Dental fracture fragment attachment: fracture model and luting agent comparisons

PURPOSE: The purpose of this study was twofold: 1. To compare two different research models for simulating a traumatic anterior tooth fracture: the blunt trauma method (standard method) and an AL2O3 sectioning method (experimental method). 2. To compare the bond strength of tooth fragments bonded with resin modified glass ionomer vs. a light cured composite resin. METHODS: Two hundred bovine incisors were used in the study and kept in plain tap water throughout. The study consisted of five basic steps: 1. Fracture of the teeth by either blunt trauma (chisel and hammer) or AL2O3 sectioning disc. 2. Luting of the fractured fragments back to the teeth using either a composite resin or resin modified glass ionomer. 3. Thermocycling of the repaired teeth. 4. Dislodging the teeth to determine the strength of repair. 5. Determination of fracture type. RESULTS: One-way ANOVA revealed a statistically significant difference in the forces required to fracture the resin modified glass ionomer and composite resin regardless of whether the teeth were originally fractured with the blunt force method (p=0.030) or the disc sectioning method (p=.001). One-way ANOVA also revealed a statistically significant difference between the forces required for fracture by blunt trauma and the disc fracture techniques with the resin modified glass ionomer group (p=0.000345). However, there was no significant difference when the two techniques were compared for the composite resin (p= 0.2941). CONCLUSIONS: 1. The resin modified glass ionomer was significantly stronger than the composite resin when both the blunt trauma and the disc fracture techniques were employed. 2. The study's results do not support substituting the ease of the AL2O3 disc for the more time-consuming blunt trauma method.     

Shoulder complaints after nerve sparing neck dissections

The purpose of the study was to analyse the prevalence of shoulder complaints after nerve sparing neck dissection at least 1 year after surgery, and to analyse the influence of radiation therapy on shoulder complaints. Patients were interviewed for shoulder complaints, and patients filled out the shoulder disability questionnaire to evaluate shoulder disability in daily activities. In total 137 patients; 51 after modified radical neck dissection (MRND), 21 after postero-lateral neck dissection (PLND), and 65 after supraomohyoid neck dissection (SOHND) were analysed. After MRND 33.3% of the patients experienced shoulder complaints, after PLND 66.7%, and after SOHND 20% of the patients experienced shoulder complaints. Type of neck dissection was significantly (P < 0.001) related to shoulder complaints. Outcome on the shoulder disability questionnaire also showed a significant (P < 0.01) difference in outcome for type of neck dissection. The prevalence of shoulder complaints after SOHND are low, and reduce disability in daily activities. Radiation therapy does not have a significant effect on shoulder complaints and disability.     

The effect of timing of surgery for velopharyngeal dysfunction on speech

The timing of surgery for velopharyngeal dysfunction has been based on assumptions about the relation between age, speech development, and velopharyngeal dysfunction. Cleft palate teams often counsel parents to have an intervention for velopharyngeal dysfunction performed earlier rather than later, believing that earlier interventions result in more rapid or better normalization of speech. The objective of this retrospective chart review study is to determine whether the age at surgical intervention for velopharyngeal dysfunction has an effect on the subsequent length of speech therapy. Of 174 patients included in the study database, 36 had velopharyngeal dysfunction for which further velopharyngeal management was required. Of the 36 patients who received surgical velopharyngeal dysfunction management, 27 had verifiable speech therapy records. These 27 patients represent the study population. The outcome measure was the total length of subsequent speech therapy until speech normalization. The data suggest that there is no relation between the age at velopharyngeal dysfunction surgical management and the amount of speech therapy needed to achieve normalization of the speech impairments secondary to velopharyngeal dysfunction after that management. In conclusion, 1) the age at surgical velopharyngeal dysfunction management (pharyngeal flap or sphincter pharyngoplasty) does not have an effect on subsequent normalization of speech as measured by the duration of speech therapy necessary to achieve normalization of the speech impairments secondary to velopharyngeal dysfunction after that management, and 2) the age at surgical velopharyngeal dysfunction management does not affect the likelihood of subsequent surgical velopharyngeal dysfunction management procedures.     

Molecular analysis of age-related changes of Streptococcus anginosus group and Streptococcus mitis in saliva

The purpose of this study was to survey the prevalence of streptococcal species, especially Streptococcus anginosus (which has been reported to be associated with cancer in the upper digestive tract), Streptococcus constellatus, and Streptococcus intermedius in the saliva of different age groups. A sequence analysis of 16S rDNA was performed and DNA quantified using real-time polymerase chain reaction. The S. anginosus level increased with age, whereas the levels of S. constellatus and S. intermedius did not change. Streptococcus mitis was the predominant species in the saliva of all the age groups but, unlike the S. anginosus, the proportion of S. mitis in the salivary bacteria decreased with age. The increase in S. anginosus with age should be carefully monitored because of its association with diseases, including cancer.     

Real-time quantitative polymerase chain reaction for enumeration of Streptococcus mutans from oral samples

This study compared SYBR Green real-time quantitative PCR (qPCR) with standard plate counting for the enumeration of Streptococcus mutans in oral samples. Oral samples (n = 710) were collected from high-caries-risk children for quantification of S. mutans by qPCR using primer pairs. The S. mutans copy number was calculated with reference to a qPCR quantification cycle (Cq) standard curve and compared with the absorbance value at 600 nm of a standard suspension of S. mutans UA159. The S. mutans copy number results were evaluated in relation to standard plate count (SPC) results obtained from each sample following culture on Petri plates containing S. mutans selective media and reported as colony-forming units (CFUs). The mean S. mutans copy number calculated from qPCR was higher than the SPC CFUs (1.3 × 10(6) and 1.5 × 10(5) CFUs, respectively). The qPCR values were usually higher in individual samples and qPCR detected the presence of S. mutans 84% (231/276) of the time that the SPC did not, compared with 33% (4/12) of the time when qPCR failed to detect S. mutans and the SPC did. The qPCR technique was found to be more sensitive for detection of S. mutans from oral samples, a method that is not dependent on the viability of the sample taken and therefore is proposed as a more reliable and efficient means of quantification of S. mutans.     

Provisional implants for immediate overdenture fixation after multiple tooth extraction

The aim of the study was to assess the effectiveness of immediate overdenture supported by provisional mini-implants after multiple tooth extraction. The study included 39 patients aged 55±17, followed up for 12 months. The first group included 14 patients with 65 mini-implants and 17 soft-lined immediate overdentures. In the second group (10 patients, 45 mini-implants) 12 immediate overdentures had hard liner. In the third group (15 patients) immediate overdentures with hard liner were used without implant support. 12-month implant survival was 98.5% in the I and 91.1% in the II group (1 and 4 implants failed correspondently). The number of denture basis corrections was minimal in the second group (2.9±0.46) and largest in the third group (4.32±0.67). Mini-implants provided better fixation of complete denture, facilitated mucosal adaptation to denture compared with immediate dentures without implant support.     

A prospective study of the prevalence of periapical pathology in severely worn teeth

The aim of this article was to carry out a prospective audit on a convenience sample of all new patients referred to the toothwear clinic at Cardiff University Dental Hospital to establish the prevalence of undiagnosed periapical pathology. CLINICAL RELEVANCE: The low prevalence value for undiagnosed periapical pathology in patients with advanced toothwear suggests that, for many patients, toothwear is a slow process which allows the defence mechanisms of the pulp to counteract the effects of wear. It also questions the necessity of taking routine radiographs of teeth with wear into dentine, in the absence of clinical symptoms. This would reduce the total radiation dose delivered to the patient and preserve valuable healthcare resources.     

Efficacy of enzymatic mouth rinses for immobilisation of protective enzymes in the in situ pellicle

Aim

Mouth rinses containing enzymes are designed for patients suffering from xerostomia. The objective of the present in situ study was to investigate the efficacy of these rinses for targeted accumulation and immobilisation of protective enzymes in the acquired pellicle.

Methods

A number of six healthy subjects carried bovine enamel slabs fixed on individual upper jaw splints for pellicle formation in situ. After 1 min, they rinsed with biotène or BioXtra for 10 min, respectively. Enzyme activities of lysozyme, peroxidase and glucoseoxidase in the in situ pellicle and in the saliva were assayed before as well as 0, 20 and 40 min after the rinses. The assays for the respective enzyme activities were based on fluorogenic substrates. Separate experiments were performed for the different enzymes and mouth rinses, respectively. Statistical evaluation was carried out with the Kruskal-Wallis test.

Results

None of the investigated rinses had any significant impact on the activities of lysozyme, peroxidase and glucoseoxidase detectable in the in situ pellicle or in the saliva (Kruskal-Wallis test, p > 0.05). Despite the fact that both products should contain lactoperoxidase activity according to manufacturers’ instructions, no peroxidase activity was measurable in the pure mouth rinses.

Conclusion

With the tested enzymatic mouth rinses targeted accumulation and immobilisation of protective enzymes in the in situ pellicle did not seem possible.