Re: Class 2 Cavity Preparation Pdf Download
Jahed Stetter
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Following the development of the ruby laser by Maiman in 1960, the Nd:YAG laser, the CO2 laser, the semiconductor laser, the He-Ne laser, excimer lasers, the argon laser, and finally the Er:YAG laser capable of cutting hard tissue easily were developed and have come to be applied clinically. In the present study, the Er:YAG laser emitting at a wavelength of 2.94 microns developed by Luxar was used for the clinical preparation of class V cavities. Parameters of 8 Hz and approx. 250 mJ/pulse maximum output were used for irradiation. Sixty teeth of 40 patients were used in this clinical study. The Er:YAG laser used in this study was found to be a system suitable for clinical application. No adverse reaction was observed in any of the cases. Class V cavity preparation was performed without inducing any pain in 48/60 cases (80%). All of the 12 cases that complained of mild or severe intraoperative pain had previously complained of cervical dentin hypersensibility during the preoperative examination. Cavity preparation was completed with this laser system in 58/60 cases (91.7%). No treatment-related clinical problems were observed during the follow-up period of approx. 30 days after cavity preparation and resin filling. Cavity preparation took between approx. 10 sec and 3 min and was related more or less to cavity size and depth. Overall clinical evaluation showed no safety problem with very good rating in 49 cases (81.7%).
This study determined the feasibility of saucer-shaped cavity preparations for composite resins in class II lesions. Saucer-shaped class II cavity preparations were restored with composite resin and subjected to clinical, radiographic, and replica cast evaluation (39 restorations) after 6, 18, and 36 months. The results indicated that the retention, resistance form, and wear resistance of the class II saucer-shaped cavity preparations were satisfactory after 3 years.
When you have been diagnosed with a cavity, your dentist will need to create an opening in your tooth to remove the decayed substance and restore your tooth with a filling. This is called a cavity preparation. You may also need a preparation when your tooth has a fracture, abrasion or erosion on the tooth surface.
Your dentist will examine your teeth and take x-rays to determine the subtle design features necessary to ensure longevity of your filling. These design features include the shape and size of the opening into your tooth, enabling the dentist to remove the decayed substance, as well as design features to prevent the filling from moving or fracturing. There may be times when the dentist will need to remove a bit of healthy tooth structure in order to gain access to the decayed material.
Cavities can be broken up into six different groups, or classes, depending on which tooth surface, or surfaces, are affected. This is a general illustration of the six classes, but depending on the level of decay, each class may involve more surfaces, or even a combination of classes.
For each of these cavity preparations, the dentist will first clean and numb the affected area. The dentist will use several different instruments to first create the opening, and then remove the decayed material. Once complete, the cavity must be rinsed and cleaned of any remaining debris in preparation for the filling.
The cavity will either be filled with amalgam, which is a silver filling, or resin composite, where the filling is similar to the colour of the tooth. The decision as to which material to use is based on the tooth location and affected surface, as well as patient preference when aesthetics are of concern.
The aim of the present clinically controlled two-year study was to investigate the influence of laser-based cavity preparation on the long-term performance of Class V resin-composite fillings. Class V non-carious lesions (n = 75) were randomly assigned to two test and one control group. Cavities in both test groups were prepared using an Er,Cr:YSGG laser (Waterlase MD, Biolase, Irvine, California, USA). The device was operated at 3 W (150 mJ, 30 J/cm2), 50% water, 60% air, 30 Hz in H mode. Subsequently, laser-prepared tooth surfaces in test group I (n = 21) were additionally conditioned by acid etching (etch-and-rinse). Laser-prepared cavities of test group II (n = 21) received no additional acid conditioning. After application of an adhesive, all cavities were restored using the resin-composite Venus. For cavities in the control group (n = 33) conventional diamond burs were used for preparation which was followed by an etch-and-rinse step, too. The fillings were evaluated immediately (baseline) and after 6, 12 and 24 months of wear according to the C-criteria of the USPHS-compatible CPM-index. The results showed that after 24 month of wear, laser-preparation was associated with fillings of high clinical acceptability. Compared to conventional bur-based treatment, laser-based cavity preparation resulted in fillings with high marginal integrity and superior marginal ledge configurations (p = 0.003). Furthermore, laser-preparation combined with additional acid-conditioning (test group I) resulted in fillings with the best marginal integrity and the lowest number in marginal discoloration, especially at the enamel-composite margins (p = 0.044). In addition, total loss of fillings was also less frequently observed in both laser groups as compared to the control. The results clearly demonstrate that laser-based cavity preparation will benefit the clinical long-time performance of Class V resin-composite fillings. Furthermore, additional acid-conditioning after laser preparation is of advantage.
Copyright: 2022 Heyder et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
As already proven by Galafassi et al. in a 12-month clinical trial, laser-based cavity preparation has a positive effect upon the performance of Class I composite restorations [30]. Furthermore, Er:YAG laser-prepared Class V fillings revealed a more sufficient marginal seal on occlusal and gingival margins as compared to conventional bur-cut restorations In-vitro [31].
Therefore, the present clinical trial aimed at investigating the performance of Class V fillings with cavities prepared using an Er,Cr:YSGG solid-state laser in non-carious cervical lesions. The results were compared to the outcome of Class V fillings placed in traditional bur-cut cavities. Since laser-treated tooth surfaces are of rough appearance the need of an additional acid conditioning is still controversially discussed [32, 33]. In this regard, the present study also observed the effect of an additional etch-and-rinse approach on the clinical long-term success of laser-prepared Class V composite restorations, too.
The present study involved a total of 29 patients recruited from the Department of Conservative Dentistry and Periodontology, Jena University Hospital, Germany. Each patient showed at least one non-carious defect in the cervical region with exposed dentin (Fig 1A). Defects in molars were not included in the study. All participants had to be at least 18 years of age. The age distribution ranged in between 22 and 89 years with a mean age of 56.24 years. The study has been approved by the Ethical Committee of the Friedrich Schiller University, Jena, Germany (No. 2013-05/07) and written informed consent of each patient was given prior to any therapy.
Teeth with cervical lesions due to caries and teeth intended for denture prosthetics in the nearby future were excluded from the study. Other reasons for exclusion were (i) insufficient oral hygiene (approximal plaque index and bleeding on probing > 30%), (ii) excessive smoking (> 20 cigarettes per day), and/or (iii) the consumption of > 5 cups of coffee or black tea per day.
In the control group, conventional bure-based preparation was carried out, following the rules of retentive preparation with bevelled enamel edges. For this purpose, a cylindrical 107 μm diamond bur was used (Komet, Gebr. Brasseler GmbH & Co. KG, Lemgo, Germany) in a contra-angle handpiece 1:5 under constant water cooling (KaVo Dental, Biberach/Ri, Germany). In the marginal region adjacent to the enamel an additional bevel of at least 1 mm of width was prepared, using a flame-shaped 46 μm fine-grain diamond bur (Komet, Gebr. Brasseler GmbH & Co. KG, Lemgo, Germany).
Subsequently, all cavities were treated with Gluma Solid Bond P and Gluma Solid Bond S (Heraeus Kulzer GmbH, Hanau, Germany) as advised by the manufacturer followed by light curing for 40 s each (Translux PowerBlue, Heraeus Kulzer GmbH, Hanau, Germany).
Changes to all restorations starting at baseline up to the final inspection were examined by means of the Friedman test. The Kruskal-Wallis test was used for the global statistical comparison of the methods. Significance between and within the groups was tested by applying the Mann-Whitney U-test.
As shown in Table 2, all 75 fillings displayed correct anatomical forms at baseline (Code 0). Throughout the 2-year examination period, partial changes in the filling contour (Code 1) were detected among all groups.
Total loss of fillings (Code 3) occurred most frequently within the control group. In detail, after 6 months of wear 4 restorations were lost completely, followed by another two fillings after 12 months and one after 24 months.
The integrity of the filling margins was examined separately for the enamel and dentin margins (Table 3). At all examination times, fillings in the test groups showed less insufficient margins adjacent to the enamel (Code 1 and 2) as compared to the control. After one year this result turned up to be significant (p = 0.003). Between both test-groups no significant difference was observed (p = 0.513).
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