Schwarz George
Applications of lasers in dentistry: an overview
Applications of lasers in dentistry: an overview
Author:
Prof. (Dr.) Bashir Mir A
Professor,
Dept Oral and Maxillofacial Surgery,
Govt. Dental College, SGR.
Co authors:
Dr Ajaz A Shah
Associate professor and head,
Department of Oral and Maxillofacial Surgery,
Govt. Dental College, SGR.
Dr. Suhail Latoo
Teacher
Department of Oral Pathology and Microbiology,
Govt. Dental College, Sgr
Dr. Altaf Malik H
Dept. Oral and Maxillofacial Surgery,
Govt. Dental College, Sgr
ABSTRACT
Lasers were introduced in the field of clinical dentistry in the hope of overcoming some of the disadvantages resulting from conventional methods of dental procedures. Since its first experiment for dental use in the year 1960, the use of the laser increased rapidly in the last few decades. At present, wide variety of procedures are performed using lasers. The purpose of this review is to describe the application of lasers in dental hard tissue procedures. Lasers prove to be effective in cavity preparation, caries removal, restoration removal, etching, and the treatment of dentin sensitivity, caries prevention and bleaching. Based the developments in adhesive dentistry and the spread principles of minimal intervention, lasers can mean cavity design and preparation.
Keywords: laser dental hard tissue, adhesive dentistry
INTRODUCTION
The use of lasers in dentistry has increased in recent years. The first laser was introduced in the fields of medicine and dentistry during the year 1960 (Goldman et al., 1964). Since then, this knowledge quickly. Because of their many advantages, lasers have been indicated for a wide range of procedures (Frentzen and fever, 1990, Aoki et al, 1994; .. Pelagalli et al, 1997; Walsh, 2003). Conventional methods of cavity preparation with low-and high-speed handpieces involve noise, vibration and stress for patients uncomfortable. Although pain can be reduced by local anesthesia, fear of the needle and of sound and vibrations of mechanical preparation still causes discomfort. These drawbacks have led to a quest for new technologies as potential alternatives to dental hard tissues. The purpose of this review is to describe the application of lasers in dental hard tissue procedures.
Historical development
The first experiments with lasers in dentistry has been reported in a study on the effects of a pulsed ruby laser on human caries (Goldman et al, 1964). The results of that study showed that the effects varied from small 2-mm deep holes in the disappearance of the carious tissue completely, with some whitening of the surrounding edge of enamel, indicating extensive destruction of carious areas together with the crater formation and melting of dentin. Further work in the years 1970 focused on the effects of neodymium (ND) and carbon dioxide (CO2) lasers on dental hard tissues. Early investigation revealed that CO2 lasers produced cracking and disruption of enamel bars, combustion of dentin tubules content, excessive loss of tooth tissue, carbonization and cracking and increased mineralization caused by the removal of organic content (Gimbel, 2000). It was also reported that use of the CO2 laser was unfavorable because of the loss of the odontoblastic layer (Wigdor et al., 1993).
It was therefore concluded that, unless heat-related structural changes and damage to dentin tissues could be reduced, laser technology can not replace the conventional dental drill. Further progress in laser technology, however, have found acceptable biological interactions. For example the Er: YAG laser was tested for its ability (or evaporate) dental hard tissues (Gimbel, 2000) ablation. Enamel and dentin cavities were successfully used the Er: YAG laser. Since then, this laser is used for caries removal and cavity preparation, soft tissue minor surgery and scaling (Aoki and Watanabe et al., 1998).
CLINICAL APPLICATIONS
Cavity
The Er: YAG laser was tested with the preparation of dental hard tissues for the first time in 1988. It was successfully used for holes in enamel and dentin prepared low "influences" (Energy (MJ) / unit area (cm2)). Even without water cooling (Burke et al., 1992), the prepared cavities showed no cracks and little or no carbonization, while the average temperature rise of the pulp cavity was about 4.3 ° C (Rech Mann et al., 1998). In 1989, it was shown that the Er: YAG Laser holes in enamel and dentine without major side effects produced. The ablation efficiency was about one order of magnitude lower than for soft tissue. It was concluded that dentin Remove and glaze was very effective with no risk to the pulp (Armengol, 2000; Cavalcanti, 2003) and ablation rates in enamel were mentioned to be in the range of 20-50 um / Wrist, and in dentin were reported to be higher at lower influences.
Clinically, results in cavity preparation in enamel ablation craters with a white chalky appearance on the surface of the crater (Tokonabe et al, 1999). In dentin, cavity margins are sharp and open dentin tubules remain without a smear layer. In a clinical study to improve efficiency and to assess the safety of the Er: YAG laser for caries removal and cavity preparation in dentin and enamel (Cozean et al, 1997), Class I, II, III, IV and V cavities prepared to amalgam and composite restorations. It appeared that the Er: YAG laser was equivalent to air rotor in its ability to cavity preparations in enamel and dentine caries and remove. However, the floor of the preparation was not as smooth as that of the high-speed drills.
Caries Removal
Carious material contains a higher water content compared to surrounding healthy dental hard tissues. Consequently, the ablation efficiency of caries is greater than in healthy tissues. There is a potential selectivity in the removal of carious material using the Er: YAG laser because of the different energy requirements for sound and carious tissue from healthy tissue that minimally affected ablation. However, Rech Mann et al. (1998) found that selective removal of carious dentine is difficult with the Er: YAG laser. The ablation thresholds of sound dentin and carious dentin are different. The ablation threshold of healthy dentin is twice higher than the threshold of carious dentin.
Therefore, very small effects (energy (Joules) / (cm2)) of Er: YAG laser selective ablation energy to carious dentin. This low fluence will result in a low efficiency of the ablation process (Shigetani, 2002). In another in vitro study the effectiveness of caries removal by Er: YAG laser, showed that the Er: YAG laser ablation carious dentin effectively with minimal thermal damage to the surrounding intact dentine (Aoki and Ishikawa et al., 1998). The laser removed infected and softened carious dentin to the same extent as the drill treatment. In addition, a lower degree of vibration noted with the Er: YAG laser treatment. However, the study did not address the issue of selective removal of carious tissue and further studies of caries removal using lasers are indicated.
Remove Restoration
The Er: YAG laser is suitable for the removal of cement, composite and glass ionomer (Dostalova et al, 1998; Gimbel, 2000).. The efficiency of ablation is comparable to that of enamel and dentin. Lasers should not be used for ablation, however, amalgam restorations, due to potential release of mercury vapor. The Er: YAG laser is not capable of removing gold crowns, cast restorations and ceramic materials because of the low absorption of these materials and reflection of laser light (Keller et al., 1998). These limitations highlight the need for adequate operator training in the use of lasers.
Etching
Laser Etching is assessed as an alternative to etching enamel and dentin. The Er: YAG laser produces micro-explosions during hard tissue ablation, resulting in microscopic and macroscopic irregularities. These micro-irregularities to the enamel micro-retentive and a mechanism of adhesion without acid-etching to offer. It has been shown that adhesion to dental hard tissues after Er: YAG laser etching is inferior to that obtained after conventional etching (Martinez-Insua et al., 2000). These authors attributed the weaker bond strength the composite with laser-etched enamel and dentine in the presence of underground canyons after the laser radiation. This crack is not seen in conventional etched surface. The surface fissures contributed to the high prevalence of associated tooth fractures in the binding of both the laser-etched enamel and dentin.
A similar conclusion was drawn from a study that compared Shear (SBS) of composite resin to dentin surfaces after different treatments (Ceballos et al, 2001) .. These authors reported that acid etched specimens achieved the highest SBS values, while laser treatment showed the lowest SBS results. These findings suggest that extensive cracking caused by laser surgery and the resulting poor adhesion may outweigh the perceived benefits of laser etching.
Treatment of dentin hypersensitivity
Dentin hypersensitivity is one of the most common complaints in dental practice. Different treatment options, such as the application of concentrated fluoride to the exposed dentin tubules seal have been tested to treat the condition. However, the success rate be significantly improved by the ongoing review of lasers in hard tissue applications. A comparison of the desensitizing effects of an Er: YAG laser with that of a conventional system cervically desensitize hypersensitive dentin exposure (Schwarz et. al., 2002) showed that desensitization of hypersensitive dentine with an Er: YAG laser is effective, and maintenance of a positive outcome is more extended than other means.
Caries Prevention
Several studies have examined the possibility of using laser to prevent dental caries (Hossain et al, 2000;. Apel et al, 2003).. It is believed that laser irradiation of dental hard tissue changes the relationship between calcium phosphate, carbonate reduces phosphorus ratio, and leads to the formation of more stable and less acid-soluble compounds, reduce susceptibility to acid attack and caries. Laboratory studies have shown that enamel surfaces exposed to laser irradiation more acid resistant non-laser treated surfaces (Watanabe et al, 2001;. Arimoto et al, 2001) ..
The degree of protection against caries progression by the one-time first laser treatment was reported by a similar daily fluoride treatment fluoride toothpaste (Featherstone, 2000). The threshold pH for enamel dissolution was reportedly reduced from 5.5 to 4.8 and the hard tooth tissue was four times more resistant to acid dissolution. However, the actual mechanism of acid resistance by laser irradiation is still unclear and studies, particularly in vivo to test progress is needed.
Bleach
The goal of laser bleaching is an effective power bleaching process using the most efficient source of energy to achieve without adverse effects (Sun, 2000). Power bleaching is rooted in the use of high intensity light to the temperature of hydrogen peroxide increase, accelerating the chemical process of bleaching. The FDA approved standards for teeth whitening is missing three dental laser wavelengths: argon, CO2 and the most recent 980-nm GaAIAs diode. There are currently no reports on the use of Er: YAG laser bleaching techniques. The wavelength of the Er: YAG laser may be unsuitable for the procedures, but it is an area that would be investigated.
CONCLUSION
The Er: YAG laser has been found applications in areas such as cavity preparation, the removal of caries and restorations and enamel etching. However, the benefits and limitations of Er: YAG laser treatments are not yet fully documented. Windows seem of opportunity for the Er: YAG laser in a variety of dental applications. Lasers can mean cavity design and preparation based on the development of adhesive dentistry.
REFERENCES
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Aoki A, Ishikawa I, Yamada T, Otsuki M, Watanabe H, Tagami J, Ando Y and Yamamoto H (1998). Comparison between Er: YAG laser and conventional technique for root caries treatment in nitro. J Dent Res 6: 1404-1414.
Aoki A, Watanabe H, Ishikawa I (1998). Er: YAG clinical experience in Japan: review of the scientific studies. SPIE 3248: 40-45.
Apel C, Schafer C, Gutknecht N (2003). Demineralization of Er: YAG and Er, Cr: YSGG Laser-Prepared Enamel Cavities in vitro. Caries Res 37: 34-37.
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About the Author
Oral And Maxillofacial Pathologist
Are there grammatical errors in this German section?
Jeden Tag habe ich die Fußböden gekehrt und das war sehr langweilig aber notwendig. An meinem drittenTag hat eine Katze diabetic named George angekommen. War Schwarz, grantig und sehr krank und hat oft die Tierarzt angegriffen ER. Das hat sie nicht gut gefallen! Ich habe an meinem Endlich mich bei meinen Kollegen Tag für Ihre Hilfe und Geduld Herzlich und ich mich ein bisschen thanks have traugrig gefühlt. Ich will zurückkehren, weil ich eine Woche Wunder pressure gehabt und ich habe eine NOR will Tierärztin Sein (. thanks:
Yes. But only a few. Here is the correction. I corrected the sentences in drawing: "An meinem Kam Tag Dritten eine Katze diabetic behalf of George. "Das hat nicht gut gefallen Ihnen" (here you confused them with them) "Ich habe mich an meinem letzten Tag bei meinen Kollegen und Hilfe für Ihre Geduld und Herzlich thanks bißchen war ich ein Traurig. (See where the verb and object are put, yes you can say " I feel sad "in German, but usually you just say:" I am sad ") ich eine Woche standard for miracle gehabt habe und NOR will ever Tierärztin Werden means "(zurückkehren good" Weil Ich will wieder bowls, bowls wieder more appropriate because you come back, but you will not have permanent residence) (I think you wanted to say: "I still want to be a veterinarian," but this is still better translated as "Immer NOR", it indicates that this experience change of heart, and you have to say, "Oh" at the end because you want to be, but in the future. English synonym would be "become a veterinarian) Trust me, I am German and know that my language
Gotta Give ‘em Hope (1/2)
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