Quintessence International, 03/2009

Dentin dysplasia is a genetic defect of dentin formation inherited as an autosomal dominant trait. It is characterized by normal enamel but atypical dentin formation with abnormal pulpal morphology. Once thought to be a single entity, dentin dysplasia has now been divided into type I (radicular) and II (coronal). Type I is by far the more common. Both types include multiple/generalized involvement of primary and permanent dentition. Combinations of both types have also been described in the literature. Four distinct forms of dentin dysplasia type I and 1 form of dentin dysplasia type II are identified. Although there seems to be no need to identify more than 2 distinct types of this relatively rare inherited defect of human dentin, the possible existence of additional forms of the disease cannot be ruled out. Here is a case report of dentin dysplasia in a single tooth, with crown and roots of normal dimensions, associated with severe pain and mobility and histologically involving both coronal and radicular dentin. Focal odontoblastic dysplasia or dentin dysplasia type III could be the new entity. Keywords: dentin dysplasia, odontoblastic dysplasia

This case report is of maxillary central incisors still in place 38 years after periodontal surgery to correct the damage to supporting tooth structure caused by an orthodontic elastic band. Keywords: attachment loss, orthodontic elastic band, periodontal surgery

In implant patients who have extended soft tissue deficiencies, split skin grafts have been performed for the prevention of peri-implant inflammation. The aim of this investigation was to assess a patient who received 2 interforaminal implants and a split skin graft 13 years prior. In addition to clinical, mycologic, and radiographic examinations, the condition of the split skin graft was evaluated using histologic analysis of 3 punch biopsies taken from the mucosa, grafted area, and border between both areas. The implants were found to have an overall good clinical condition. Fungal infection was not present. The histologic analysis revealed inflammation-free mucosal and submucosal tissue in all samples. In the area of the skin graft, the mucosa was not keratinized and showed an increased thickness of the submucosal connective tissue. For the patient under examination, an acceptable level of oral rehabilitation was achieved using a split skin graft. The follow-up investigation showed stable conditions for both the implants and the graft. Keywords: implant therapy, interforaminal implants, long-term results, split skin graft, telescopic crowns

Objective: To evaluate the influence of reservoirs on the gingival mucosa of patients submitted to at-home bleaching with 16% carbamide peroxide. Method and Materials: Nineteen nonsmoking male patients, 18 to 25 years of age, were submitted to home bleaching with a 16% carbamide peroxide gel for 2 consecutive hours for 21 days. The custom-made mouth trays were made with a reservoir on only the left side and cut anatomically 1 mm beyond the gingival margin. Smears of the gingival mucosa were obtained by the exfoliation cytology in liquid media technique before (control), immediately after, and 30 and 45 days after treatment. The samples were processed in the laboratory and evaluated according to Papanicolaou's criteria of malignity. Statistical analysis was carried out by McNemar test, 2 proportions test, and Wilcoxon test with a level of significance of 1%. Results: The presence of a reservoir in the custom tray resulted in an increase of inflammation only immediately after the bleaching procedure. After 30 and 45 days, the difference between inflammation on the sides with and without a reservoir was not statistically significant. Significant differences were found in the degree of inflammation, classified as predominantly mild on the nonreservoir side and moderate on the reservoir side (P .01). Conclusions: A 16% carbamide peroxide bleaching gel caused gingival inflammation immediately after the procedure and persisted until 45 days after the bleaching treatment. The use of a reservoir in the custom tray for home bleaching resulted in higher rates and higher intensity of gingival inflammation. Keywords: carbamide peroxide, dental bleaching, exfoliative cytology, gingival inflammation, reservoir, tray

Objectives: Curing light sources propel the photopolymerization process. The effect of 3 curing units on polymerization shrinkage and depth of cure was investigated. Method and Materials: The curing lights were a conventional and a soft-start quartz-tungstenhalogen (QTH) light source and a light-emitting diode (LED) source. The soft-start QTH and LED intensity outputs were 9% and 17% less than the conventional QTH source, respectively. For a 40-second light cure, the light energy was 32% and 14% lower, respectively. The light sources were applied to 4 restorative composites (microfilled, 2 hybrids, and nanofilled). For each light unit-composite combination, the development of postgel shrinkage during polymerization was measured with strain gauges (n = 15), and the Knoop hardness was tested at 0.5-mm-depth increments to assess degree of cure 15 minutes after polymerization (n = 5). The results were statistically analyzed with 2-way ANOVA at .05 significance level, followed by pairwise comparisons. Results: Both factors, light source and composite, significantly affected postgel shrinkage and hardness (P .05). The conventional QTH unit generally produced the highest shrinkage and hardness (at composite surface and 2-mm depth). The soft-start QTH unit generated the least shrinkage but achieved the lowest depth of cure. The resulting values for the LED unit were mostly in between the results of the other 2 units. Conclusion: Curing lights should provide sufficient light energy to thoroughly cure composite restorations, which might be achieved without compromising shrinkage stresses if initial intensity is reduced. Keywords: composite, cure, curing light, hardness, light energy, light intensity, shrinkage, soft start

Objective: To investigate the bacteriostatic and cariostatic effect of a novel povidone-iodine/fluoride foam in children at high risk for caries. Method and Materials: Sixty-one 6- to 9-year-old children with at least 1 active dental caries lesion were randomly assigned to 2 groups and treated weekly with either povidone-iodine/fluoride foam (n = 30, experimental group) or placebo fluoride foam (n = 31, control group) for 4 weeks. Stimulated saliva samples were collected for bacteriostatic assessment before each treatment and at 2 and 6 months during the experiment. In addition, laser fluorescence readings of the permanent first molars were taken for the evaluation of cariostatic effect before the treatment and at 2, 6, and 12 months during the experiment. Results: Both groups showed a constant decrease of salivary mutans streptococci over 6 months. Significantly lower laser fluorescence readings were observed for both groups at the 6th month, although with a slight reverse at the 12th month. However, no statistically significant difference was achieved between the 2 groups either for salivary bacteria levels over 6 months or laser fluorescence readings within 1 year. Conclusion: As far as bacteriostatic and cariostatic effects are concerned, clinical application of povidone-iodine/fluoride foam shows no superiority over the regular fluoride foam during a 1-year period. Evidence is still lacking for the combination use of povidone-iodine and fluoride to achieve a better caries-prevention effect in a highcaries- risk population. Keywords: bacteriostatic effect, cariostatic effect, caries prevention, DIAGNOdent, fluoride, povidone-iodine

Objective: The use of self-etch adhesives has increased in spite of reports of deficient enamel bonding. Some clinicians etch enamel separately to circumvent this shortfall. Therefore, the objective of this study was to assess the influence of acid-etching on the enamel sealing of 3 self-etch adhesives after thermal fatigue. Method and Materials: Two box-type preparations were restored in each of 30 bovine incisors with 1 of 3 selfetch adhesives: Adper Prompt L-Pop (3M ESPE); Clearfil SE Bond (Kuraray America); or iBond (Heraeus Kulzer), with and without phosphoric acid enamel etching, followed by Filtek Z250 (3M ESPE). After half of the restorations were fatigued for 1,500 thermal cycles, marginal sealing was challenged with 50% ammoniacal silver nitrate. Silver penetration was ranked from 0 to 4 and interfaces analyzed under a field-emission scanning electron microscope (FESEM) with a backscattered detector. Nonparametric statistical analyses were carried out at a 95% confidence level. Results: Clearfil SE Bond resulted in significantly less enamel leakage than the other 2 self-etch adhesives. Acid etching significantly reduced silver infiltration for all adhesives when specimens were thermocycled. When specimens were not thermocycled, acid etching only reduced silver infiltration for iBond. Under the FESEM, silver deposition was observed inside the adhesive layer for Adper Prompt L-Pop and iBond. For Clearfil SE Bond only 2 of 10 specimens displayed silver infiltration along the enamel-adhesive interface. Conclusion: Etching with phosphoric acid improved the enamel marginal sealing of the 3 self-etch adhesives when specimens were subjected to thermal fatigue. Keywords: dental leakage, enamel etching, scanning electron microscopy, self-etch adhesives

Objective: Oral lichen planus (OLP) is a common mucocutaneous disease with malignant transformation potential. The aim of this retrospective study was to investigate the characteristics of patients with OLP who developed oral squamous cell carcinoma (OSCC). Method and Materials: The medical records of 2,119 patients with OLP at West China College of Stomatology, China, from 1951 to 2006, were reviewed. Data were taken from the records of 23 patients with OLP who developed OSCC. Results: The rate of malignant transformation in OLP was 1.1%. The mean age of these patients was 52 years. There were 12 women and 11 men. There was no significant difference between women and men (P = .835). The most common site of malignant transformation was in the tongue (16; 69.57%). The average time from the patient's first visit with OLP to malignant transformation was 16 months (range, 1 to 41 months). More than 50% of patients had alcohol (12; 52.17%) and tobacco (13; 56.52%) habits. Before the malignant transformation, the most frequent symptoms in patients with OLP were pain (21; 91.30%) and erosion (17; 73.91%). Conclusions: The risk of malignant transformation in OLP is real but not high. Erosive OLP in older patients with pain and who use tobacco and alcohol is more likely to exhibit malignant transformation. Keywords: malignant transformation, oral lichen planus, oral squamous cell carcinoma

Objective: To evaluate the effect of different preparation angles on the marginal and internal fit of zirconia single-crown copings. Method and Materials: Three ivorine maxillary right first molars were prepared with preparation angles of 4, 8, and 12 degrees. Impressions were made of each abutment tooth to obtain 20 specimens per group. The copings were manufactured by a CAD/CAM system and milled from semi-sintered zirconia blanks. After sintering, 10 copings were randomly chosen from each group and adapted by a dental technician. All 60 copings were cemented with glass ionomer on the master casts. After embedding, all specimens were cross-sectioned. Both marginal and internal fit were evaluated under an optical microscope. A 1-way analysis of variance (ANOVA) and a nonparametric test (Mann-Whitney U) were used to compare data (α = .05). Results: The 4-degree copings showed a mean marginal gap of 91 µm (± 15) before and 67 µm (± 8) after adaptation; the 8-degree group exhibited a mean marginal gap of 82 µm (± 13) before and 67 µm (± 11) after adaptation; the 12-degree specimens showed 50 µm (± 6) before and 46 µm (± 6) after adaptation. Adaptation led to a significant improvement of specimens from the 4-degree and 8-degree groups, while no statistical difference could be observed among 12-degree specimens before and after adaptation. Conclusion: The highest marginal gaps were found in the 4- and 8-degree groups. In the group with 12-degree preparation angle, additional adaptation did not improve the fit and can be considered unnecessary under the conditions of this study. Keywords: CAD/CAM technology, crown, internal fit, marginal fit, preparation angle, zirconia

Spinal, general, and epidural anesthesia have been implicated in the exacerbation of multiple sclerosis. However, to date, no attack has been reported following usage of mandibular block articaine anesthesia. This article describes the case of a 30-year-old man who presented with a sudden occurrence of diplopia on lateral gaze the day after extraction of the mandibular right second and third molars. Two times 1.8 mL 4% articaine solution with 1/100,000 adrenaline was used for local anesthesia. On neurological examination, a restriction on external gaze of his left eye was observed. Immunoglobulin G index was high, and oligoclonal band was present in spinal fluid evaluation. MRI revealed demyelinated plaques on the left side of the midpons, right cerebellar hemisphere, and bilateral white matter and supraventricular spaces. The left abducens palsy completely improved after treatment with intravenous methylprednisolone. Mandibular block articaine anesthesia may precipitate multiple sclerosis onset or attack. This case indicates that dental clinicians and neurologists may be alerted to isolated abducens palsy as a possible adverse effect of mandibular block articaine anesthesia. Keywords: anesthesia, articaine, isolated abducens nerve palsy, multiple sclerosis