtra Care resulted in significantly higher remineralization (20.67 ± 1.05%) than chewing with Orbit Professional (12.43 ± 0.64%), Orbit (9.27 ± 0.59%) or Extra (9.32 ± 0.35%). The form of added calcium in Trident Xtra Care was CPP–ACP and that in Orbit Professional calcium carbonate with added citric acid/citrate for increased calcium solubility.

Conclusions

Although saliva analysis confirmed release of the citrate and calcium from the Orbit Professional gum the released calcium did not result in increased enamel remineralization over the normal sugar-free gums. These results highlight the importance of calcium ion bioavailability in the remineralization of enamel subsurface lesions in situ.     

SUGAR-FREE CHEWING GUM AND DENTAL CARIES – A SYSTEMATIC REVIEW

Objective:

To appraise existing evidence for a therapeutic / anti-cariogenic effect of sugar-free chewing gum for patients.

Method:

9 English and 2 Portuguese databases were searched using English and Portuguese keywords. Relevant articles in English, German, Portuguese and Spanish were included for review. Trials were excluded on lack of randomisation, control group, blinding and baseline data, drop out rate >33%, no statistical adjustment of baseline differences and no assessment of clinically important outcomes. Reviews were excluded on lack of information, article selection criteria, search strategy followed, search keywords, searched databases or lack of study-by-study critique tables. In cases of multiple reports from the same study, the report covering the longest period was included. Two reviewers independently reviewed and assessed the quality of accepted articles.

Results:

Thirty-nine articles were included for review. Thirty were excluded and 9 accepted. Of the 9 accepted, 2 trials of reasonable and good evidence value did not demonstrate any anti-cariogenic effect of sugar-free chewing gum. However, 7 articles, with 1 of strong, and 6 of good evidence value, demonstrated anti-cariogenic effects of chewing Sorbitol, Xylitol or Sorbitol/Xylitol gum. This effect can be ascribed to saliva stimulation through the chewing process, particularly when gum is used immediately after meals; the lack of sucrose and the inability of bacteria to metabolize polyols into acids.

Conclusion:

The evidence suggests that sugar-free chewing gum has a caries-reducing effect. Further well-designed randomised trials are needed to confirm these findings.     

An Ex Vivo Comparison of Electronic Apex Locator Teaching Models

Introduction

This study aimed to develop a simple and inexpensive ex vivo model to teach students the use of electronic apex locators in a preclinical setting.

Methods

Using 27 extracted human teeth, the Raypex 5 (VDW, Munich, Germany) and Dentaport ZX (J. Morita Co, Kyoto, Japan) were tested in three different media (ie, alginate, sugar-free gelatin, and 0.9% sodium chloride solution). Working lengths determined by these models were compared with those obtained by digital radiography and direct visualization using a linear mixed modeling statistical approach.

Results

Raypex 5 exhibited a higher percentage of measurements accurate to ±0.5 mm and ±1.0 mm of the control across all three media in all tooth types. In multirooted teeth, alginate showed the highest accuracy.

Conclusions

The most accurate EAL/embedding medium combination was Raypex 5/alginate to both ±0.5 mm and ±1.0 mm of the control. The model tested in this study was accurate, easy to assemble, and cost-effective, making it suitable for teaching purposes.     

Cardiovascular and muscle activity during chewing in whiplash-associated disorders (WAD)

Objective

The present study aimed to elucidate possible physiological mechanisms behind impaired endurance during chewing as previously reported in WAD. We tested the hypothesis of a stronger autonomic reaction in WAD than in healthy subjects in response to dynamic loading of the jaw-neck motor system.

Design

Cardiovascular reactivity, muscle fatigue indicies of EMG, and perceptions of fatigue, exhaustion and pain were assessed during standardised chewing. Twenty-one WAD subjects and a gender/age matched control group participated. Baseline recordings were followed by two sessions of alternating unilateral chewing of a bolus of gum with each session followed by a rest period.

Results

More than half of the WAD subjects terminated the test prematurely due to exhaustion and pain. In line with our hypothesis the chewing evoked an increased autonomic response in WAD exhibited as a higher increase in heart rate as compared to controls. Furthermore, we saw consistently higher values of arterial blood pressure for WAD than for controls across all stages of the experiment. Masseter EMG did not indicate muscle fatigue nor were there group differences in amplitude and mean power frequency. Pain in the WAD group increased during the first session and remained increased, whereas no pain was reported for the controls.

Conclusion

More intense response to chewing in WAD might indicate pronounced vulnerability to dynamic loading of the jaw-neck motor system with increased autonomic reactivity to the test. Premature termination and autonomic involvement without EMG signs of muscle fatigue may indicate central mechanisms behind insufficient endurance during chewing.     

Synchrotron radiation microbeam X-ray fluorescence analysis of zinc concentration in remineralized enamel in situ

Objective

Remineralization is an indispensable phenomenon during the natural healing process of enamel decay. The incorporation of zinc (Zn) into enamel crystal could accelerate this remineralization. The present study was designed to investigate the concentration and distribution of Zn in remineralized enamel after gum chewing.

Methods

The experiment was performed at the Photon Factory. Synchrotron radiation was monochromatized and X-rays were focused into a small beam spot. The X-ray fluorescence (XRF) from the sample was detected with a silicon (Si) (lithium (Li)) detector. X-ray beam energy was tuned to detect Zn. The examined samples were small enamel fragments remineralized after chewing calcium phosphate-containing gum in situ. The incorporation of Zn atom into hydroxyapatite (OHAP), the main component of enamel, was measured using Zn K-edge extended X-ray absorption fine structure (EXAFS) with fluorescence mode at the SPring-8.

Results

A high concentration of Zn was detected in a superficial area 10-μm deep of the sectioned enamel after gum chewing. This concentration increased over that in the intact enamel. The atomic distance between Zn and O in the enamel was calculated using the EXAFS data. The analyzed atomic distances between Zn and O in two sections were 0.237 and 0.240 nm.

Conclusion

The present experiments suggest that Zn is effectively incorporated into remineralized enamel through the physiological processes of mineral deposition in the oral cavity through gum-chewing and that Zn substitution probably occurred at the calcium position in enamel hydroxyapatite.     

Reverse sandwich restoration for the management of invasive cervical resorption: a case report

Introduction

Invasive cervical resorption (ICR) may occur as a consequence of trauma, orthodontic treatment, intracoronal bleaching, and surgical procedures and may lead to the progressive and destructive loss of tooth structure. The restoration of these resorptive defects is a challenging task because no single restorative material possesses good sealing ability, reinforcement of remaining tooth structure, and biocompatibility simultaneously.

Methods

This case presented with invasive cervical resorption class 2 (Heithersay) and apical inflammatory resorption caused by trauma in tooth #9. The surgical management of ICR was performed, and, finally, the roots were externally reinforced by filling the resorptive defect with a combination of composite and resin-modified glass ionomer cement, proposed as reverse sandwich restoration (RSR).

Results

This novel RSR was well tolerated by the periodontal tissues. A follow-up x-ray showed no pathological changes and no recurrence of resorption.

Conclusions

This case report presents a treatment strategy for root reinforcement that might improve the healing outcomes for patients with invasive cervical resorption.     

Influence of fluoride concentration and ethanol pre-treatment on the reduction of the acid susceptibility of enamel

Objective

To determine the association between KOH-soluble and structurally bound fluoride uptake and the erosion resistance of enamel, respectively. Additionally, the effect of enamel pre-treatment with ethanol before fluoridation was assessed.

Methods

Sixty bovine incisors (4 specimens/tooth) were randomly allocated to six groups (A-F). Samples 1 and 2 remained untreated, serving as control at baseline. Pre-treatment of the samples was performed for 5 min with 99% ethanol (groups A, B and C) or physiologic saline (groups D, E and F). Samples 3 and 4 were treated either with 0.5% (groups A and D), 1.0% (groups B and E) or 1.5% (groups C and F) fluoride solution. In samples 1 and 3, uptake of KOH-soluble and structurally bound fluoride was determined. Samples 2 and 4 were used for the determination of acid susceptibility by immersion in 1 ml HCl for 30 s. Calcium release into HCl was assessed by atomic absorption spectroscopy. Differences between the groups were calculated by unpaired t-tests (p < 0.05).

Results

Mode of pre-treatment showed no influence on fluoride acquisition. KOH-soluble and structurally fluoride uptake increased with increasing fluoride concentrations. Highest acid resistance was observed after treatment with 1% fluoride solution for both kinds of pre-treatment followed by 1.5% and 0.5% fluoride solution.

Conclusion

Dose-dependency was observed for enamel fluoride acquisition but not for acid resistance.     

The effect of low intensity pulsed ultrasound in a 3D ex vivo orthodontic model

Objectives

This study investigated the effects of low intensity pulsed ultrasound (LIPUS) on dentoalveolar structures during orthodontic force application using a novel organ culture system.

Methods

Mandibles were dissected from 28-day-old male Sprague Dawley rats, sliced into 1.5 mm and cultured at 37 °C and 5% CO₂, prior to application of a 50 g force to each mandible slice. Slices were randomly divided into three groups of control, 5 and 10 min LIPUS application and cultured for five days before histological and histomorphometrical analysis.

Results

Cementum and predentine thickness and subodontoblast and periodontal ligament cell counts were increased in the ultrasound groups, with increases statistically significant in the 10 min treated groups. Odontoblasts remained viable during LIPUS exposure and osteoclast activity was increased by LIPUS.

Conclusions

LIPUS may influence remodelling of the dentine-pulp complex and associated tissues during orthodontic force application ex vivo.     

Two-dimensional patterns of human enamel thickness on deciduous (dm1, dm2) and permanent first (M1) mandibular molars

Objective

To characterise patterns of enamel thickness on deciduous (dm1, dm2) and permanent first (M1) mandibular molars and evaluate these against functional and morphological interpretative models.

Methods

Histological sections of mesial and distal cusps from 69 unworn molars were produced and examined using transmitted light microscopy. Enamel cap area, dentine area, as well as average and linear measurements of enamel thickness were recorded from digital images of the sections using image analysis software. Comparisons were made along the molar row, and between the mesial and distal sections of each tooth, using univariate and multivariate inferential statistics.

Results

The enamel cap area, dentine area, and average enamel thickness increased from the anterior to the posterior molars. The greatest proportional increase in linear enamel thickness occurred between the outside surface of the lingual cusps when dm1 was compared to dm2, and between the outside surface of the buccal cusps when dm2 was compared to M1. The enamel cap area increased from the mesial to the distal sections in M1. Dentine area decreased from the mesial to distal sections in dm1. Enamel cap and dentine areas did not change across dm2.

Conclusion

Results for the deciduous molars are interpreted within a functional model of mastication, in which the dm2 dissipates less laterally orientated loads compared to dm1. Differences in enamel thickness between dm2 and M1 support previous functional interpretations for this permanent molar. Some mesial-distal results are not easily explained from either a functional or a morphological perspective and suggest an underlying developmental constraint.     

Relationship between chewing side preference and handedness and lateral asymmetry of peripheral factors

Objective

To determine whether chewing side preference is related to handedness and lateral asymmetry of occlusal characteristics, muscular force and temporomandibular disorders (TMD) in a dentate population.

Design

One hundred and seventeen dentate adults participated in this cross-sectional study. Static and dynamic occlusal characteristics were determined at the maximal intercuspal position and at the lateral excursions by scanning interocclusal records and analysing them using image software. Unilateral maximum bite force and finger-thumb grip force were measured by means of a gnathodynamometer. TMD were assessed according to the Research Diagnostic Criteria for TMD. Chewing side preference and masticatory laterality were determined by observing the jaw's movement while each subject chewed silicone. Asymmetry or side difference of the variables was calculated. Correlation between side difference variables and masticatory laterality was studied using Spearman correlation coefficient.

Results

Fifty-nine subjects chewed on the right, 15 on the left and 43 chewed on both sides. There was no relationship between preferred chewing side and handedness, lateral asymmetry of TMD or side difference in finger-thumb grip force. Significant and positive correlations were observed between masticatory laterality and side differences in bite force and side differences in occlusal contact area at intercuspal position (P < 0.01).

Conclusions

Chewing side preference in a dentate population is related to lateral asymmetry of bite force and asymmetry of occlusal contact area at the intercuspal position but not to handedness.     

Whole saliva flow rate and body profile in healthy young adults

Objective

The purpose of this study was to clarify the effect of the body profile on the whole saliva flow rate in healthy male and female subjects.

Study design

The whole saliva flow rate was evaluated under unstimulated (UWSFR) and stimulated conditions by the gum test (SWSFR-GT) and Saxon test (SWSFR-ST), and its correlation with body profiles such as body height (BH), body weight (BW), body surface area (BSA) and body mass index (BMI) was analysed in 100 male and 100 female subjects.

Results

The averages of UWSFR, SWSFR-GT and SWSFR-ST and those of BH, BW, BSA and BMI were significantly larger in males than in females (p < 0.0001). No correlation was observed between any of UWSFR, SWSFR-GT and SWSFR-ST and any of BH, BW, BSA and BMI for either males or females. However, UWSFR, SWSFR-GT and SWSFR-ST were significantly correlated with BH, BW and BSA when data from male and female subjects were combined.

Conclusion

The whole saliva flow rate from an individual should only be compared with the data from the group of the same gender.     

Management of inflammatory external root resorption by using calcium-enriched mixture cement: a case report

Introduction

Inflammatory external root resorption is one of the major complications after replantation of avulsed teeth. Here we report a case of inflammatory external root resorption in a maxillary left central incisor in an 11-year old male patient that was managed and treated by using calcium enriched mixture (CEM) cement.

Methods

The patient’s chief complaint was mobility of avulsed and replanted maxillary left central incisor and pain in chewing on left central and lateral incisors. Radiographic examination showed progressive inflammatory external root resorption of the left central incisor with an inadequately obturated root canal treatment. Both teeth were immature and had periapical radiolucencies. Both teeth were irrigated copiously with 2.5% NaOCl and obturated with CEM cement. However, the central incisor was treated with calcium hydroxide 6 weeks before CEM cement obturation.

Results

The clinical and radiographic examinations at 3-, 6-, 12-, 24-, and 40-month follow-up showed that treated teeth were functional with normal mobility, the progression of the inflammatory external root resorption ceased, the resorptive lacunae were filled with newly formed bone, and periapical radiolucencies healed.

Conclusions

Considering the biological properties of CEM cement, especially its alkalinity and sustained calcium hydroxide release, using this novel cement for treatment of inflammatory external root resorption and obturation of immature necrotic teeth might be an applicable choice.     

Continued development of the root separated from the main root

Introduction

Endodontic infection or physical trauma of a developing tooth might lead to unusual situation for root development.

Methods

Two cases are presented. Both cases involved immature mandibular second premolars with infected pulps. In the first case, the tooth was treated by apexification, whereas revascularization procedures were performed in the second case. Interestingly, a separated root tip was observed with the main root at the initial presentation of case 2.

Results

At recall after apexification, a separate root tip was observed apically to the main root end, and root development continued in case 1. In the second case, the separate root displayed continuing root formation, but the main root did not gain root thickness or length.

Conclusions

These cases revealed that Hertwig’s epithelial root sheath and stem cells from the apical papilla can be separated from the main tooth structure by an external force or iatrogenic factors and thereafter produce a separate root tip.     

Application of cerium chloride to improve the acid resistance of dentine

Objective

To investigate the effect of cerium chloride, cerium chloride/fluoride and fluoride application on calcium release during erosion of treated dentine.

Methods

Forty dentine samples were prepared from human premolars and randomly assigned to four groups (1-4). Samples were treated twice a day for 5 days, 30 s each, with the following solutions: group 1 placebo, group 2 fluoride (Elmex fluid), group 3 cerium chloride and group 4 combined fluoride and cerium chloride. For the determination of acid resistance, the samples were consecutively eroded six times for 5 min with lactic acid (pH 3.0) and the calcium release in the acid was determined. Furthermore, six additional samples per group were prepared and used for EDS analysis. SEM pictures of these samples of each group were also captured.

Results

Samples of group 1 presented the highest calcium release when compared with the samples of groups 2-4. The highest acid resistance was observed for group 2. Calcium release in group 3 was similar to that of group 4 for the first two erosive attacks, after which calcium release in group 4 was lower than that of group 3. Generally, the SEM pictures showed a surface coating for groups 2-4. No deposits were observed in group 1.

Conclusion

Although fluoride showed the best protective effect, cerium chloride was also able to reduce the acid susceptibility of dentine significantly, which merits further investigation.     

Embolia cutis medicamentosa (Nicolau syndrome) after endodontic treatment: a case report

Introduction

Embolia cutis medicamentosa (Nicolau syndrome) is a rare iatrogenic event of tissue necrosis after intramuscular or intraarticular application of cristalloid suspensions. Clinically, it presents as a livid discoloration of the skin, local pain, and signs of inflammation.

Methods

This article presents the first case of Nicolau syndrome after the endodontic application of calcium hydroxide paste into the distal root canal of tooth 18. The patient presented to the Department for Maxillofacial Surgery and hospitalized for several days.

Results

The application of calcium hydroxide paste led to a thrombosis of the inferior alveolar artery and various branches of the maxillary artery. A definite necrosis of the left-side infraorbital skin area and concomitant hypaesthesia of the infraorbital nerve and of the mental nerve were observed.

Conclusions

Calcium hydroxide paste is appropriate for the medicamentous treatment of root canals, but is not suitable to stanch bleeding from periapical arteries.     

Trial of protective effect of fissure sealants, in vivo, on the palatal surfaces of anterior teeth, in patients suffering from erosion

Objectives

Previous work has shown protection to eroded teeth offered by a resin-based adhesive lasted up to three months. The hypothesis investigated in this study was whether application of a fissure sealant would offer longer protection.

Methods

Seventeen adult patients with palatal tooth wear were recruited and written consent obtained. Metal discs were cemented on the palatal surfaces of all upper anterior teeth following previously published techniques. Alternate teeth within each subject were randomly chosen and coated with a clear fissure sealant using previously published methods. The uncoated teeth were used as controls. Accurate impressions were taken in custom made trays and repeated at 3, 6, 9, 12 and 20 months and scanned using a non-contacting laser profilometer.

Results

The mean (standard deviation) thickness of the fissure sealant was 290 μm (500) at the start and after 3 months a mean thickness of 120 μm (260) remained. At this point the control surfaces showed a mean 70 μm (113) of tooth wear. At 6 and 9 months the mean wear for control teeth was higher at 120 μm (114) and 110 μm (114) than sealed teeth at 50 μm (260) and 60 μm (440), respectively. A comparison of paired sites within subjects at their final visit indicated a statistically significant difference in wear between the sealed and control teeth (p = 0.016).

Conclusions

The use of fissure sealant to protect palatal dentine surfaces may have a role in prevention of tooth wear for up to a period of nine months.     

Anesthetic efficacy of four percent articaine for pulpal anesthesia by using inferior alveolar nerve block and buccal infiltration techniques in patients with irreversible pulpitis: a prospective randomized double-blind clinical trial

Introduction

The study was designed as a randomized double-blind trial to evaluate the anesthetic efficacy of 4% articaine with 1:100,000 epinephrine in inferior alveolar nerve block (IANB) and infiltration anesthetic techniques to anesthetize mandibular molars with irreversible pulpitis.

Methods

The study was composed of 2 test arms and 1 control arm. Subjects in the test arms received either a standard IANB or a buccal infiltration (B Infil) of 4% articaine with 1:100,000 epinephrine, whereas the subjects in the control arm received a standard IANB of 2% lidocaine with 1:100,000 epinephrine. Subject’s self-reported pain response was recorded on Heft Parker Visual Analogue Scale after local anesthetic administration during access preparation and pulp extirpation.

Results

For statistical analysis Pearson χ², Student's paired t test, 1-way analysis of variance, and Friedman tests showed no significant difference in success rates among the 3 arms of the trial.

Conclusions

Although B Infil and IANB of 4% articaine were equally effective, B Infil can be considered a viable alterative in IANB for pulpal anesthesia in mandibular molars with irreversible pulpitis.     

Histomorphometric analysis and immunolocalization of RANKL and OPG during the alveolar healing process in female ovariectomized rats treated with oestrogen or raloxifene

Objective

To investigate the effects of bone-resorption inhibitors (oestrogen and raloxifene) on the RANKL/OPG balance during the chronology of the alveolar healing process in ovariectomized (OVX) rats by means of immunocolocalization and histomorphometric analysis.

Materials and methods

One hundred sixty female Wistar rats at 70 days of age were either OVX or sham-operated and divided into four groups: sham, OVX/Oil, OVX with E₂ replacement (17β-estradiol, 400 μg/month), OVX with RLX treatment (1 mg/kg bw/day). The 60-day treatment started 8 days after ovariectomy. The incisors were extracted to allow analysis of 7, 14, 21, 28 and 42 days of wound healing. After obtaining the histological samples, slides were stained with hematoxylin and eosin or subjected to immunocolocalization reaction for RANKL and OPG. Results were quantitatively evaluated.

Results

Histomorphometric analysis showed that the sham group presented the highest and OVX/Oil group the lowest mean bone formation value in the post-extraction period. The immunocolocalization analysis showed a larger increase in bone turnover at 7 postoperative days in OVX/Oil and sham groups and decreasing bone turnover in the other periods. The OVX/Oil group showed a large decrease in bone turnover at 14 postoperative days, a period demonstrated by mild cellular activity. OVX/E₂ and sham groups showed a decreased bone turnover at 28 postoperative days while OVX/RLX group showed a decreased bone turnover at 21 postoperative days. On the 42nd postoperative day, sham and OVX/RLX groups showed an established alveolar bone healing process.

Conclusions

Ovariectomy delays the alveolar healing process and interferes with bone turnover through the balance between RANKL and OPG. Oestrogen replacement or raloxifene treatment did not totally recover the oestrogen-deficient state. However raloxifene treatment showed more satisfactory results than oestrogen replacement.     

Three-year clinical outcome of single implant-retained mandibular overdentures--results of preliminary prospective study

Objectives

The aim of this preliminary prospective study was to evaluate the clinical outcome, the oral health-related quality of life (OHRQoL), and the subjective chewing ability of patients with mandibular complete dentures retained by a single implant placed in the mandible midline.

Methods

Patients wearing complete dentures were treated with a single implant in the mandible, followed by relining of the dentures and incorporation of ball attachments for implant retention. Implant outcome, prosthodontic maintenance, subjective chewing ability, and the oral health impact profile of the patients were assessed at baseline and at four weeks after connecting the denture and implant.

Results

Eleven patients were enrolled in this investigation, and the mean observation period was 43.4 months (minimum period: 35, maximum period: 52 months). No implants were lost during observation period, but four dentures needed repair because of the fracture of the denture base in the midline area. A significant improvement was observed in the OHRQoL of the patients after the attachment of the mandibular dentures with a single midline implant. Furthermore, the subjective chewing ability of the patients was significantly improved after implant connection.

Conclusions

Within the limitations of this preliminary prospective clinical study, single implant-supported mandibular overdentures were a successful treatment option for older edentulous patients who showed improvements in their OHRQoL and chewing ability.