Root trunk height as a risk factor for periodontal furcation involvement in maxillary first molars: an in vitro study

The aim of this study was to correlate the root trunk height from the furcation openings on the buccal, mesial and distal surfaces to the cemento-enamel junction in upper first permanent molars in human beings with risk for periodontal disease progression. One hundred extracted maxillary first molars were used. Reference points and demarcations were determined from the entrance of the buccal (F1), mesial (F2) and distal (F3) furcations to the cemento-enamel junction in millimeters. The mean distances found were 3.50 mm, 4.44 mm and 4.26 mm for the buccal, mesial and distal furcations, respectively, in relation to the cemento-enamel junction. The statistical analyses were Student's t-test and Chi-square (X2). With periodontal disease progression, the buccal furcation presents a greater compromising risk due to its proximity to the cemento-enamel junction, while the mesial furcation is the most distant, comprising a lesser risk.

Restoration interface microleakage using one total-etch and three self-etch adhesives

This study evaluated the efficacy of a total-etch and three self-etch adhesives in reducing microleakage after three months water storage and thermocycling. Thirty freshly extracted caries-free human premolars and molars were used. Class V standardized preparations were performed on the facial and lingual surfaces, with the gingival margin placed 1 mm below the CEJ. The teeth were randomly divided into four groups; Group I: Xeno III one-step self-etch adhesive (Dentsply/Caulk), Group II: Prime & Bond NT total-etch adhesive (Dentsply/Caulk), Group III: i-Bond one-step self-etch adhesive (Heraeus Kulzer) and Group IV: Clearfil SE Bond two-step self-etch adhesive (Kuraray Medical). The teeth were restored using 2 mm increments of shade A2 resin composite (Esthet-X, Dentsply/Caulk). Each layer was cured using the Spectrum 800 curing light (Dentsply/Caulk) for 20 seconds at 600mW/cm2. The teeth were stored in distilled water for 90 days. Samples were thermocycled 500x between 5 degrees C and 55 degrees C with a dwell time of 30 seconds, then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margins under a stereomicroscope at 20x magnification. Dye penetration was scored: 0 = no penetration; 1 = partial dye penetration along the occlusal or gingival wall; 2 = dye penetration along the occlusal or gingival wall; 3 = dye penetration to and along the axial wall. A Mann-Whitney test was used to demonstrate significantly more dye penetration in Group III than in the other groups at both the occlusal and gingival scores (p < 0.0001). When comparing the occlusal and gingival scores for each group, the Wilcoxon Rank test showed no significant difference in dye penetration for Xeno III (p > 0.05), Prime & Bond NT (p = 0.059) and I Bond (p = 0.083), and Clearfil SE Bond yielded more dye penetration at the occlusal than at the gingival wall (p = 0.001).

Four-year results of a prospective-controlled clinical study evaluating healing of intra-bony defects following treatment with an enamel matrix protein derivative alone or combined with a bioactive glass

AIM

To evaluate the 4-year results following regenerative periodontal surgery at intra-bony defects with either a combination of an enamel matrix protein derivative (EMD) and a bioactive glass (BG) or with EMD alone.

METHODS

Twenty-five patients with one deep intra-bony defect each were randomly treated with either an EMD+BG (test) or with EMD alone (control). Measurements were recorded at baseline, at 1 and at 4 years following therapy. The primary outcome variable was the clinical attachment level (CAL).

RESULTS

The test group demonstrated a mean CAL change from 10.3+/-1.6 to 6.7+/-1.2 mm (p<0.001) and to 6.9+/-1.0 mm (p<0.001) at 1 and 4 years, respectively. No statistically significant differences were found between the 1- and 4-year results. The control group showed a mean CAL change from 10.4+/-1.6 to 6.7+/-1.1 mm (p<0.001) at 1 year and 7.0+/-0.9 mm (p<0.001) at 4 years. The CAL change between 1 and 4 years did not present statistically significant differences. In each of the two groups, four defects have lost 1 mm of the CAL gained at 1 year. A CAL gain of 1 mm compared with the 1-year results was measured in only one defect of the test group. Compared with baseline, a CAL gain of >/=3 mm was found at 4 years in 10 defects in both groups. Between the treatment groups, no statistically significant differences in any of the investigated parameters were observed at 1 and at 4 years.

CONCLUSIONS

Within their limits, the present results indicate that the clinical improvements obtained with both regenerative modalities can be maintained over a period of 4 years.

Clinical and scanning electron microscopic features of invasive cervical resorption in a maxillary molar

This case report presents clinical and morphological features of severe invasive cervical resorption (ICR) involving a maxillary first molar. Surface morphology of the ICR defect that extended into enamel was studied using a scanning electron microscope. The topography and morphology of resorbed enamel and pulpal surfaces are described. The pulpal space was characterized by proliferation of fibrovascular tissue invaded by a number of > or = 15-microm-large dentinoclastlike cells. The vertical orientation and hexagonal geometric outlines of enamel rods indicated that the resorptive defect had extended into the outer surface of enamel. Preferential odontoclastic dissolution of interprismatic enamel was noted. Deposits of a cementumlike substance were noticed on enamel surfaces, indicating that resorptive process was coupled with repair. Complete destruction of dentin was associated with no response by the tooth to cold stimulus, supporting the hydrodynamic theory of dentinal sensitivity. The results of this study indicate that in addition to predentin and cementum, the outer surface enamel may be resistant to the resorptive process as well.

Periodontal Surgery and Glass Ionomer Restoration in the Treatment of Gingival Recession Associated With a Non-Carious Cervical Lesion: Report of Three Cases

BACKGROUND

Buccal gingival recession is a prevalent problem in populations with a high standard of oral hygiene and is very often associated with a non-carious cervical lesion, complicating treatment. The purpose of this report is to show three cases treated by an integrated periodontal and restorative dentistry approach.

METHODS

Three patients with Miller Class I gingival recessions associated with non-carious cervical lesions were enrolled for treatment. One patient received a coronally positioned flap and a resin-modified glass ionomer restoration, and two patients were treated with a coronally positioned flap, resin-modified glass ionomer restoration, and connective tissue graft. Probing depth (PD), relative gingival recession (RGR), and clinical attachment level (CAL) were measured at baseline and at 6 and 8 months after surgery.

RESULTS

After the healing period, all patients showed CAL gain and reduction in RGR. No difference was observed on PDs compared to baseline. No signs of gingival inflammation or bleeding on probing were seen. The patients were satisfied with the final esthetics and had no more dentin hypersensitivity.

CONCLUSION

This report indicates that teeth with Miller Class I gingival recessions associated with non-carious cervical lesions can be successfully treated by an integrated periodontal and restorative dentistry approach; however, longitudinal randomized controlled clinical trials must be performed to support this approach.

Is the Resorption External or Internal?

Resorption of teeth is reviewed from a diagnostic perspective to clarify the confusion as to whether it is external or internal. The key features of the various types (external surface, transient apical breakdown, external inflammatory, external replacement, external cervical and internal) are described and illustrated by cases. Management and appropriate treatment is dependent on the correct diagnosis.

CLINICAL RELEVANCE

Diagnosis of resorption is essential to the appropriate management.

Invasive cervical resorption: a case report

Invasive cervical resorption (ICR) is a relatively uncommon form of external resorption, which may occur in any tooth in the permanent dentition. Characterized by its cervical location and invasive nature, this resorptive process leads to progressive and usually destructive loss of the tooth structure, the clinical features of which often resemble internal resorption ("pink tooth"). This article describes a case report of ICR and its management. The salient features were a large resorptive defect and localized fibrous in-growth located almost wholly on the cervicolabial aspect of the maxillary incisor crown involving the enamel and dentin.

Management of tooth resorption

A correct diagnosis and an understanding of the aetiology and dynamics of the processes involved in tooth resorption is critical to effective management. Tooth resorptions can be classified as: (1) trauma induced; (2) infection induced; or (3) hyperplastic invasive. Some transient trauma induced resorptions require no treatment but must be carefully monitored to check that there are no complicating issues such as infection. In cases of trauma induced replacement resorption, a multidisciplinary approach is usually necessary to ensure an optimal long-term solution. Infection induced tooth resorptions require the removal of the invading micro-organisms by endodontic therapy including intra-canal medication which can also facilitate repair of the resorbed tooth structure. The hyperplastic invasive tooth resorptions pose considerable challenges in management due to the complexity and aggressive nature of the resorptive process. With careful case selection and complete inactivation of resorptive tissue successful management can be achieved.

Rationale and protocol for the treatment of non-cavitated smooth surface carious lesions

The decision to restore a smooth surface carious lesion should be based on whether the lesion has cavitated. All non-cavitated lesions should receive preventive therapy aimed at arresting and remineralizing the lesion. Dental caries is a disease based on an imbalance in the equilibrium of ion exchange between the tooth and dental plaque, resulting in a net mineral loss. This equilibrium often can be reversed prior to cavitation, eliminating the need for treating the tooth surgically. Dentists in the U.S. often are apt to restore all lesions that have radiographically penetrated the dentinoenamel junction; however, most of these lesions have not cavitated and can be treated with preventive therapy. Restorations have a limited lifespan and the preparation is enlarged every time a restoration is replaced; as a result, a surgical approach can lead to unnecessary removal of tooth structure and eventually lead to more extensive treatment such as root canal therapy. This article reviews the rationale for deciding when to restore or remineralize non-cavitated lesions on the smooth tooth surfaces in the permanent dentition (and when to provide no treatment at all), what preventive treatment should be administered, and how to determine if the disease has been arrested.

Cuspal deflection and microleakage in premolar teeth restored with resin-based composites with and without an intermediary flowable layer

OBJECTIVES

To assess cuspal deflection and cervical enamel microleakage with and without an intermediary flowable RBC layer for the incremental restoration of mesio-occluso-distal (MOD) cavities with two resin-based composites (RBCs).

METHODS

Forty sound upper premolar teeth had standardised MOD cavities prepared. Restoration of the teeth involved the placement of the RBCs (Filtek P60 or Filtek Supreme) in eight increments with the appropriate bonding system with and without an intermediary flowable RBC layer (Filtek Flow). Buccal and palatal cusp deflections were recorded post-irradiation using a twin channel deflection measuring gauge. Following restoration, the teeth were thermocycled, immersed in a 0.2% basic fuchsin dye for 24h, sagittally sectioned and examined for cervical enamel microleakage.

RESULTS

A significant reduction in cuspal deflection was evident when both RBC materials were used to restore the cavity by employing an intermediary flowable (P<0.001) compared with when no intermediary flowable was utilised. No statistically significant differences were identified in microleakage between the teeth restored with Filtek P60 or Filtek Supreme when an intermediary flowable (Filtek Flow) was employed.

CONCLUSIONS

The results of the current study suggest that there was a benefit to the operator in terms of a reduction in cuspal deflection but not from the maintenance of the synergism of the adhesive bond, namely microleakage at the cervical enamel cavosurface margin, when an intermediate layer of a flowable RBC was used under higher elastic modulus RBCs.

Gingival seal of deep Class II direct and indirect composite restorations

PURPOSE

To evaluate in vitro the gingival microleakage of Class II direct and indirect composite restorations with cervical margins 0.5 mm apical to the cemento-enamel junction (CEJ).

METHODS

Mesial-occusal (MO) preparations of similar size were made in 10 homologous pairs of caries-free extracted human third molars. One specimen for each pair was prepared for a direct composite restoration and the other for an indirect composite restoration. Direct preparations were restored per manufacturer's instructions. Indirect preparations were impressed, and composite restorations were fabricated and cemented with a dual-cure cement. A total-etch technique was used for all restorations. Restorations were finished, polished, stored for 1 week in distilled water at 37 degrees C, thermocycled (5 degrees-55 degrees C x 1000), sealed with fingernail polish (leaving a 1.5 mm open periphery adjacent to the gingival margin), and placed in 0.5% basic fuchsin dye for 24 hours. Teeth were sectioned longitudinally (mesio-distally) within the restoration in two cuts and the four resulting surfaces (two inner cut surfaces, two outer cut surfaces) were evaluated for dye penetration with a x10 stereoscope using a scale of 0 (no penetration) to 4 (dye penetration involving more than half the axial wall).

RESULTS

All 20 specimens had at least one score of three (dye penetration involving less than half of the axial wall) or four. Statistical analysis (Wilcoxon paired-sample test) disclosed a significant decrease in the indirect composite microleakage scores for the two outer cuts (P = 0.006, P = 0.002). No significant differences in microleakage scores were found between materials for the inner cut surfaces of the specimens. Overall, the results of die penetration showed no statistical difference between Class II direct and indirect composite restorations for microleakage.

A Familial Pattern of Multiple Idiopathic Cervical Root Resorption in a Father and Son: A 22-Year Follow-Up

BACKGROUND

The etiology of idiopathic cervical root resorption has not been elucidated clearly. However, the process has been linked to trauma, intracanal bleaching, and partial-thickness connective tissue grafts.

METHODS

This study describes a familial pattern of multiple idiopathic cervical root resorption in a father and son.

RESULTS

The father was a healthy 63-year-old white male who presented with the first resorption lesion in 1983. Twenty-seven additional lesions were identified on 16 teeth over 22 years. Five teeth were lost as a result of extensive resorption. The son was a healthy 43-year-old when a resorption lesion was identified in 1993. A lesion identified on another tooth 12 years later resulted in extraction.

CONCLUSIONS

Close relatives of those affected by multiple idiopathic cervical root resorption should be examined carefully for cervical resorption. This study also showed that early treatment can prevent or delay the need for extraction.

Specific caries index: A new system for describing untreated dental caries experience in developing countries

OBJECTIVES

To develop a reproducible surface-specific caries index that provided qualitative and quantitative information about untreated dental caries, that could be used in conjunction with the DMFS index and would provide information on not only the caries prevalence but also the location and type of caries lesion in an individual based on clinical examination.

METHODS

Untreated carious lesions were divided into six types based on the location of the lesions. 339 rural school children in the age group of 12-15 years were examined for dental caries using both the DMFS index and the Specific Caries Index.

RESULTS

Type 1 and 2 were found to be the most common type of caries lesions. The reproducibility of the Specific Caries Index was also found to be good.

CONCLUSIONS

Encouraging indications about the validity and reproducibility of this new caries index was found, suggesting the need for further studies to test its applicability in larger and different populations.

Marginal bone levels measured in film and digital radiographs corrected for attenuation and visual response: anin vivostudy

OBJECTIVE

To compare the accuracy and precision of measurements on marginal bone levels in differently processed digital radiographs and in film-based radiographs.

METHODS

Twenty-one patients with a diagnosis of chronic periodontitis were included in this study. Periapical radiographs were exposed with the Dixi digital intraoral radiographic system (Planmeca Oy, Helsinki, Finland) and the F-speed Film (Insight, Eastman-Kodak Co., Rochester, NY), respectively. Digital radiographs were subsequently processed into two sets: (a) correction for attenuation and visual response and (b) the same correction but with an additional shift in grey levels. Patients had periodontal surgery immediately after the radiographs were exposed. The vertical distance from cementoenamel junction to the most apical part of the marginal bone was assessed. The measurements were then employed as reference standard and subtracted by the vertical distance from radiographs accordingly. Altogether, 47 sites were evaluated. Seven observers were employed for evaluation under the same viewing conditions. ANOVA was employed for statistical analysis.

RESULTS

No significant differences were found between the absolute differences of the vertical distance obtained from radiographs to their corresponding reference standards when comparing differently processed digital radiographs, but the absolute differences were significantly smaller in digital radiographs than in films. Interobserver variances were not significant.

CONCLUSION

Digital radiographs have a favourable measurement accuracy compared with film radiographs when assessing marginal bone levels.

The prevalence of dentine hypersensitivity among adult patients attending a Nigerian teaching hospital

PURPOSE

The purpose of this study was to determine the prevalence of dentine hypersensitivity and to examine some associated factors such as initiating stimuli among adult patients attendingthe Dental Clinic of the Obafemi Awolowo University Teaching Hospital, Ile-Ife, Nigeria.

MATERIALS AND METHODS

All consecutive adult patients that presented at the oral diagnosis unit over a period of 13 months, from March 2003 to March 2004, were included in the study. Relevant history, such as nature of the pain, initiating stimulus, frequency of episode, interference with eating, drinking and toothbrushing were taken. Evidence of tooth surface loss was noted. Dentine hypersensitivity was confirmed clinically by the use of air blast from the air-water jet and scratching suspected surfaces with a dental probe.

RESULTS

Of the 2165 patients examined, 29 were diagnosed as having dentine hypersensitivity, giving a prevalence figure of 1.34%. The commonest teeth affected were the molars and the commonest initiating factor was cold water. Occlusal surfaces were most affected, followed by cervical surfaces. A male predominance was observed.

CONCLUSION

A lower prevalence figure was found in the present study in comparison to earlier reported studies. The prevalence of dentine hypersensitivity is slightly lower in females, with female to male ratio of 1 to 1.42. Dentine hypersensitivity resulted in more severe disturbance when drinking water than when eating or brushing.

Root coverage with free gingival autografts--a clinical study

AIM

To assess the percentage of root coverage with autogenous free gingival grafts.

MATERIALS & METHODS

Ten non-smoking patients with Miller's class I or class II recessions were included in the study. The clinical parameters such as recession depth, recession width, probing pocket depth, clinical attachment level and width of the keratinized gingiva were recorded at the baseline, at the end of 1 month, 3 months, and 6 months after the surgical procedure. Autogenous free gingival grafts harvested from the palatal mucosa were used to cover the denuded roots.

RESULTS

Four out of ten sites showed 100% root coverage. A mean percentage of 80.3% of root coverage was achieved.

Clinical long-term retention of etch-and-rinse and self-etch adhesive systems in non-carious cervical lesions. A 13 years evaluation

OBJECTIVES

The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems.

METHODS

A total of 337 Class V restorations of three three-step etch-and-rinse, one two-step etch-and-rinse and three self-etch adhesive systems were placed in non-carious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline and then every 6 months during a 13 years follow-up. Dentin bonding efficiency was determined by the percentage of lost restorations.

RESULTS

During the 13 years, 275 restorations could be evaluated. The cumulative loss rate at 13 years was 60.3%, with significant different failures rates for the different systems varying between 26.3 and 94.7%. Three materials fulfilled the ADA 18 months full acceptance criteria. Three systems showed already at 18 months or earlier catastrophical debonding rates. The annual failure rates for the three-step etch-and-rinse systems were: Allbond 2 4.1%, Clearfil LB 2.0% and Denthesive 7.3%. For the two-step etch-and-rinse Gluma 2000 6.5%, and for the self-etch systems ART 3.2%, Denthesive 2 5.7% and PUB 3 4.5%

CONCLUSION

A continuous degradation of the resin-dentin bond was observed for all bonding systems during the follow-up expressed by the increasing loss rates. A wide variation of dentin bonding effectiveness was seen between the systems independent to adhesion strategy.

Extended Bleaching of Tetracycline-Stained Teeth: A 5-Year Study

When using a tray delivery technique, tetracycline-stained teeth can be effectively lightened with the extended use of tooth whiteners. Cervical staining is the most difficult area to lighten.

5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions

AIM

To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions.

METHOD AND MATERIALS

One operator placed 70 restorations (35 resin modified glass ionomer restorations and 35 resin composite restorations) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by 2 independent examiners, using modified USPHS criteria at baseline and 6, 12, 24 and 60 months.

RESULTS

Twenty-two patients were available for recall after 5 years (73.3% recall rate) and 55 out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (kappa > or = 0.85). Sixteen composite restorations were dislodged (51.5% retention) and 1 ionomer restoration was lost (96.4% retention). The McNemar test detected significant differences in resin composite restorations between baseline and 5-year recall for marginal integrity (p<0.001) and retention (p=0.004). For resin modified glass ionomer restorations, no significant differences were identified for all criteria (p>0.05). When comparing both materials, the Fisher exact test pointed out significant differences in retention (p=0.002) after 5 years of clinical service.

CONCLUSIONS

After 5 years of evaluation, the clinical performance of resin modified glass ionomer restorations was superior to resin composite restorations.

Complicated Root Canal Morphology of Mandibular First Premolar in a Chinese Population Using the Cross Section Method

The purpose of this study was to assess the canal anatomy and morphology of mandibular first premolars in a Chinese population. Eighty-two extracted mandibular first premolars with intact roots were collected and stored in a glutaraldehyde solution. The teeth were embedded in clear resin and the root length was measured. The roots were resected perpendicular to the long axis at 3, 6, 9, and 12 mm from the apex. The resected root surfaces were polished, rinsed, dried, and stained with methylene blue. Digital photographs of the cross-sectional root surfaces were made at 24X. The incidence of multiple canals and varied morphology was determined by two independent examiners. The results indicated that 54% of the mandibular first premolars demonstrated a single canal. Twenty-two percent contained two canals and 18% percent had C-shaped configuration. The C-shaped root canal occurred predominantly in the 3 and 6 mm sections with one or two canals coronally. A unique finding was the circumferential canal (apical delta), which was characterized by a single canal splitting into 3 or 4 canals. The incidence of circumferential canal was 6% and occurred only in the apical 3 mm cross-sections. Identification of this unique apical canal configuration and the high incidence of multiple canals in mandibular first premolars may explain endodontic treatment failure in this tooth group.

[Micro-tensile bond strength to sclerotic dentin in non-carious cervical lesions]

OBJECTIVE

This in vitro study was to evaluate the micro-tensile bond strength (microTBS) of three adhesives to sclerotic dentin in non-carious cervical lesions.

METHODS

The maxillary premolars extracted due to periodontitis and with non-carious cervical lesions were collected. The non-carious, natural cervical sclerotic lesions were bonded with a total-etching adhesive Scotchbond Multi-Purpose, a two-step self-etching adhesive Contax, and an all-in-one self-etching adhesive Adper Prompt L-Pop. Artificially prepared wedge-shaped lesions were also made in sound premolars and bonded with the same adhesives as the controls. MicroTBS of these three adhesives was measured.

RESULTS

MicroTBS of Scotchbond and Contax to sclerotic dentin was significantly lower than to normal dentin. But microTBS of Adper Prompt L-Pop to normal dentin was significantly lower than to sclerotic dentin. MicroTBS to sclerotic dentin was Scotchbond 46.805 MPa, Adper Prompt L-Pop 39.045 MPa, and Contax 29.852 MPa.

CONCLUSIONS

In sclerotic dentin the microTBS was decreased because of the inferior micro-morphology of resin tags. Adhesives with low pH value might bond to sclerotic dentin effectively.

Symmetry of non-carious cervical lesions in canines and premolars

OBJECTIVES

Clinically non-carious cervical lesions (NCCLs) are frequently seen. The aim of this study was to investigate the relationship between the shape and symmetry of NCCLs, wear of cuSPS and triangular ridge, and the curvature of the tooth root.

METHODS

One hundred and twenty-nine extracted human upper canine teeth and 274 extracted human upper premolar teeth with NCCLs were used in this study. The specimens were studied using photographs and three-dimensional scanning.

RESULTS

Asymmetric NCCL was observed in 69.0% of the canines and 44.5% of the premolars. Wear of cusp and lingual ridges was observed in 82.9% and 93.0% of the canines, respectively. Wear of the buccal cusp and buccal triangular ridge was observed in 85.4% and 89.8% of the premolars, respectively. On the other hand, the wear of lingual cusp and lingual triangular ridge was observed in 89.1% and 93.8% of the premolars, respectively. The curvature of the root was observed in 48.1% of the canines and 43.4% of the premolars.

CONCLUSIONS

There was no relationship between the symmetry of NCCLs, and the wear of cuSPS and triangular ridges for either canines or premolars. Although there was a relationship (p < 0.05) between the symmetry of NCCL and the curvature of the root in the canines, no relationship was observed between the symmetry of NCCL and the curvature of the root in the premolars.

External invasive resorption in a three-rooted lower first molar*

Several pathoses can be present concurrently in one tooth, and if that tooth has an unusual anatomical variation, the diagnosis and treatment can be further complicated. This case stresses the importance of accurate assessment and diagnosis prior to intervention and their role in identifying cases for referral to a specialist in today's increasingly litigious environment.

Retention of restorations placed in noncarious cervical lesions after centric and eccentric occlusal loading in a chewing simulator--A pilot study

PURPOSE

To evaluate in a pilot study whether (1) loading of restored teeth in a chewing simulator is an adequate method to reproduce clinical data about the retention rate of restorations placed in noncarious cervical lesions by means of the one-step self-etching adhesive system Prompt-L-Pop, and (2) whether eccentric loading contributes to the loss of Class V fillings.

MATERIALS AND METHODS

In 12 extracted mandibular premolars with noncarious buccal cervical lesions of similar dimensions, restorations were placed without preparation using Prompt-L-Pop and Tetric Ceram. The adhesive was applied in one layer and cured at 650 mW/cm2 for 10 s, while the composite was placed in two increments and cured at 1200 mW/cm2 for 10 s. After storage in water at 37 degrees C for 7 days, the teeth were mounted in a chewing simulator that uses pneumatic cylinders as force actuators and subjected to a centric load of 50 N and 1,200,000 load cycles at a frequency of 1.6 Hz and simultaneously to 3125 thermocycles (5 degrees C/55 degrees C). The antagonists were standardized and made of Empress ceramic material. Every 100,000 load cycles, the fillings were evaluated with regard to retention. In the second phase, the same teeth were loaded on the lingual cusps with new antagonists for another 1,200,000 cycles.

RESULTS

Neither during centric nor eccentric loading was any restoration loss observed.

CONCLUSION

The short-term loading of extracted teeth with Class V fillings in a chewing simulator was inadequate to reproduce the data of clinical studies on the retention rate of a self-etching adhesive system. Obviously, long-term degradation mechanisms (eg, hydrolysis) acting on the composite/dentin interface play a more crucial role when it comes to the loss of retention of Class V restorations. Eccentric loading alone did not contribute to the loss of fillings, so that the theory--which maintains that this type of occlusal stress is a major cause for abfractions or the retention loss of restorations placed in abfraction lesions--may be questioned.

Clinical and anatomical factors limiting treatment outcomes of gingival recession: a new method to predetermine the line of root coverage

Complete root coverage is not always achievable, even in gingival recession with no loss of interproximal attachment and bone. The cemento-enamel junction is the most widely used referring parameter to evaluate root coverage results. The aim of the present study was to describe the most frequent diagnostic mistakes that may lead to incomplete root coverage in Miller Class I and II gingival recessions and to suggest a method to predetermine the level/line of root coverage in non-molar teeth. The line of root coverage (i.e., the level/line to which the soft tissue margin will be positioned after the healing process of a root coverage surgical technique) was predetermined by calculating the ideal vertical dimension of the interdental papilla of the tooth with the recession defect. This method was applied to 120 recession-type defects affecting non-molar teeth of 80 young healthy subjects that were treated with root coverage surgical procedures over the last 5 years. All recessions were Miller Class I or II and were associated with at least one of the following characteristics: 1) traumatic loss of the tip of the interdental papilla(e); 2) tooth rotation; 3) tooth extrusion with or without occlusal abrasion; and 4) a cervical abrasion defect with no evidence of the cemento-enamel junction. The line of root coverage may be considered the clinical cemento-enamel junction because it may substitute the anatomic cemento-enamel junction when this is no longer clinically visible on the tooth with recession or when the ideal conditions to obtain complete root coverage are not fully represented.

Reducing the bias of probing depth and attachment level estimates using random partial-mouth recording

OBJECTIVES

To evaluate the bias and precision of probing depth (PD) and clinical attachment level (CAL) estimates of random and fixed partial examination methods compared with full-mouth examinations.

METHODS

PD and CAL were calculated on six sites for up to 28 teeth (considered to be the gold standard with no bias) and three fixed-site selection methods (FSSMs) that resulted in a partial examination of sites: the Ramfjord method, and the NIDCR methods used in NHANES I, and NHANES 2000. Finally, seven random-site selection methods (RSSMs) were created by sampling the following number of sites: 84, 42, 36, 28, 20, 15, 10 and 6. To compare bias and precision of the methods we calculated percent relative bias and relative error.

RESULTS

Estimates of means, standard deviations (SD), relative bias and relative error for RSSMs were almost identical to the full-mouth examination, but SDs increase slightly when fewer than 28 sites were sampled and relative bias and error increase for methods sampling fewer than 20 sites. The FSSMs had very low relative error, but much higher relative bias indicating underestimation. The FSSM with the smallest bias and error was the Ramfjord method, but the Random 36 method had less bias and less relative error. The NHANES 2000 method was the FSSM with the lowest bias and relative error for estimates of Extent Scores (percent of sites > or =3, 4, 5, or 5 mm PD or CAL) but random methods sampling fewer sites performed just as well. Both FSSMs and RSSMs underestimated prevalence, especially prevalence of less frequently occurring conditions, but most RSSMs were less likely to underestimate prevalence than the FSSMs.

CONCLUSION

The promise of reducing bias and increasing precision of the estimates support the continued development and examination of RSSMs.

[Effect of acid etching time on bonding interface of non-carious cervical sclerotic dentin]

OBJECTIVE

To examine the effect of acid etching time on the bonding interface of non-carious cervical sclerotic dentin.

METHODS

Twenty extracted premolars with non-carious cervical lesions were randomly divided into two groups, the lesion surface was conditioned with Scotchbond Multi-Purpose Plus dentin bonding system. The etching time was 15 s and 30 s respectively. The bonding interface ultrastructures were compared with SEM.

RESULTS

In sclerotic dentin (15 s), the hybrid layer was visible, with minimal resin tags in the dentinal tubules and, when presented, they were shorter. Doubling the etching time (30 s) resulted in more resin tags with an hybrid layer formation on peritubular dentin.

CONCLUSION

Doubling the etching time improved the ultrastructure of sclerotic dentin-resin bonding interface, and could be an efficient way to improve the bonding effect.

A proposal for a new classification of lesions of exposed tooth surfaces

In the presence of improved methods of identification and treatment of lesions on the exposed surfaces of teeth, it should now be acknowledged that the GV Black "classification of carious cavities" is out of date. This paper describes a new system, proposed in 1997, discussed broadly throughout the profession, and eventually modified. The system has been adopted in several regions around the world as being a useful corollary to the current developing concept of minimal intervention dentistry. It is now desirable to adopt a new approach to the identification and recording of the lesions caused by both caries and non-carious tooth loss. A major advantage arising from its adoption would be that it would encourage the profession to minimise the amount of normal healthy tooth structure that is often sacrificed in pursuit of the cavity designs as suggested by Black. The authors are members of a Project Group of the FDI Science Committee, and this paper explains the concept and offers justification for the adoption of the system.

Digital moiré interferometric investigations on the deformation gradients of enamel and dentine: an insight into non-carious cervical lesions

OBJECTIVES

The objective of this study was to evaluate the biomechanical basis of non-carious cervical lesions by examining the patterns of deformation (strain) in the enamel and dentine.

METHODS

The digital moiré interferometry is optics based non-destructive, whole-field experimental technique that provides whole-field strain information. Diffraction gratings (with a frequency of 1200 lines/mm) were transferred onto sagittal sections of human teeth, which were subsequently loaded compressively for loads ranging from 10 to 200 N at the incisal edge of the tooth. The acquired digital moiré fringe patterns were used to determine the in-plane deformation pattern in the enamel and the dentine in the direction parallel to the long axis (axial direction) and in the direction perpendicular to the long axis (lateral direction) of the tooth.

RESULTS

It is observed that the enamel displayed marked strain gradients in the lateral direction, while the coronal dentine experienced marked strain gradients in the axial directions during compression. With the increase in applied loads, the strains in the enamel increased at the cervical edge (above the cemento-enamel junction) on the facial side, while the strains in the dentine increased below the cemento-enamel junction on the facial side.

CONCLUSION

The enamel and dentine displayed unique in-plane deformation patterns in the axial and the lateral directions of the tooth. These experiments support the hypothesis that occlusal loading will contribute to cervical loss of dental hard tissues.

A case of multiple idiopathic external root resorption: a 6-year follow-up study

Multiple idiopathic external root resorption of permanent teeth is a very infrequent phenomenon. This paper describes a case of multiple idiopathic external root resorption at cement-enamel junction in 21 of 25 teeth followed up for 6 years. In addition to clinical features and radiographs, we present results of histological and bacteriological examinations.

Soft tissue management for difficult cervical restorations

This article offers a rationale for choosing methods of isolation and soft tissue management that will result in the best possible operating conditions for treating cervical dental lesions. A surgical technique used in conjunction with rubber dam isolation is described for those Class V lesions that cannot be managed effectively in a routine manner.

Noncarious cervical lesions in adults: prevalence and occlusal aspects

BACKGROUND

The factors that induce the formation of noncarious lesions are not understood fully, particularly those that are related to occlusal aspects. The authors conducted a study to evaluate the prevalence of noncarious cervical lesions in adults and their association with occlusal aspects.

METHODS

The authors examined 70 people (35 men and 35 women) aged 25 to 45 years to determine the presence and type of noncarious cervical lesions, wear facets, tooth contacts in maximal intercuspal position, and lateral and protrusive movements. The assessment involved a questionnaire and clinical examination.

RESULTS

Among the teeth the authors evaluated, 17.23 percent had cervical lesions, 80.28 percent of which had wear facets (P < .01). The authors found a significant difference between the prevalence of noncarious lesions and the presence of wear facets (P = .0484).

CONCLUSIONS

The authors found that cervical lesions were related significantly to wear facets. These findings strengthen evidence for the role of occlusal forces as an etiologic factor for noncarious lesions.

CLINICAL IMPLICATIONS

The presence of wear facets should be considered in the treatment of noncarious cervical lesions.

Alveolar bone loss and aging: a model for the study in mice

BACKGROUND

Several animal studies have shown a positive correlation between aging and alveolar bone loss (ABL). The purpose of this study was to develop a model for the study of ABL in mice and aging.

METHODS

Mucoperiosteal flap surgery (MFS) was performed on the buccal aspect of the left side of the mandible (BL) in 72 CF(1) Mus domesticus mice and divided into three groups as follows: males, breeding (non-virgin) females, and virgin females. The MFS was performed in 3-, 6-, 9-, and 12-month-old animals under anesthesia. The buccal aspects of right hemimandibles were used as controls (BR). Animals were sacrificed under anesthesia 21 days after surgery. Mandibles were removed, defleshed, stained with toluidine blue, and photographed in a microscope. The photographs were digitized, and ABL was measured as the exposed root surface area (mm(2)). Blinded measurements were performed using a computer-assisted image analysis system.

RESULTS

In terms of alveolar bone loss, the BL (operated) area showed a significant difference (paired Student t test; P <0.001) when compared to the BR area in all three groups. Sex and breeding differences were not observed in this experiment. ABL in the left hemimandibles was significantly larger in 3- (mean: 0.70; 95% confidence interval [CI]: 0.59 to 0.80) and 12-month-old animals (mean: 0.58; 95% CI: 0.46 to 0.71) than in 6- (mean: 0.39; 95% CI: 0.33 to 0.46) and 9-month-old animals (mean: 0.42; 95% CI: 0.35 to 0.48); P <0.001.

CONCLUSION

The results suggest that 3-month-old CF(1) mice, in a sex and breeding independent process, could be a useful model for provoked alveolar bone loss studies in aging.

Clinical evaluation of a resin-modified glass-ionomer liner for cervical dentin hypersensitivity treatment

PURPOSE

To evaluate the effectiveness of two agents for treating cervical dentin sensitivity associated with gingival recession or noncarious cervical lesions.

METHODS

44 patients with at least mild sensitivity affecting cervical dentin were enrolled in a longitudinal randomized clinical trial. A resin-based desensitizer or an experimental glass-ionomer was assigned to treat at most two teeth from each side of the mouth. Sensitivity was assessed by tactile and cold tests, measured with a Visual Analogue Scale at baseline, after treatment, and at 1 week, 1, 3, 6, and 12 months after treatment. Other noteworthy clinical observations were recorded.

RESULTS

Both treatments effectively reduced dentin sensitivity (mixed linear model analysis). Sensitivity score for the glass-ionomer was significantly lower than for the resin-based desensitizer after treatment and at all follow-up periods (P < 0.0001). Some overhanging margins were observed in the glass-ionomer group, which could accumulate plaque and cause gingivitis. Despite material loss from some teeth treated with the glass-ionomer, the follow-up sensitivity scores were still lower than baseline scores.

Comparative Study of Two Root Coverage Procedures: A 24-Month Follow-Up Multicenter Study

BACKGROUND

Treatment alternatives to cover exposed root surfaces include free grafts, pedicle flaps, and barrier membranes. This 24-month follow-up study clinically evaluated the long-term effect of a coronally advanced flap procedure with the additional use of enamel matrix derivative (EMD) to treat gingival recession versus the subpedicle connective tissue graft (CTG) procedure.

METHODS

Miller Class I or II buccal recession-type defects in the anterior teeth or premolars in 65 patients (28 in EMD and 37 in CTG groups) were treated in several centers. At baseline and 12 and 24 months post-treatment, vertical recession defect (VRD), height of keratinized tissue (HKT), and probing depth (PD) were recorded, and the percentage of root coverage (PRC) of the original defect was calculated. Student t test, analysis of variance, and analysis of covariance were used for statistical analyses.

RESULTS

At 12- and 24-month evaluations, PRC was 73.2% (SD=15.58%) and 76.9% (SD=16.77%) in the EMD group and 86.8% (SD=12.48%) and 84.3% (SD=13.32%) in the CTG group, respectively (P<0.001). Differences between groups were statistically significant (P=0.002). Baseline HKT was 1.07 mm (SD=0.66 mm) in the EMD group and 1.65 mm (SD=0.92 mm) in the CTG group. At 12 and 24 months, values were 1.75 mm (SD=0.59 mm) and 2.25 mm (SD=0.52 mm) in the EMD group and 4.24 mm (SD=0.89 mm) and 4.05 mm (SD=0.94 mm) in the CTG group, respectively. Differences in HKT were statistically significant within (EMD: P<0.001; CTG: P=0.017) and between (P<0.001) groups.

CONCLUSIONS

Both treatments proved clinically successful. CTG treatment showed a higher percentage of root coverage and HKT increase. EMD is a valuable, long-term effective treatment alternative to achieve root coverage together with an increase in HKT.

Distal cervical caries in the mandibular second molar: An indication for the prophylactic removal of the third molar?

AIMS

Distal cervical caries (DCC) in mandibular second molar teeth are responsible for the removal of up to 5% of all mandibular third molars. Our aim was to identify the clinical features of these patients.

METHODS

We evaluated the records of 100 patients who had 122 mandibular third molars removed because of distal cervical caries in the second molar.

RESULTS

Eighty-two percent of third molars had a mesial angulation of between 40 degrees and 80 degrees. The peak age for removal of third molars was 5 years later than in other studies and patients had better dental health than average. The incidence of distal cervical caries DCC has been shown to increase with age.

CONCLUSION

Distal cervical caries is a late phenomenon and has been reported only in association with impacted third molars. The early or prophylactic removal of a partially erupted mesio-angular third molar could prevent distal cervical caries forming in the mandibular second molar.

Coronally Positioned Flap for Root Coverage: Poorer Outcomes in Smokers

BACKGROUND

Gingival recession is significantly more common among smokers, while the relative outcome of various root coverage procedures in smokers, compared to non-smokers, is debatable. The objective of this study was to evaluate the influence of cigarette smoking on the outcome of coronally positioned flap (CPF) in the treatment of Miller Class I gingival recession defects.

METHODS

Ten current smokers (> or = 10 cigarettes daily for at least 5 years) and 10 non-smokers (never smokers), each with one 2- to 3-mm Miller Class I recession defect in an upper canine or bicuspid, were treated with CPF. At baseline and 6 months, clinical parameters, probing depth (PD), clinical attachment level (CAL), recession depth (RD), and apico-coronal width of keratinized tissue (KT) were determined.

RESULTS

Intragroup analysis showed that CPF was able to reduce RD and improve CAL in both groups (P <0.05). Intergroup analysis demonstrated that smokers presented greater residual RD at 6 months and lower percentage of root coverage (69.3% versus 91.3%; P <0.05). No smokers obtained complete root coverage compared to 50% of non-smokers (P <0.05).

CONCLUSIONS

Within the limits of the present study, it can be concluded that CPF provides benefits for both smokers and non-smokers in terms of root coverage of shallow Miller Class I recession defects. However, cigarette smoking negatively impacts the clinical outcomes, specifically residual recession, percent root coverage, and frequency of complete root coverage.

Non carious cervical lesions. A review

Non-carious cervical lesions (NCCL) are characterized by a loss of hard dental tissue near the cement-enamel-junction. Commonly, their shape is like a wedge with the apex pointing inwards. Other times, they appear as regular depressions, like a dome or a cup. Their main characteristic is the presence of hard-mineralized tissue. According to the literature, the prevalence of cervical lesions is 85%, while their incidence is about 18% among permanent teeth. NCCL are currently classified as erosion, abrasion, or abfraction. Their etiology seems to be related to different factors: hexogen and endogen acids, mechanical abrasive action, tooth flexion under axial and non-axial loads. Moreover, it seems that a fundamental role is ascribable to tooth bending phenomena due to the strength components parallel or oblique to the occlusal level, which occur during the normal function as well as during parafunctions. The frequent therapeutic failures are probably due to the same factors causing the onset of the original lesion. Several materials have been proposed to restore NCCL: amalgam (abandoned), glass-ionomer cements, compomers, and composite resins. Early failures of these restorations have often been reported in the literature, probably due to the same factors which originally caused the lesions. Further investigations are required to determine more reliable restorative therapies.

Diagnosis of Erosive Tooth Wear

The clinical diagnosis 'erosion' is made from characteristic deviations from the original anatomical tooth morphology, thus, distinguishing acid induced tissue loss from other forms of wear. Primary pathognomonic features are shallow concavities on smooth surfaces occurring coronal from the enamel-cementum junction. Problems from diagnosing occlusal surfaces and exposed dentine are discussed. Indices for recording erosive wear include morphological as well as quantitative criteria. Currently, various indices are used making the comparison of prevalence studies difficult. The most important and frequently used indices are described. In addition to recording erosive lesions, the assessment of progression is important as the indication of treatment measures depends on erosion activity. A number of evaluated and sensitive methods for in vitro and in situ approaches are available, but the fundamental problem for their clinical use is the lack of re-identifiable reference areas. Tools for clinical monitoring are described.

[Analysis of etiological factors involved in noncarious cervical lesions]

PURPOSE

The etiopathology of noncarious cervical lesions (NCCL) is multifactorial and still not fully understood. Tooth wear is defined as loss of dental hard tissue by a chemical or mechanical process that does not involve bacteria. This form of tooth surface loss includes attrition, abrasion, erosion, and abfraction. Noncarious cervical lesions represent loss of tooth structure at the cementoenamel junction. The purpose of this clinical study of NCCL was to analyze the etiology in relation to age and to identify the most important risk factors associated with cervical lesions, as well as patients and teeth more susceptible to NCCL with a focus on more effective treatment of this condition.

MATERIAL AND METHODS

The study group comprised 124 patients with NCCL, aged 15-75 years (mean = 44). A questionnaire was distributed addressing medical history--gastric disorders, dietary habits--consumption of acidic drinks, dental history, oral hygiene practices, and parafunctional habits. Clinical examination of tooth wear was performed on four tooth surfaces after air-drying. The distribution and severity of tooth wear was graded using the tooth wear index (TWI) calculated with a computer programme allowing for tooth characteristic to be determined for each decade of life. Depth of the cervical defect was measured with a periodontal probe. TWI was devised to reveal the extent of tooth surface wear irrespective of the cause. Raw scores were compared with the computer using predetermined threshold values which are set to distinguish between acceptable and unacceptable pathological levels of tooth wear for each decade of life and each tooth surface. Dentition status, oral hygiene, periodontal status, gingival recession, number of teeth and their mobility, oral symptoms of parafunction and relationship to lateral and protrusive tooth contact schemes was assessed and analyzed. Statistical analyses were performed with the Stata Statistical Software: release 5. The risk of NCCL formation was estimated with the logistic regression model. Results were presented as odds ratio, 95% confidence interval, and p probability.

RESULTS

Tooth wear on all surfaces of the tooth, including cervical, was related to age and the ranges were 25-60%. Older patients were more likely to exhibit NCCL. Frequency, localization, and depth of noncarious cervical lesions in a given group of teeth was related to age, although NCCL was more common in premolars (mean = 85.1%). Associations between oral hygiene, consumption of acidic drinks, status of periodontium, number of teeth, their mobility and etiology of wedge-shaped defects were revealed. A relationship between lateral excursive contact of teeth, bruxism, and formation of cervical lesions was established evidencing a correlation between occlusal and cervical pathology.

CONCLUSIONS

1. Cervical lesions were most common in premolars. 2. Early detection of dental erosion is important for prevention of serious irreversible damage to dentition. 3. An understanding of the multifactorial nature of tooth wear and risk factors of erosion, abrasion, and ab-fraction is important in the patient's diagnostic protocol and management strategy.

Predictors of Non-carious Loss of Cervical Tooth Tissues

In this sample of subjects, age, premolars and the presence of corrosive factors were found to be significantly associated with NLCTT. The long-term success of treating such a lesion is dependent on properly identifying and eliminating the etiologic factors.

EDTA Gel Root Conditioning: Lack of Effect on Clinical and Radiographic Outcomes of Intrabony Defect Treatment With Enamel Matrix Derivative

BACKGROUND

The adjunctive use of enamel matrix derivative (EMD) in the surgical therapy of intrabony defects results in improved outcomes compared to surgical debridement alone. However, the role of EDTA root conditioning in EMD therapy has not been investigated. The purpose of this study was to compare the 12-month outcomes of EMD application with and without EDTA root conditioning in intrabony defect surgical therapy.

METHODS

Twenty-eight chronic periodontitis patients, each contributing a 2- or 3-wall intrabony defect (> or = 4 mm deep and > or = 2 mm wide), participated. Patients consecutively received surgical treatment with either EMD alone (first 13 patients) or EMD + EDTA (subsequent 15 patients). Probing depth (PD), clinical attachment level (CAL), and gingival margin position, i.e., recession (REC) were the clinical parameters recorded. Recorded radiographic parameters were the distances from 1) cemento-enamel junction to bone crest (CEJ to BC), 2) CEJ to base of the defect (CEJ to BD), and 3) BC to BD.

RESULTS

Intragroup analysis showed that both EMD alone and EMD + EDTA led to significant PD reduction, CAL gain, and REC increase 1 year postoperatively. Both groups had >60% mean radiographic defect resolution (change in BC to BD). None of the recorded parameters were significantly different between the two groups, either at baseline or postoperatively.

CONCLUSIONS

These results suggest that clinical and radiographic outcomes of intrabony defect EMD therapy do not depend on the use of EDTA gel root conditioning. The potential contribution of EDTA gel root conditioning to the histological outcomes reported with EMD therapy remains to be determined.

[External root resorption]

Root resorption may be a physiological (resorption of deciduous teeth) or a pathological process (resorption of permanent teeth). In the latter case an external and an internal form of resorption can be distinguished. Root resorption may occur on one tooth or on several teeth within a dentition and it may be caused by trauma, periodontitis, orthodontic treatment, internal bleaching, cysts, tumors, or by stimuli from a necrotic dental pulp. Current knowledge concerning the pathogenesis of root resorption and therapeutic approaches are presented. For cervical resorption, it is assumed that the stimulus for the resorbing cells originates from the bacteria within the gingival sulcus and along the affected root surface. The case presented here was initially diagnosed as chronic periodontitis of medium severity. Scaling and root planing were performed resulting in a significant improvement of the periodontal status. Two years later, following a period of irregular recall visits, the patient presented with large areas of cervical resorption on teeth 36 and 37 which made it impossible to preserve these teeth. After another six months, teeth 34 and 35 showed deep destruction caused by external root resorption, mandating the extraction of these teeth as well. Fourteen months later, external root resorptions were evident on teeth 32 and 33, and at the same time, a recurrence of the chronic periodontitis was noted. Periodontal therapy was performed under a systemic antibiotic regime. It was possible to preserve teeth 32 and 33 through surgical crown lengthening procedures. No additional resorption has been observed ever since.

Multiple teeth showing invasive cervical resorption - an entity with little known histologic features

Invasive cervical resorption is a relatively uncommon form of external root resorption, characterized by resorption of the cervical region of the root. There is progressive loss of cementum and dentine with replacement by fibrovascular tissue derived from the periodontal ligament, with deposition of cementum-like hard tissue. In most cases, a single tooth is involved. We report a case of invasive cervical resorption that resulted in loss of multiple teeth from two different quadrants. The case highlights the diagnostic difficulty that may arise in this uncommon lesion, the pathologic features of which may be mistaken for a fibro-osseous lesion or a low-grade sarcoma.

A Histopathologic Investigation on the Effects of Electrical Stimulation on Periodontal Tissue Regeneration in Experimental Bony Defects in Dogs

BACKGROUND

One endpoint of periodontal therapy is to regenerate the structure lost due to periodontal disease. In the periodontium, gingival epithelium is regenerated by oral epithelium. Underlying connective tissue, periodontal ligament, bone, and cementum are derived from connective tissue. Primitive connective tissue cells may develop into osteoblasts and cementoblasts, which form bone and cementum. Several procedural advances may support these regenerations; however, the regeneration of alveolar bone does not always occur. Therefore, bone stimulating factors are a main topic for periodontal reconstructive research. The present study was designed to examine histopathologically whether the application of an electrical field could demonstrate enhanced alveolar and cementum regeneration and modify tissue factors.

METHODS

Seven beagle dogs were used for this experiment. Mandibular left and right sides served as control and experimental sides, respectively, and 4-walled intrabony defects were created bilaterally between the third and fourth premolars. The experimental side was treated with a capacitively coupled electrical field (CCEF) (sinusoidal wave, 60 kHz, and 5 V peak-to-peak), applied for 14 hours per day. The following measurements were performed on the microphotographs: 1) the distance from the cemento-enamel junction to the apical notch (CEJ-AN) and from the crest of newly formed bone (alveolar ridge) to the apical notch (AR-AN); 2) the thickness of new cementum in the apical notch region; and 3) the length of junctional epithelium. The following histopathologic parameters were assessed by a semiquantitative subjective method: 1) inflammatory cell infiltration (ICI); 2) cellular activity of the periodontal ligament; 3) number and morphology of osteoclasts; 4) resorption lacunae; and 5) osteoblastic activity.

RESULTS

The results showed that the quantity of new bone fill and the mean value of the thickness of the cementum were significantly higher for the experimental side (P < 0.01). The location of the base of the pocket was positioned more coronally with respect to the apical point of the coronal notch in the experimental side (statistically significant P < 0.01). The length of the junctional epithelium and the number of osteoclasts were higher in the stimulated side than the coronal side; these findings were also statistically significant (P < 0.01). The comparison of the electrically stimulated versus non-stimulated mandibles with the semiquantitative subjective method demonstrated statistically significant differences in defined histopathologic parameters, except for osteoclast morphologies (P > 0.05).

CONCLUSIONS

This study demonstrated that the CCEF method has the potential to produce reconstructive effects and bone deposits. Further investigations with respect to the theoretical determination of local field parameters of the periodontal tissue complex, such as permittivity, conductivity, strength of the field electrical stimulation applied to the periodontal field current density, wavelength, and signal frequency appropriate for this field, should be undertaken. Using different electromotive forces alone or in combination with bone graft materials, guided tissue regeneration techniques, and dental implants may achieve a new dimension in periodontal therapy in the near future.

[Prevalence and etiologic factors of non-carious cervical lesions. A study in a Senegalese population]

The non carious cervical lesion (NCCL) is a loss of tooth tissue at the neck of affected teeth that is unrelated to tooth decay. They are commonly encountered in clinical practice and present in a variety of forms. The purpose of this paper is to determine the prevalence of the NCCL in a Senegalese population. From 655 patients, 112 with cervical lesions were identified i.e. a global prevalence of 17.10%. The prevalence rate for abrasion was reported to be 77.70%, 12.50% for abfraction and 9.80% for erosion. Etiological factors were studied for abrasion and erosion. 54% of the patients with abrasion used their toothbrush horizontally. For erosion, only external factors were identified: consumption of acidic drinks (9 patients) or alcohol (1 patient) and professional environment (1 patient). Dentists should consider these lesions in their daily practice.

Celebrex offers a small protection from root resorption associated with orthodontic movement

Tooth movement results from alveolar bone resorption/deposition following application of orthodontic forces, and root resorption can be an undesirable complication associated with this process. No treatment for external root resorption is available to date.

OBJECTIVE

To determine if COX-2 inhibitors like Celebrex are effective in protecting root resorption associated with orthodontic forces.

METHODS

A force of 80 grams was applied to the left maxillary first molars of 7-week-old female Wistar rats using nickel titanium closed coil springs attached to the cervical area of the incisors with 0.010 stainless-steel ligature wires. Twenty animals were divided into three experimental groups: one receiving no treatment, the second receiving 25mg/kg, and the third receiving 50 mg/kg of celecoxib (Celebrex) in their drinking water. Rats were maintained on a soft diet and euthanized two weeks after initial placement of the force. Paraffin-embedded sections of the right (control) and left (experimental) maxillae were stained with H&E and the areas of root resorption were examined by counting the number of lacunaes in the roots.

RESULTS

No difference in the distance of tooth movement (0.5 mm/two weeks) was seen in all three groups. The rats that received the low dose of Celebrex showed no statistically significant difference in root resorption than that of the rats that received no dose. The rats that received the high dose of Celebrex showed a lower number of lacunaes (mean = 3.5) than that of the control group (mean 10.2; p=0.02).

CONCLUSIONS

Administration of Celebrex during the application of orthodontic forces does not interfere with tooth movement and appears to offer some slight protection against root resorption.

The two-year clinical performance of esthetic restorative materials in noncarious cervical lesions

BACKGROUND

Materials used in restoration of cervical lesions include resin-modified glass ionomer cements, polyacid-modified resin-based composites and resin-based composites. In this study, the authors evaluated the clinical performance of these materials over a two-year period.

METHODS

Thirty patients were enrolled in this study. The authors placed in these patients 130 restorations, 24 of which were Vitremer (3M Dental Products, St. Paul, Minn.), 38 were F2000 Compomer (3M Dental Products), 46 were Dyract AP (Dentsply DeTrey, Konstanz, Germany) and 22 were Valux Plus (3M Dental Products). Enamel margins were not beveled, and no mechanical retention was placed. Two independent, calibrated examiners evaluated the restorations baseline and at one and two years after placement using modified U.S. Public Health Service criteria.

RESULTS

Retention rates at the end of two years were 100 percent for Vitremer, 67 percent for F2000 Compomer, 68 percent for Dyract AP and 70 percent for Valux Plus. The retention rate of Vitremer was significantly higher than that of the others (P < .05). In other categories, however, Valux Plus had the most favorable performance (P < .05). No secondary caries was detected around any restoration.

CONCLUSION

Vitremer, with its high retention rate, seems to be the most appropriate material for restoration of noncarious cervical lesions, though it does not have the esthetic properties of resin-based composites. All materials used in this study were in need of improvements.

CLINICAL IMPLICATIONS

Resin-modified glass ionomer cement, polyacid-modified resin-based composite and resin-based composite behaved differently in the restoration of noncarious cervical lesions. Therefore, clinicians should take factors such as esthetic needs and localization into account in selecting materials for such restorations.