Odontiatrogenic tooth fracture

While the awareness of vertical tooth fractures, whether incomplete or complete, is increasing, sufficient attention has not been paid to the manner in which the dentist may contribute to the occurrence of these fractures. This paper focuses on the most likely areas in which the practitioner can either misdiagnose the presence of a fractured tooth or where dental procedures contribute to fracture of the tooth structure. For this type of fracture the authors propose the term 'odontiatrogenic tooth fracture'.     

Multidisciplinary aspects of root resection failure: a case report

Creative approaches to tooth maintenance often include tooth resection and retention of one or more of the roots. Although this procedure is reasonably successful, failure of supportive endodontic, periodontic, and restorative management of the retained roots can jeopardize a successful outcome. The following is a case report evaluating multiple aetiologies contributing to root resection failure.     

Effects of gender on serum biomarkers of systemic inflammation coincident to experimentally-induced periapical lesions

Objective

The literature suggests that females have less adverse effects to infection than males, due to the protective effects of oestrogen. The purpose of our study is to compare the systemic effects of induced periapical lesions between groups of animals with various serum concentrations of oestrogen.

Methods

To induce periapical inflammation, two molar tooth pulps were exposed in ovariectomized (OVX) and normal female (F) and castrated (Cast-M) and normal male (M) Sprague–Dawley rats (Experimental group, E). Sham-operated control animals from each group were also studied (Control group, C). Twenty-eight days later, serum and maxillas were collected. Serum 17β-oestradiol, testosterone, MMP-9, IL-18, IL-6, TNF-α, and IL-1β concentrations were measured by ELISA. Maxillas were cleaned of residual tissue and digital radiographs were made to verify the presence of periapical lesions. Data were compared by factorial ANOVA, post hoc Tukey, and Pearson correlation tests. Groups were considered to be significantly different when p < 0.05.

Results

The serum concentration of IL-18, TNF-α, IL-1-β, IL-6 and MMP-9 was greatest in OVX-E animals, compared to all other groups (p < 0.001). F-E rats had significantly higher serum concentrations of these cytokines, compared to F-C. The fold difference in serum concentration of the biomarkers (between E and C groups) was significantly greater in females than males, even though males had higher baseline concentrations of all these biomarkers.

Conclusion

When females are oestrogen-deficient, their systemic response to periapical lesions is significantly greater than males, suggesting that oestrogen is essential in protecting females from the effects of this type of inflammation.     

A longitudinal study comparing scaling, osseous surgery and modified Widman procedures. Results after one year

The purpose of this study was to compare, longitudinally, the effectiveness of scaling and root planing, osseous surgery, and the modified Widman procedures. The study was carried out in a private practice setting. Sixteen adult patients with moderate to advanced adult periodontitis were treated with initial scaling and oral hygiene procedures. Posthygiene data were used for comparison of changes in probing depth, clinical attachment levels and gingival recession. The initial examination data were used to compare changes in plaque and gingival indices. Frequency distributions were used to compare changes that occurred at individual sites. At one year, plaque and gingival indices were significantly reduced when compared with the initial examination. At one year, shallow pockets (1-3 mm) were reduced when compared to posthygiene. Four- to six-millimeter pockets were significantly reduced by the three procedures. Osseous surgery and modified Widman had significantly greater pocket reduction when compared with scaling. For pockets greater than 7 mm, osseous surgery and the modified Widman had significantly greater reduction when compared with scaling. For pockets 1-3 mm at one year osseous surgery had significantly greater clinical attachment loss when compared with scaling. For 4-6 mm pockets at one year, the three procedures had slight gains in clinical attachment levels. The results were similar for pockets with greater than 7 mm. Interproximal soft tissue craters were measured for six postoperative weeks. Initially, the modified Widman had a higher percentage of soft tissue craters when compared with osseous surgery. At six weeks, however, there were no significant differences when the surgical procedures were compared. Recession was measured at each examination. Recession for 1-3 mm pockets at one year was greater for osseous surgery when compared with scaling and the modified Widman. Recession for 4-6 mm and greater than 7 pockets was greater for the surgical procedures than scaling. The results from this study indicate that with three-month maintenance recalls, both the modified Widman and osseous surgery are effective for pocket reduction, and each will produce a slight gain of clinical attachment over one year. Scaling was effective at maintaining attachment levels but was not as effective in reducing pocket depth.     

Orientation of gingival fibroblasts in simulated periodontal spaces in vitro containing collagen gels

The present study examined the orientation of cultured human gingival fibroblasts in simulated periodontal spaces in vitro containing three dimensional hydrated collagen gels. Extracted human teeth were root planed followed by root resection and root canal instrumentation. The middle and cervical thirds of each root were cut transversely to create 600-micron thick sections. Cortical bovine bone was cut, sectioned, and contoured to create bone rings 600 micron thick with an internal diameter large enough to accommodate a root slice leaving a circumferential space varying from approximately 0.1 to 1.0 mm. Root slices and bone rings were incubated in an enzyme solution to remove all remaining soft tissues and then completely demineralized in EDTA (18%) for 72 hours. Human gingival fibroblasts (HGF) were plated to confluency in tissue culture dishes. The dentin slices were then gently placed over the HGF monolayer along with bone rings around them to create simulated periodontal spaces. Five days later, when initial cell attachment to the dentin and root slices had occurred, a collagen gel was poured in the space. The cultures were maintained for six weeks and were then processed for transmission electron microscopy. The HGF appeared to have formed multilayered cell sheets extending from the periphery of the root slices to the inner surface of bone rings. The HGF had apparently attached to both the bone and root surfaces. There was a close interaction of cells with the matrix fibrils of the gel. The cells and matrix fibrils were oriented parallel to each other.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fracture resistance of teeth restored with class II bonded composite resin

The purpose of this study was to determine whether composite resin bonded to enamel or to both enamel and dentin can increase the fracture resistance of teeth with Class II cavity preparations. Extracted maxillary pre-molars with MOD slot preparations were restored with composite resin bonded to enamel (P-30 and Enamel Bond) or composite resin bonded to enamel and dentin (P-30 and Scotch-bond). Teeth in a control group were prepared but left unrestored. All teeth were loaded occlusally in a universal testing machine until they fractured. Means of forces required to fracture teeth in each of the three groups were statistically compared (one-way ANOVA and Bonferroni t test). Teeth restored with combined enamel- and dentin-bonded composite resins were significantly more resistant to fracture than were similarly prepared but unrestored teeth and also than teeth restored with enamel-bonded composite resin (p less than 0.05). A significant difference was not demonstrated between the enamel-bonded group and the unrestored group. Further testing is needed to determine the durability of the bonds between tooth and restoration in the clinical setting.     

Influence of salivary pellicle formation time on enamel demineralization – an in situ pilot study

This study assessed the protective potential of salivary pellicles formed in situ over periods ranging from 2 to 24 h. Pellicles were produced on enamel slabs mounted on the palatal aspect of removable acrylic splints and exposed to the oral environment in three subjects for 2, 6, 12 and 24 h. Enamel specimens with and without pellicles were immersed in citric acid (1%) for 60 s, and the amount of dissolved calcium was measured by atomic absorption spectroscopy. In addition, specimens were processed for transmission electron microscopy (TEM). Mean values (standard deviations) for calcium release (mg/l related to the specimen's surface area of 5×5 mm²) were: 2-h pellicle 6.94 (1.55); 6-h pellicle 6.69 (2.05); 12-h pellicle 6.57 (2.31); 24-h pellicle 5.71 (2.46); enamel without pellicle 8.95 (1.66). There were no significant differences in calcium release that were dependent on pellicle formation time, but in comparison to enamel specimens without pellicle, significantly less (p <0.05) demineralization of the enamel was observed in pellicle-covered specimens. TEM showed that the pellicle was partly, but not completely dissolved following acid exposure. It is concluded that even a 2-h in-situ-formed pellicle layer protects the enamel surface to a certain extent against demineralization.     

Molar incisor hypomineralization: a questionnaire inventory of its occurrence in member countries of the European Academy of Paediatric Dentistry (EAPD)

Objectives. The objectives were to find out whether hypomineralized permanent first molars and incisors, known as Molar Incisor Hypomineralization (MIH), occurs all over Europe, whether its prevalence in each country is known and whether or not it is considered to be a clinical problem. Sample and methods. Clinical photos of MIH and a five‐item questionnaire were sent to members of the European Academy of Paediatric Dentistry (EAPD). A total of 59 questionnaires were sent to members in 31 countries. After one month a reminder was sent to non‐responders. Results. Fifty‐four dentists (92%) in 30 countries (97%) returned the questionnaire. MIH was stated to occur in all but one country (the Czech Republic). Nearly all the responders (97%) stated that they were familiar with the clinical appearance of MIH and a majority saw it as a clinical problem. Furthermore, a large majority of the responders (90%) considered it important to map the prevalence of MIH in European countries as such data are available to only a limited extent. Conclusion. Paediatric dentists in Europe are aware of MIH and the majority consider it to be a clinical problem. Only limited data are available on the prevalence of MIH. Comparable and representative prevalence studies are therefore urgently needed to gain more knowledge about the magnitude of MIH and related clinical problems.