- Email: [email protected]
Erbium:YAG laser for retrograde cavity preparation
Implants Intrusion and periodontal support in complete-arch FPDs Background.—Few studies have focused on the outcome of implant- and tooth-supported prostheses in complete-arch designs when the patient has either normal or reduced periodontal support. The clinical outcomes achieved with the use of a complete-arch fixed partial denture (FPD) supported by tooth and implant abutments in these patients were evaluated. Methods.—Nineteen patients had combined toothand implant-supported complete-arch FPDs placed. All had residual teeth. Their outcomes were evaluated 24 to 94 months after the prostheses were placed. In 9 patients, the periodontal support was reduced because of periodontal disease and treatment; in 10 patients, the periodontal support was normal. The components of the FPDs included 90 implants and 72 tooth abutments. In all cases, the implant survival and success rates, occurrence of caries and tooth intrusion, and prosthetic complications were documented. Results.—The implant survival rate was 99%, but 3 implants lost more than 2 mm of crestal bone, for a success rate of 96%. No caries developed, but intrusion was found in 5.6% of the abutment teeth. Thirteen percent of the normal periodontal support group had intrusion that was associated with nonrigid connectors. None of the reduced periodontal group demonstrated intrusion, regardless of the type of connector used. None of the teeth in either group showed intrusion when rigid connectors were used. Patients with intact periodontal support had a significantly higher number of intruded teeth.
Discussion.—The survival rate for the implants was 99%, with a success rate of 96%. None of the patients developed caries during the follow-up period. Only patients with normal periodontal support suffered prosthetic complications. Specifically, patients with intact periodontal support developed intrusion of the abutment teeth associated with nonrigid connectors. No cases of intrusion developed when the patient had reduced periodontal support regardless of the connector type used.
Clinical Significance.—Connection of osseointegrated implant and natural tooth abutments in fixed prostheses has been taboo, the mysterious intrusion of the natural tooth the feared result. While intrusion was noted in some teeth with intact periodontal support and nonrigid connectors, none occurred in teeth with reduced support, regardless of connector type used. Why intrusion occurs remains a mystery and telescope crowns should be considered.
Cordaro L, Ercoli C, Rossini C, et al: Retrospective evaluation of complete-arch fixed partial dentures connecting teeth and implant abutments in patients with normal and reduced periodontal support. J Prosthet Dent 94:313-320, 2005 Reprints available from L Cordaro, Via Guido d’ Arezzo 2, 00198 Rome, Italy; fax: 39-06-8553162; e-mail: [email protected]
Lasers Erbium:YAG laser for retrograde cavity preparation Background.—Apicoectomy is done to remove irritants from the root canal system, which could cause periapical inflammation. A retrograde filling is normally required. Ideally, the root-end cavity preparation is a Class I cavity at least 3 mm deep with parallel walls, but this is difficult to achieve because of limited access, root anatomy, and tooth angulation. The piezoelectric ultrasonic devices developed for root-end preparation produce a high inci-
234 Dental Abstracts
dence of cracks in the dentin wall during preparation. Erbium:YAG (Er:YAG) laser use for apicoectomy has been proposed, citing the lack of vibration, lessened chance of contaminating the operating field, and reduced risk of trauma to the surrounding tissues compared with the ultrasonic devices. Lack of tactile feedback and slowness of ablation for hard dental tissues have been raised as drawbacks to the laser’s use. Variable Square Pulse technology provides
electronic control of the laser pulse duration and amplitude, permitting pulses of very short duration that increase the ablation rate of hard dental tissues and reduce the heat generated. A comparison of irradiation with use of the Er:YAG laser equipped with Variable Square Pulse technology and irradiation with use of an ultrasonic technique was carried out, noting their sealing ability for various filling materials placed in retrograde cavities.
Discussion.—The Er:YAG laser technique was effective in retrograde cavity preparation compared with the standard ultrasound technique. Mineral trioxide aggregate had the best sealing ability of the samples, reaching statistically significant results for laser-prepared cavities. The use of extracted teeth for the study facilitated root-end preparation, so in vivo testing is still required.
Methods.—Root-canal instrumentation and filling were carried out on 60 single-rooted teeth. Their apices were then resected and retrograde Class I cavities 3 mm deep prepared with use of either the ultrasound device or the Er:YAG laser. The pulse for the laser was of very short duration (100 µs), energy was 280 mJ, and repetition rate was 10 Hz. The filling materials were mineral trioxide aggregate, Super-EBA, and IRM.
Clinical Significance.—Apical seal remains the essence of endodontic success. In this in vitro study, root-end preparations performed with laser consistently showed less leakage than those made with ultrasonics, regardless of the sealing material used. How to apply this technique in vivo needs further study.
Results.—Significant differences were noted between the samples prepared by the ultrasonic and laser techniques. Regardless of which sealer was used, samples prepared with the laser technique demonstrated less microleakage than those prepared with the ultrasonic technique. The samples sealed with mineral trioxide aggregate differed significantly from those sealed with IRM and Super EBA for the laser-prepared samples, but not for the ultrasound-prepared samples.
Karlovic Z, Pezelj-Ribaric S, Miletic I, et al: Erbium:YAG laser versus ultrasonic in preparation of root-end cavities. J Endodont 31:821823, 2005 Reprints available from I Miletic, Dept of Endodontics and Restorative Dentistry, School of Dental Medicine, Gunduli´ceva 5, 10,000 Zagreb, Croatia; e-mail: [email protected]
Nutrition Dental effects of fruit juices Background.—Fruit juices are perceived worldwide as a healthy alternative to carbonated beverages, providing particularly a good source of vitamin C. However, fruit juices have erosive effects on tooth enamel because of their acidic nature. The excessive consumption of fruit juices poses a hazard, especially for young children whose primary dentition lacks the structure of permanent teeth. To document the negative effects of fruit juice, plaque and salivary pH values were obtained after children consumed various fruit juices at different temperatures. Methods.—Thirty children ages 10 to 12 years underwent thorough oral prophylaxis, then refrained from
brushing their teeth or using oral hygiene aids for 24 hours. They did not eat food or drink for at least 8 hours before beginning the study activities. Three groups of 10 subjects each were exposed to freshly prepared pineapple, orange, and grape juices at room, refrigeration, and freezing temperatures for the next 3 days. Their salivary and plaque pH values were measured and compared. Results.—Grape juice had the lowest pH, followed by orange and pineapple juice. Frozen fruit juices had the lowest pH, with refrigerated juices next and finally room temperature juices. The reduction in plaque and salivary pH was maximal within 5 minutes of consuming the juice.
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Discussion.—The survival rate for the implants was 99%, with a success rate of 96%. None of the patients developed caries during the follow-up period. Only patients with normal periodontal support suffered prosthetic complications. Specifically, patients with intact periodontal support developed intrusion of the abutment teeth associated with nonrigid connectors. No cases of intrusion developed when the patient had reduced periodontal support regardless of the connector type used.
Clinical Significance.—Connection of osseointegrated implant and natural tooth abutments in fixed prostheses has been taboo, the mysterious intrusion of the natural tooth the feared result. While intrusion was noted in some teeth with intact periodontal support and nonrigid connectors, none occurred in teeth with reduced support, regardless of connector type used. Why intrusion occurs remains a mystery and telescope crowns should be considered.
Cordaro L, Ercoli C, Rossini C, et al: Retrospective evaluation of complete-arch fixed partial dentures connecting teeth and implant abutments in patients with normal and reduced periodontal support. J Prosthet Dent 94:313-320, 2005 Reprints available from L Cordaro, Via Guido d’ Arezzo 2, 00198 Rome, Italy; fax: 39-06-8553162; e-mail: [email protected]
Lasers Erbium:YAG laser for retrograde cavity preparation Background.—Apicoectomy is done to remove irritants from the root canal system, which could cause periapical inflammation. A retrograde filling is normally required. Ideally, the root-end cavity preparation is a Class I cavity at least 3 mm deep with parallel walls, but this is difficult to achieve because of limited access, root anatomy, and tooth angulation. The piezoelectric ultrasonic devices developed for root-end preparation produce a high inci-
234 Dental Abstracts
dence of cracks in the dentin wall during preparation. Erbium:YAG (Er:YAG) laser use for apicoectomy has been proposed, citing the lack of vibration, lessened chance of contaminating the operating field, and reduced risk of trauma to the surrounding tissues compared with the ultrasonic devices. Lack of tactile feedback and slowness of ablation for hard dental tissues have been raised as drawbacks to the laser’s use. Variable Square Pulse technology provides
electronic control of the laser pulse duration and amplitude, permitting pulses of very short duration that increase the ablation rate of hard dental tissues and reduce the heat generated. A comparison of irradiation with use of the Er:YAG laser equipped with Variable Square Pulse technology and irradiation with use of an ultrasonic technique was carried out, noting their sealing ability for various filling materials placed in retrograde cavities.
Discussion.—The Er:YAG laser technique was effective in retrograde cavity preparation compared with the standard ultrasound technique. Mineral trioxide aggregate had the best sealing ability of the samples, reaching statistically significant results for laser-prepared cavities. The use of extracted teeth for the study facilitated root-end preparation, so in vivo testing is still required.
Methods.—Root-canal instrumentation and filling were carried out on 60 single-rooted teeth. Their apices were then resected and retrograde Class I cavities 3 mm deep prepared with use of either the ultrasound device or the Er:YAG laser. The pulse for the laser was of very short duration (100 µs), energy was 280 mJ, and repetition rate was 10 Hz. The filling materials were mineral trioxide aggregate, Super-EBA, and IRM.
Clinical Significance.—Apical seal remains the essence of endodontic success. In this in vitro study, root-end preparations performed with laser consistently showed less leakage than those made with ultrasonics, regardless of the sealing material used. How to apply this technique in vivo needs further study.
Results.—Significant differences were noted between the samples prepared by the ultrasonic and laser techniques. Regardless of which sealer was used, samples prepared with the laser technique demonstrated less microleakage than those prepared with the ultrasonic technique. The samples sealed with mineral trioxide aggregate differed significantly from those sealed with IRM and Super EBA for the laser-prepared samples, but not for the ultrasound-prepared samples.
Karlovic Z, Pezelj-Ribaric S, Miletic I, et al: Erbium:YAG laser versus ultrasonic in preparation of root-end cavities. J Endodont 31:821823, 2005 Reprints available from I Miletic, Dept of Endodontics and Restorative Dentistry, School of Dental Medicine, Gunduli´ceva 5, 10,000 Zagreb, Croatia; e-mail: [email protected]
Nutrition Dental effects of fruit juices Background.—Fruit juices are perceived worldwide as a healthy alternative to carbonated beverages, providing particularly a good source of vitamin C. However, fruit juices have erosive effects on tooth enamel because of their acidic nature. The excessive consumption of fruit juices poses a hazard, especially for young children whose primary dentition lacks the structure of permanent teeth. To document the negative effects of fruit juice, plaque and salivary pH values were obtained after children consumed various fruit juices at different temperatures. Methods.—Thirty children ages 10 to 12 years underwent thorough oral prophylaxis, then refrained from
brushing their teeth or using oral hygiene aids for 24 hours. They did not eat food or drink for at least 8 hours before beginning the study activities. Three groups of 10 subjects each were exposed to freshly prepared pineapple, orange, and grape juices at room, refrigeration, and freezing temperatures for the next 3 days. Their salivary and plaque pH values were measured and compared. Results.—Grape juice had the lowest pH, followed by orange and pineapple juice. Frozen fruit juices had the lowest pH, with refrigerated juices next and finally room temperature juices. The reduction in plaque and salivary pH was maximal within 5 minutes of consuming the juice.
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