Use of a triple antibiotic solution affects the healing process of intentionally delayed replanted teeth in mice

ObjectiveA mixture of ciprofloxacin, metronidazole, and minocycline (3Mix) has been reported to be effective against oral bacteria from carious and endodontic lesions in vitro and in vivo. The objective of this study was to establish an animal model using mice for the application of 3Mix following intentionally delayed tooth replantation and to investigate the effects of 3Mix on the healing process of dental pulp and periodontal tissues.MethodsUpper first molars of ICR mice were extracted, immersed in 3Mix solution at different concentrations for 5–60 min with or without the use of a transfer solution (phosphate buffer solution (PBS)), in addition to transfer solution alone, and subsequently repositioned in the sockets. Immunohistochemistry for nestin and Ki-67, histochemistry for TRAP, and TUNEL assay were performed to assess pulpal healing during days 7–21.ResultsIncreased apoptosis was observed in the PBS group at week 1, followed by cell proliferation at week 2, and tertiary dentin and/or bone-like tissue formation at week 3. In contrast, nestin-positive, newly differentiated, odontoblast-like cells began to align along the pulp–dentin border following the appearance of Ki-67- and TUNEL-positive cells during weeks 1–2 in the 3Mix groups, suggesting that pulpal healing was accelerated. Severe root ankylosis was observed exclusively in the 3Mix groups. Rinsing with PBS before replantation partially rescued the viability of the periodontal ligament, but pulpal healing was delayed.ConclusionsThe application of 3Mix promotes pulpal regeneration of intentionally delayed replanted teeth; however, its use may induce severe damage to periodontal tissues.     

Reports

Abstract

In the past, vertical intrusive movement of teeth has been considered difficult and most routine clinical vertical movement of teeth has been confined to extrusion. It has been suggested that attempts at intrusion may result in an increased incidence of root resorption and also in occasional devitalization.

The displacement and resulting stress fields associated with such treatment can be successfully studied using the finite element method. In the case being considered initial movements are known to be small; therefore, the assumption in the study that the material behaves linear-elastically is considered to be reasonable.

This study of vertical tooth movement demonstrated that the maximum cervical margin stress in the periodontal ligament was 0·0046 N/mm², whilst the highest apical stress was 0·00205 N/mm² when intrusive and extrusive forces of 1 Newton were applied to the buccal surface of the crown of a tooth model. These stresses were evaluated in the light of previous studies and found to be within the suggested clinical optimum level. However, the periodontal stress distribution following orthodontic loading within this three-dimensional finite element model was found to be highly complex.     

Odontometric evaluation of mandibular premolars with tooth shape deviation: A case-control study

Objective:To evaluate the mean dimensions and morphologic characteristics of mandibular premolars that had mesiodistally elongated and faciolingually squeezed tooth shape deviations (MnP-TSD) and determine the population prevalence of this anomaly.Materials and Methods:Clinical photographs and study models were made for all new patients with MnP-TSD teeth who were seen over 20 years. The mesiodistal (MD) and faciolingual (FL) dimensions of the anomalous premolars were measured. MD/FL indices and MD × FL mm² occlusal crown areas were calculated and means and standard deviations were derived. Male and female means from the mandibular first and second anomalous premolars (MnP1/MnP2-TSD) were statistically compared against gender-specific means derived from published normative data using Student''s t-tests and chi-square tests.Results:Fifty-six individuals (33 male and 23 female) with MnP-TSD were identified, giving a male to female ratio of 1.4∶1, while the prevalence rate in the indigenous British population was estimated to be 0.6%. The MD widths of the MnP1-TSD and MnP2-TSD teeth were approximately 1 mm wider than normal, while the FL diameters were about 0.5 mm and 1.5 mm narrower respectively, for the first and second premolar teeth. The MD/FL indices, instead of being under 90 as usual were above 100, while the mean MD/FL mm² crown surface areas were normal.Conclusions:This study supplies odontometric dimensional and morphologic data on MnP-TSD teeth that provide a reference source for future comparisons.     

Accuracy of five electronic foramen locators with different operating systems: an ex vivo study

Objective:

The aim of this study was to evaluate, ex vivo, the precision of five electronic root canal length measurement devices (ERCLMDs) with different operating systems: the Root ZX, Mini Apex Locator, Propex II, iPex, and RomiApex A-15, and the possible influence of the positioning of the instrument tips short of the apical foramen.

Material and Methods:

Forty-two mandibular bicuspids had their real canal lengths (RL) previously determined. Electronic measurements were performed 1.0 mm short of the apical foramen (-1.0), followed by measurements at the apical foramen (0.0). The data resulting from the comparison of the ERCLMD measurements and the RL were evaluated by the Wilcoxon and Friedman tests at a significance level of 5%.

Results:

Considering the measurements performed at 0.0 and -1.0, the precision rates for the ERCLMDs were: 73.5% and 47.1% (Root ZX), 73.5% and 55.9% (Mini Apex Locator), 67.6% and 41.1% (Propex II), 61.7% and 44.1% (iPex), and 79.4% and 44.1% (RomiApex A-15), respectively, considering ±0.5 mm of tolerance. Regarding the mean discrepancies, no differences were observed at 0.0; however, in the measurements at -1.0, the iPex, a multi-frequency ERCLMD, had significantly more discrepant readings short of the apical foramen than the other devices, except for the Propex II, which had intermediate results. When the ERCLMDs measurements at -1.0 were compared with those at 0.0, the Propex II, iPex and RomiApex A-15 presented significantly higher discrepancies in their readings.

Conclusions:

Under the conditions of the present study, all the ERCLMDs provided acceptable measurements at the 0.0 position. However, at the -1.0 position, the ERCLMDs had a lower precision, with statistically significant differences for the Propex II, iPex, and RomiApex A-15.     

Effect of silver and fluoride ions on enamel demineralization: a quantitative study using micro-computed tomography

Background: This study aimed to investigate the effect of silver and fluoride ions on demineralization of enamel. Methods: The coronal parts of 40 extracted sound premolars were prepared into tooth blocks. An unvarnished occlusal surface window (OW) and a flat buccal/lingual surface window (FW) were created for each tooth by covering all other surfaces with an acid‐resistant varnish. These blocks were randomly allocated into four groups of 10 blocks each and immersed in respective solutions for 5 minutes: Group 1 – 2.36 M silver fluoride; Group 2 – 2.36 M potassium fluoride; Group 3 – 2.36 M silver nitrate; and Group 4 – deionized water. After 7‐day immersion in a buffered demineralization solution at pH 4.4, micro‐CT scans were taken. Results: Mean lesion depth in the FW area for tooth blocks in AgF, KF, AgNO₃ and control groups were 0 μm, 3.3 ± 10.3 μm, 156.3 ± 30.8 μm, and 173.6 ± 48.6 μm, respectively (p < 0.001). The difference in mean lesion depth between the AgNO₃ and control groups was not statistically significant (p > 0.05). Similar OW and FW lesions were observed in tooth blocks in the AgNO₃ and control groups. Conclusions: Topical application of a 2.36 M fluoride solution can inhibit demineralization of enamel while topical application of silver ions has little effect.     

Congenital absence of superficial posterior compartment calf muscles

Although various congenital abnormalities have been described, congenital absence of calf musculature is extremely rare, with only one report on its complete absence. We are the first to describe a case of congenital absence of muscles of the superficial posterior compartment of the calf presenting in a toddler. The child presented with a history of a painless limp, however no significant difference was found in functional gait analysis. We suggest that such cases should be monitored and parents can be reassured that no immediate treatment is required.     

Detection of the gubernacular canal and its attachment to the dental follicle may indicate an abnormal eruption status

Objectives:To evaluate and compare the detection of gubernacular canals (GC) and their characteristics in normal and abnormal tooth eruption.Materials and Methods:Patients with unerupted teeth were classified according to sex and age. Each tooth was classified according to dental group, eruption status, formation status, angulation, and GC detection. The opening of the GC in the alveolar crest and the attachment sites in relation to the dental follicle were assessed. Data were analyzed by the chi-square and Kruskal-Wallis tests, with a significance level of 5%.Results:Cone-beam computed tomography scans of 159 patients were evaluated. The final sample (N = 598) consisted of 423 teeth with normal eruption, 140 impacted teeth, and 35 teeth with delayed eruption. The overall detection rate of GC was 90.6%. These rates were 94.1%, 87.1%, and 62.9% for normal eruption, impacted teeth, and delayed eruption, respectively. GC detection rates were higher in the early stages of tooth formation in normal tooth eruption and in impacted teeth. The rate of GC detection was even lower in delayed teeth when they were angulated. Unusual attachment sites of the GC to the dental follicle were associated with abnormal eruption status.Conclusions:The results of the present study suggest that GC characteristics may indicate an abnormal eruption status.