Case Study: Utilizing hard and soft tissue laser technologies
UTILIZING HARD AND SOFT TISSUE LASER TECHNOLOGIES TO TREAT CARIOUS LESIONS ON PATIENT TREATED FOR A CHEMICAL DEPENDENCY PROBLEM:
2940 nm Erbium .Yag Laser is a very effective tool in treatment of hard tissue carious lesions, do its unique absorption characteristics for its chromphore or laser energy absorber is water.
The ablation of oral hard tissues with the laser is extremely precise and minimally invasive. The removal of tooth structure is done in non-contact mode. Approximately 50-125 microns is removed for each pulse. Energy is adjusted according to type of tooth structure being ablated. The more water in the substrate ,the lower the energy required to ablate the tooth structure. When working on teeth with severe carious lesions, the laser gives us the capacity to ablate quickly and efficiently. The laser does not cut. It searches out the water and basically explodes the tissue away in microns, by bringing the temperature of the water up above 100 degrees centigrade. Essentially micro-explosions are occurring.
Due to factors, which are not scientifically documented, we are able to provide laser anesthesia in most cases using a defocusing technique. This allows us to provide treatment in multiple quadrants of the mouth during the same visit. Thus minimizing any risks to those patients with chemical dependent problems.
The erbium laser does allow us to attain great hemostasis due its low coagulation efficiency. It has about 20% of the coagulation efficiency of the CO2 laser. This is due to the fact that the coagulation depth does not match up with the blood capillary diameters. For this reason we need an accessory laser to give us the necessary hemostasis when soft problems arise during a hard tissue procedure.
The diode laser( 810-1064 nm0 ,which is great coagulation tool is our laser of choice. Its chromphore is pigmentation. It has no affinity for hard tissue ablation. The CO2 laser 10,600nm, which is also a great coagulation tool, has a high affinity for hyroxy-appatite. It can cause collateral damage by generating too much heat to the surrounding tooth structure.
Do to many changes that can occur in the oral environment when there is abuse of certain drugs. One in particular termed is “Meth Mouth”. Extensive carious issues can be seen.
See Fig 1 Pre op Photo
Meth Mouth is a term that used to describe an end result of the use of Methamphetamines long and its effects on the oral environment. Both Soft tissue and Hard tissue effects. In respect to carious breakdown of the teeth, we will usually see a classic pattern of cervical caries rampant throughout the mouth. Meth mouth is reported to be distinct from all other types of oral changes caused by other forms of drugs. Many experts agree that the caustic ingredients used to produce these drugs play an integral part in the destruction occurring the mouth. A few examples would be lithium used in car batteries and phosphorus found in matches.
Methamphetamines tend to dry the mouth making the oral cavity a prime site for carious lesions to occur. In 2005 the ADA published a paper making a clear distinction between carious lesions caused by this chemical addiction and caries caused by inadequate hygiene practices. Meth mouth can initially begin when the starts to have a deleterious effect on the salivary glands. The drug is a durative of Hydrochloric acid (HCL). The drug can be snorted or smoked. Smoking the drug will immediately open up the path for enamel destruction due its high acidity levels. Meth users will have intense craving for sweets. Combine high acidity levels, high amounts of refined sugars, poor hygiene and dry mouth, we have the perfect scenario for the picture we see. (crystal meth addiction.org)
Removal of the carious lesions utilizing the 2940 nm Erbium .Yag Laser ,together with high and low speed rotary instrumentation( Laser only cuts at the tip and using a round to get into hard to reach angles necessitates conventional dental means as well.) Soft tissue laser support is also required to keep the area dry and stop and contamination (blood) of prepared site when placing the final restoration. Quite often the caries is subgingival and cervical tissue has to be removed to find intact marginal tooth structure. The soft tissue 810 diode laser will support us with adequate hemostasis.
HARD TISSUE LASER SURGERY
Traditional treatment of hard tissue dental lesions required utilization of instrumentation via mechanical means for the removal of carious lesions. Utilization of this mechanical technology (high speed hand pieces) does not allow for selective removal of specific tooth structure. The hand piece cannot differentiate enamel, from dentin to caries as it cuts. It is only our tactile mechanisms that allow to feel specific resistance levels. We cannot predict exactly how much tooth we are removing at a specific time. Utilization of Hard tissue lasers allows us to selectively ablate hard tissue based on their water contact. We can work ablate in microns instead of millimeters. This allows us to maintain the integrity of the tooth without weakening the existing supportive tooth structure. Thus the term minimally invasive dentistry.
The basic mechanism of action is based on a photothermal effect cause by the absorption of laser energy by a particular chromophore (or Absorber). In this case Water. This photothermal effect causes the ablation of tooth structure by vaporization. Temperature of the Water in the substrate reaches 100-150 degrees centigrade. This causes micro-explosions due to the expansion of the water molecule giving off steam and therefore removing the desired tooth structure in microns. Compared to the near IR lasers the outward explosion effect of the erbium class of lasers results in minimal thermal diffusion though the tooth structure.
Lets discuss how this Hard Tissue Laser Works.
- The Erbium .Yag laser is a free running pulsed lasers .It tremendously peak energy powers working in microseconds with a large relaxation period to keep the pulp from overheating. This free running pulse emission results in rapid vaporization.
- Every Laser has an Active Medium. This also gives it the name.
- The photons produced are specific for this wavelength
- A Pumping Mechanism or Excitation is necessary to maintain an adequate number of photons at high energy levels. This is essential for laser energy production.
- The Hard tissue lasers are located in the Mid –Invisable-IR Range, of the EMS Spectrum.
- This energy has a very affinity for hydroxyl-apatite.
- Its cuts by the process of ablation as previously mentioned.
- A water coolant spray is necessary to minimize Pulpal Temperature increases and mitigate against pulpal necrosis. This water also flushes out debris from the previous ablation so that the laser does not stall due to sludge bulid-up, and also cause potential increase in temperature.
- The ideal way to cut hard tissue is holding the tip perpendicular to the enamel rods
- Removal of tissue is selective ablation based on Water content of the substrate.
- The less water in the tissue, the greater the amount of energy needed for the ablation process to occur.
- Sound can be an effective tool in determining the tooth structure being ablated. Less water more energy needed, greater the pooping sound
- Anywhere from 50-125 micron of tooth structure are removed during each laser pulse
- Content of Hard Tissue
a. Enamel 12% Water 85% mineral Carbonated Hydroxy Apatite, 3% organic proteins
b.Dentin 20% water,33& protein, Mostlycollagen,44% mineral
c,Caries 60% water
- Comparison Between Laser and High Speed Hand piece
Laser Air Driven Hand piece
1. No Micro-fractures 1. Not selective when cutting
2. Selective ablation 2. Heat transfer
3. Ablation rate of enamel 20% of air turbine 3. Faster
4 Bacterial reduction 4. Produces micro fractures
5. Minimal heat transfer
16. Reduction of pain with ER.YAG LASER
a. The reports of pain free dentistry with lasers are relatively anecdotal.
b. Studies by Keller and Hibst on 103 Patients resulted in only 6% requesting local anesthesia
c. Chaiyavej et al. Found that the Erbium.YAG,like the air turbine preparation caused neural response in Both the A and C intradental fibers
d. Possible reasons for laser anesthesia ( pulpal analgesia)
17. Gate Theory; Interference with Neural Stimulus Propagation
18. Lack of tactile and thermal stimulation (Non-Contact Laser application)
This slide depicts the entire range of the EMS Spectrum. The Yellow area shows the soft laser range
This Slide Depicts The Different Lasers Used in Dentistry . The Erbiums are in the mid-infra range.
This photo shows one of Erbium lasers on the Market
The following slide shows the different absorption levels for specific chromophores.
CASE STUDY LASER ASSISTED HARD TISSUE TREATMENT FOR EXTENSIVE CARIES DUE TO CHEMICAL ABUSE;
DIAGNOSIS and TREATMENT PLANNING
24 YR. OLD FEMALE PATIENT PRESENTS WITH EXTENSIVE CARIOUS LESIONS CONSISTANT WITH METH MOUTH SYNDROME. MEDICAL HISTORY INCLUDES TOBACCO USE, ONE PACK PER DAY, AND HIGH ANXIETY. FINANCIAL AND TIME CONSTRANTS. LIVES IN THE SOUTHEASTERN USA. HAD TWO DAYS TO COMPLETE AS MUCH OF THE DENTISTRY AS POSSIBLE. TO TRY AND MINIMIZE THE AMOUNT OF LOCAL ANESTHETIC, AS MENTIONED PREVIOUSLY WE CAN IN MANY INSTANCES ACHIEVE ADEQUATE PULPAL ANESTHESIA.TREATMENT PLAN WAS TO PROVIDE 26 COMPOSITE RESTORATIONS. WITH MANY OF THE CERVICAL LESIONS BEING SUB-GINGIVAL ADEQUATE HEMOSTASIS WOULD BE NECESSARY TO PROVIDE A CLEAN SITE FOR THE FINAL RESTORATIONS. CONSIDERING ALL OF DYNAMICS, WE DECIDE TO USE BOTH HARD AND SOFT TISSUE LASERS TO PROVIDE EFFICIENT AND SAFE TREATMENT FOR THE PATIENT.
LASER EQUIPMENT UTILIZED AND SETTINGS
FOR THE HARD TISSUE ABLATION PROCEDURES WE USED A ERBIUM.YAG LASER, FREE RUNNING PULSED, WE UTILIZED BOTH 600U 30 DEGREE AND 80 DEGREE QUARTZ TIPS. SETTINGS FOR ENAMEL 15Hz, 400 MJ, DENTIN 15HZ, 200 MJ, CARIES 15HZ, 100MJ. AVERAGE POWER FOR ENAMEL 6W,DENTIN 3W,CARIES 2W. ENERGY ADJUSTED FOR DIFFERENT WATER CONTENT. REMOVAL OF SOFT TISSUE WITH ERBIUM SETTING USED 40 HZ, 40MJ AVERAGE POWER 1.6W ALL NON-CONTACT
FOR ABLATION OF TISSUE TAGS AND HEMOSTASIS 810 NM DIODE USED. CW (CONTINOUS WAVE). SETTING 1.2 W. CONTACT LASER