Ultrastructure of early mineral deposition during hyaline layer formation in rat molars

There is no consensus on whether the first mineralized layer, the hyaline layer, that is juxtaposed to root dentine is a variety of dentine or cementum or even a tissue of epithelial origin. Some suggest that there is no intermediate tissue between the acellular extrinsic fibre cementum (AEFC) and the root dentine. Here, to study hyaline layer formation and mineralization we examined by transmission electron microscopy the early stages of root development in upper molars from 10 to 13 day old Wistar rats. In addition to conventionally processed material, undemineralized and unstained sections were examined, which showed the deposition of fine mineral crystals in contact with the mineralized surface of root dentine. Early mineralization of the hyaline layer occurred in the region of the inner basement membrane, which persisted between the inner cellular layer of Hertwig's epithelial root sheath and the outer mineralized root dentine. When the root sheath began its fragment, collagen fibrils from the developing periodontal ligament began to insert into the mineralising hyaline layer, which was 0.5-0.8 micron wide. As the fragmentation of the root sheath HERS increased, more collagen fibrils appeared intermingled with the mineralising hyaline layer. In more advanced stages, when the hyaline layer had become fully mineralized and the formation of the AEFC began, the hyaline layer could no longer be identified. Thus, the hyaline layer is clearly discernible at early stages of periodontal development. Subsequently, it is masked by intermingling of cementum and dentine and therefore it is not possible to detect it in the formed roots of rat molars.     

Reliability of assessing interproximal bone loss by digital radiography: intrabony defects

AIM: The aim of the present study was to assess the reproducibility and validity of linear measurements of interproximal bone loss in intrabony defects on digitized radiographic images after application of different filters and magnifications. METHODS: Immediately before surgery 50 radiographs of 50 periodontally diseased teeth exhibiting interproximal intrabony defects were obtained by a standardized technique in 50 patients. Intrasurgically the distances from the cementoenamel-junction (CEJ) to the alveolar crest (AC) and from the CEJ to the deepest extension of the bony defect (BD) were assessed. All radiographs were digitized by a flatbed scanner (resolution: 600x1200 dpi). Using the FRIACOM-soft ware, the linear distances CEJ to AC and CEJ to BD were measured at 50 intrabony defects on digitized but unchanged radiographic images and also after use of 2 different basic image processing modes (filters: enhancement of grey level differences, spreading of grey values) with 7-fold and 14-fold magnification by 2 different examiners. RESULTS: Repeated measures MANOVA revealed reproducibility of the measurement of the distance CEJ to AC to be significantly influenced by examiner (p=0.027) and filter in combination with the height of 2 wall component of the intrabony defect (p=0.066). For the distance CEJ to BD filters had significant influence on reproducibility in correlation with vertical angulation difference (p=0.001). On the average in this study radiographic measurements tended to overestimate the amount of bone loss as assessed by intrasurgical measurements (CEJ-AC: 0.74-1.91 mm; CEJ-DB: -0.04-0.77 mm). Validity of measurement of the distance CEJ-AC was shown to be significantly influenced by the depth of the intrabony defect (p<0.003). Validity of the distance CEJ-BD was significantly influenced by intrasurgically assessed bone loss (p=0.029), horizontal angulation (p=0.066). Filters influenced the validity only in combination with examiner (p<0.001). CONCLUSIONS: In this study, the chosen digital manipulations (filters: spreading, structure) of radiographic images failed to result in statistically significantly more reproducible or valid measurements of interproximal bone loss within intrabony defects when compared to the digitized but unchanged images. All radiographic assessments on the digitized images except for use of enhancement of grey level differences (structure) came close to the intrasurgical gold standard.     

The influence of plaque and/or excessive loading on marginal soft and hard tissue reactions around Brånemark implants: a review of literature and experience

High implant survival rates are published with more than 15 years of observation time. Failures over time are often caused by ongoing marginal bone loss. Therefore, the need for reliable monitoring of the stability of periimplant attachment and/or bone level is extremely important. Marginal bone loss around osseointegrated implants has often been associated with periimplantitis, but clinical observations cannot prove this relationship. Otherwise, the impact of excessive loading on periimplant bone has been shown in animal studies and has been positively related to implant failure in terms of implant mobility and marginal bone loss. Some clinical observations support this hypothesis.     

Recommendations for optimal distraction protocols for various animal models on the basis of a systematic review of the literature

The principles of orthopaedic distraction osteogenesis (DO) have been successfully applied to the craniofacial skeleton, but the latency time, rate and rhythm of distraction, and length of the consolidation period that are optimal for long-bone distraction may be suboptimal for craniofacial DO. The aim of this study was to provide recommendations for optimal distraction parameters in animal experimental research on craniofacial DO. The data used were from studies, added to the PubMed database between 1 January 1973 and 1 January 2007, on the outcome of DO resulting from variations in a single distraction parameter while standardizing the other distraction parameters. Although experimental animal group sizes were rather small, especially in those studies that used large animals, and both skeletally mature and immature animals were used, the (in most cases quantitative) data provided useful information on the optimal parameters in craniofacial DO. A latency period may not be necessary at all. Distraction should be performed at a rate of 1mm/day (this may be halved when small animals such as rats are used) preferably with a continuous rhythm, followed by a consolidation period of 6-8 weeks. These recommendations can be used as basic guidelines for further animal experimental studies on craniofacial DO.     

The long-term effect of a mouthrinse containing essential oils on dental plaque and gingivitis: a systematic review

BACKGROUND: The purpose of this study was to review the literature on the effects of a mouthrinse containing essential oils (EO) on plaque and parameters of gingival inflammation. METHODS: The MEDLINE and Cochrane Central Register of Controlled Trials were searched up to and including December 2006 to identify appropriate studies. The primary outcome measure was gingivitis. Secondary parameters were plaque and, when reported, staining. RESULTS: Independent screening of titles and abstracts of 566 papers resulted in 11 publications that met the criteria of eligibility. In all studies, EO was used as an adjunct to regular daily toothbrushing. A statistically significant reduction in overall gingivitis was noted compared to the control (weighted mean difference [WMD]: -0.32, 95% confidence interval [CI]: -0.46 to -0.19, P <0.00001; test for heterogeneity: P <0.00001, I(2) = 96.7%). For interproximal sites the use of the test mouthrinse resulted in significantly more gingivitis reduction compared to control mouthrinse (WMD: -0.29, 95% CI: -0.48 to -0.11, P = 0.002; test for heterogeneity: P <0.00001, I(2) = 95.18%), whereas no differences were observed compared to dental floss. With respect to plaque scores, EO produced significant overall reductions in plaque (WMD: -0.83, 95% CI: -1.13 to -0.53, P <0.00001; test for heterogeneity: P <0.00001, I(2) = 96.1%). Separate analysis for interproximal areas revealed that EO resulted in more pronounced plaque drops compared to the control mouthrinse (WMD: -1.02, 95% CI: -1.44 to -0.60, P <0.00001; test for heterogeneity: P <0.00001, I(2) = 96.1%) or the use of floss (WMD: -0.75, 95% CI: -1.15 to -0.363, P <0.0002; test for heterogeneity: P <0.0002, I(2) = 93.0%). Most studies agreed that EO did not produce more staining than the control products. CONCLUSION: When used as an adjunct to unsupervised oral hygiene, EO provides an additional benefit with regard to plaque and gingivitis reduction as compared to a placebo or control.     

Occlusal measurement method can affect SEMG activity during occlusion

Summary Occlusal indicators are widely used in dental treatment to measure tooth contacts that occur during occlusion. However, the presence of an indicator may affect the mechanics of occlusion and lead to invalid tooth contact data. The objective of this study was to determine the effect of four indicators (Parkell, silk, T‐Scan^® sensor and paper) on surface electromyography (SEMG) activity during occlusion. Twenty‐three subjects performed strong bites and maximum clenches onto the four indicators and natural dentition. Surface electromyography recordings of anterior temporalis and superficial masseter activity and the subjects’ perception of each indicator were measured. SEMG activity with the T‐Scan^® sensor and paper was significantly different (higher masseter activity; P < 0·05) compared to that for natural dentition. The Parkell and silk gave no significant differences to natural dentition. Similarly, subjects perceived that T‐Scan^® sensor and paper had the greatest effect on occlusion and were the least comfortable (P < 0·05). Thus, the very plastic T‐Scan^® sensor and very thick articulating paper both affected SEMG activity during occlusion and, therefore, may not provide valid tooth contact information for dental treatment. In conclusion, occlusal indicators can change SEMG activity during occlusion which may affect the validity of the measurements they provide.     

Genome-wide association scan for childhood caries implicates novel genes

Dental caries is the most common chronic disease in children and a major public health concern due to its increasing incidence, serious health and social co-morbidities, and socio-demographic disparities in disease burden. We performed the first genome-wide association scan for dental caries to identify associated genetic loci and nominate candidate genes affecting tooth decay in 1305 US children ages 3-12 yrs. Affection status was defined as 1 or more primary teeth with evidence of decay based on intra-oral examination. No associations met strict criteria for genome-wide significance (p < 10E-7); however, several loci (ACTN2, MTR, and EDARADD, MPPED2, and LPO) with plausible biological roles in dental caries exhibited suggestive evidence for association. Analyses stratified by home fluoride level yielded additional suggestive loci, including TFIP11 in the low-fluoride group, and EPHA7 and ZMPSTE24 in the sufficient-fluoride group. Suggestive loci were tested but not significantly replicated in an independent sample (N = 1695, ages 2-7 yrs) after adjustment for multiple comparisons. This study reinforces the complexity of dental caries, suggesting that numerous loci, mostly having small effects, are involved in cariogenesis. Verification/replication of suggestive loci may highlight biological mechanisms and/or pathways leading to a fuller understanding of the genetic risks for dental caries.     

Subjective patients' opinion and evaluation of halitosis using halimeter and organoleptic scores

Objectives:  The aim of the study was to evaluate the level of interest in fetor ex ore among respondents, patients of the Department of Conservative Dentistry in Warsaw.
Materials and Methods:  A questionnaire was completed by 295 patients, 202 females and 93 males aged 18–74 years (average 38.73 years). Each person was also examined for organoleptic score and volatile sulfur compounds (VSC) by Halimeter. Halitosis was diagnosed if the average level of VSC was ≥125 ppb and the organoleptic measurement using a 0–5 point scale was ≥2. Statistical analysis was performed using chi-square test.
Results:  Incidence of halitosis was greatest in age ranges 25–34 years (29.68%) and 45–54 years (24.52%). Sixty-eight (43.87%) persons with diagnosed halitosis frequently reported having a problem with bad breath and only 5.81% persons with halitosis did not notice this problem ( P  < 0.001). Among 54 healthy persons three (5.56%) reported having a problem with halitosis ( P  < 0.001).
Conclusion:  A statistically significant correlation was found between clinical organoleptic diagnosis of halitosis and VSC level by halimeter. Subjective patients' opinion correlated well with objective evaluation of halitosis.