Local anesthetic news

Summer was once again approaching and while unlike the anticipation and eagerness I usually enjoyed each November, as I journeyed to my
Caribbean retreat for my fix of ultra violet rays, yet there was something almost homeopathic and  calming about the aging hammock with a good book and the almost deathly silence of summer by the lake.

On my usual November trip south, the captain would put us through  the “g force” as he challenged the physics of gravity prior to lift-off. I often thought how Albert Einstein could have ever imagined what it would have been like to travel along side the speed of light when my main concern was focused on whether this de-iced 700,000 lbs monster would continue to gain altitude. However as true to form the falling leaves of red and gold faded into white fluffy cumulus which seemed to be void of density as the shining machine sliced through them as effortless as a knife through butter. There you go.  

Life above the 49^th parallel had lasting memories for me. I lived the best of both worlds. Snow shoveling was replaced by an early walk where I summonsed my younger balancing skills at playing hopscotch through the sharp edged seashells being caressed by each gentle wave. In contrast, summer was spent mostly reclining in a hammock which over the years had formed itself like a large latex glove around my girth with each increasing year.  This posture allowed me together with my book of the day to blend in with the sparsely placed pine furniture in the large and opened verandah which surrounded the cottage on three sides. open and almost oblivious to the distant hum of a power boat on the lake.

Winter, albeit relaxing and therapeutic, was in deep contrast to the silence one experienced on most lakes north of the 49^th parallel. The mere experience for most northern tourists to afford a
Caribbean vacation was seen as a right of passage to gave way to any Freudian inhibition which may have not been completely resolved. In addition, there was the cooling and refreshing rum punch mixtures added to the rhythmic sound of the “steel band” made it a powerful prescription of feeling entitled to shed not only one’s pent-up stress, but at times parts of their already skimpy apparel. This resulting atmosphere is what most scholars of psychology refer to as the emerging passive-aggressive behavior. There you go.

In preparation for my summer retreat during the month of June, I was like the proverbial bull in the china store as I maneuvered my mini shopping cart from aisle to aisle through my favorite book store. This store offered an atmosphere not unlike a trade show with rows and rows of draped individual small tables throughout the aisles which seemed to add that much more square footage to advertise and promote authors and new releases. These arcades and display tables were managed independently by their own sales associates, a title by which they preferred to be addressed. There you go. 

It was noticeably busy for a mid week morning in June. I carefully rechecked my BlackBerry organizer which for the most part tagged along with me like a faithful poodle with its unconditional love. From to time it would vibrate or other times it would emit a childlike whine to inform me of some event I had previously entered and may have completely forgotten about it. I lovingly referred to it as my dementia levee which faithfully protected any memory cells from overflowing my aging brain’s levee. A tap or two on  the sensitive touch screen revealed  nothing exceptional or urgent other than a memo to remind me to make a date to see the movie “Sex and the City” With Sarah Jessica Parker, Kim Cattrall. There you go. 

Why then was this excessive marketing atmosphere so evident throughout the store? Did the book industry secretly generate a Tiger Woods’ moment of mass marketing?  This certainly would have been the best kept secret, yet the solution was facing me right between the eyes. Historically, increased activity at book stores and movie houses has proven to be an accurate and reliable early leading indicator of impending recession as people at large have more free time. Ironically some business benefit from recession in the same way as the demand for steel increases during periods of war. 

Suspense novels are my passion and among others there were two on my short  list – namely “A prisoner of birth” by Jeffrey Archer and “The Pillars of the Earth” by Ken Follet. I also keep in touch and have a burning desire to be current with professional journals and especially editorials which, with some basic writing skills and strategetly placed references can be confused as scientific material. 

Over the many years of reading, I have developed an almost Sherlock Holmes analytical personality for articles. No more so than dentists are impulsively attracted to “the work” on one’s teeth or an architect inspecting the symmetry of a well placed keystone. These editorials/articles can often be detected by the format of their presentation, which is usually in the form of a question rather than the more accepted form of peer reviewed scientific study complete with investigating phenomena or purpose, an accepted methodology protocol and a conclusion. The pure sciences are becoming more and more diluted as such editorials begin their long “hear-say” or gossip walk through the hallowed corridors of famed teaching institutions.  Such articles presented under the guise of scientific material are for the most part self serving and do little to advance clinical efficacy with less unforeseen mishaps.  

However, there are the pundits of an evolving world where analytic jurisprudence is popular and where asking questions like, “What is law?” “What are the criteria for legal validity?” or “What is the relationship between law and morality?” and other such questions that legal philosophers may engage. (Wiki). 

An article this summer caught my attention under the heading of ethics and jurisprudence.  Here goes that question format - “Informed consent for Local Anesthesia - is it necessary?” There is implied dictum which takes the blame away from the operator and places it on a compound (amides) which dentists have been using successfully since 1947 to induce local anesthesia. If ever there was a case for longitudinal and sample size data, our stats people would have a heyday.   

Life styles through all aspects has changed and dental offices were no exception. I was as attentive to my oral health as I was to my physical health and over the  years I had noticed gradual subtle changes such as more pre clinical involvement with hygienists but perception is reality. I also noticed the office in greater detail. The Italian leather couches, slate tile floors and backlit etched glass in the patient lounge, exuded a definite warmth and elegant atmosphere. My dentist was considered to be one of the best, hence the ambience to go with her status. 

From the patient lounge I  was taken into a room with soft music and current magazines like Ophra, Vogue, Sports Illustrated, which all appeared to have been delivered that very morning. The dentist greeted me and after some small talk, asked me to place a tiny pill under my tongue which she explained would dissolve in a few minutes. Her assistant returned in about half an hour and led me into the operatory. By this time I was feeling very relaxed and comfortable.The local anesthetic solution was delivered through a computer-like electric tooth brush (minus the brush tip) and I felt absolutely nothing…no stick, not anything. I felt very relaxed throughout the procedure.  

This is where, in my humble opinion, and together with my graduate degree in pharmacy, may leave room for a clinical study to determine the use of oral or even intravenous sedation in general dentistry. The question is whether to circumvent the pain associated with what some dentists refer to as “pumping”. Is there need for added pharmacological interventions ( use of muscle relaxants) when a slower delivery ( 60 seconds) would have proven just as effective and with reduced cost to the office?  The term “ Infants practicing on mom’s high heels’ is probably not inappropriate here.  

To suggest a case for advocating informed consent for the use of local anesthetics after 60 years of successful clinical use in dentistry appears less substantive phenomena to identify such rare sequellae such as temporary amaurosis, paresthesia and even death which would seem to be classified as operator error rather than of a biochemical origin.  All clinical evidence would seem to beg the question. “Does this track record reasonably qualify to put local anesthetics (amides) under curfew or to “throw them under the bus?”

There is without doubt in general dentistry, a need to address the needle phobic patient, however a sudden move to give patients a “high” may increase patient traffic  prone to chemical addictiveness as the word get around, but with consequences not every dentist is willing to spend time, effort, legal and peer review in their selective associations. 

Anesthetics and aesthetics — they even sound as though they work together. Informed consent seems rather like infants practicing on mom’s high heels.  However for general dentistry with limited experience of these  powerful opioid analgesic with a potency approximately 81 times that of morphine (wiki) may increase the traffic you may live to regret.

Comments to author.  mailto:localanesthetics@yahoo.ca    M.Sc. PharmD. CCPE   WWW.Anestheticnews.com

This is my confession. I am a twenty four year old female of average build. I run five kilometers every day and I alpine ski in the winter. I watch what I eat and would consider myself to be in good shape. However; I do have one vice which is the reason for my confession. My dental work has been fairly extensive over the years, but I have an excellent insurance plan. The work was being done on my upper right where there is a bridge. The bridge was failing hence the need for a dental assessment and treatment. On this visit I was given two shots of anesthetic within a half hour. Each shot was expelled in about 15 to 20 seconds. Through the over head monitor I could see the blanching (gum lost the pink color. It was now white). I should add this was not a store top office. This Dental Practice in which every aspect of its facilities had been intentionally designed to reflect a much more relaxed, serene and contemporary environment for the well-off patient was located in a medical building. It was outfitted with the latest toys and computerized gadgets. It was like the cockpit of an Airbus 380. At a guess I would put my dentist to be in his middle forties and to me he looked and conducted himself every bit of a successful and up-to-date dentist.

This is my confession. As a patient, on my dental visits, I want the dentist to be current on all techniques of administering the anesthetic within reason, to make my visit a pain free experience. My choice of words is deliberate because I do not want to be heavily sedated. Drugs may control fear and anxiety, but do not fully control pain. And furthermore it is said they can cause confusion and/or respiratory depression. I am also aware that sedative drugs can stay in your system for two to three days after ingestion.  Neither do I want the application of nitrous “laughing gas” since there appears to be some ambiguity surrounding the duration of how long one should be under this application. Furthermore how can I tell the scavenger system has not exceeded its service date? However having said that, I am aware that all clinicians practice to the best of their ability and are not cavalier and will not knowingly push the envelope which could cause harm to their patients. However we have heard of situations which could have been avoided. Shift does happen.   

This is my confession. After each shot he excused himself while he went to another operatory. He was darting from room to room and between taking telephone calls he was reviewing the work of his hygienist. He was busier than a one armed paper hanger. I felt somewhat neglected like an infant left imprisoned in a crib. Even the assistant left the room. I was lonely. I thought how nice it would be to climb out of the chair and stroll around the room and indulge. As I mentioned I have had above average dental work over and above regular cleaning of tartar during my college days and still do. I knew a sudden rise from the supine position would be more foreboding than the painful shots which I suffered through. Deep within me, I knew some thing had gone a rye more so on this particular appointment. After each shot the pain grew exponentially. My tissue felt expanded and throbbing. I felt the tingling and had no control of my drooling but I was not frozen. Prior to my visit I had searched the internet which said that local anesthetics are used to control regional pain through their ability to block sensitivity by preventing sodium transport across the nerve. They also mentioned that failure to block that action potential was possible either through anatomical reasons or operator errors and skill. Who am I to delve into my oral anatomical variances? I am Caucasian and my mouth does not appear to be different from people of my build. Furthermore on previous occasions I was completely frozen where the procedure was completed successfully and painlessly.

This is my confession. During one period when I was left alone as he darted to another room, my upper right jaw felt just like it was about to explode, I overheard a one sided conversation between my dentist and someone else who I guessed was also a dentist. The letters A.M.S.A. (which) meant nothing to me were as clear as a bell and for some strange reason I paid attention as a sixth sense completely took control of my very being. These letters were scorched into my memory. The constant in and out of the room where I sat and a quick probe, suddenly confirmed that something was not going according to plan. As I said, I could only hear one side of the conversation but the sweat and the look on his face spoke a thousand words. Together with the tightness and throbbing dull pain confirmed he was conferring with a colleague. I distinctly overheard the  letters A.M.S.A…silence…followed by the phrase “a regular syringe.”… Silence…then the word “twice”. Ah! Yes the conversation was about me. There was a problem.

This is my confession. A few moments of silence, then he entered without his assistant and his face said it all. As he sat and with his heels rolled his stool towards me, he reached up and turned on the overhead halogen light while focusing it at me. Not a word was spoken but this automatically prompted me to open my mouth. He probed with his gloved finger and a miniature reflector or mirror for about 5 seconds but which felt like 10 minutes. He lifted his anti splatter orange transparent eye shades and said. “I am going to refer you to a specialist friend of mine”. The bib around my neck was unclipped and he gently assisted me out of the chair. His sincerity was cloned over his face and his shoulders drooped like tender tulips on a hot day. “It will be about a week to ten days, in the mean time I will order a prescription for Ibuprofen 400 mg to be taken twice a day with a meal.” His saddened tone was strict orders that I should call him if the throbbing still persisted.

This is my confession. When I finally got home I instantly took one ibuprofen with a glass of milk because I had no appetite and the interior of my palate was too sore to chew on food anyway. I had some Tylenol and together with the Ibuprofen, I made it through the night. The letters A.M.S.A still hounded me like a puppy following my footsteps. I anxiously wanted to see what Google had to say. Wow…there were sites upon sites that discussed this technical term and there I was before my laptop like a misfit in dental school doing oral anatomy 101. However after half an hour of reading dental clinical studies, I managed to get the acronym for A.M.S.A.  To explain it would achieve nothing since it describes a special type of injection used on the upper jaw. It is apparently one of the most difficult injections to master and one of the articles suggested that it was more effectively done slowly through some sort of computerized delivery system. Why did he not have that gadget? After all, to me his operatories lacked for nothing. The dull pain was still apparent but kept under control by the pills. Could I dare have a peep at it? I was nervous and scared. I took the challenge and what I saw was gross. I immediately called his office and left a message. My call was returned at about 8:32 AM. I explained what I had seen and he calmed me by identifying the condition as palatal necrosis, which meant nothing to me. He continued; “because of the mouth is rich with a strong blood supply, together with the anti inflammatory drugs, healing will be rapid.” My dentist has a calming voice and I felt somewhat more at ease.

Now here is my confession. During my college days I would occasionally have a toke of marijuana with my friends. It is not a big deal and I still have one every now and then especially if I am anxious or apprehensive over some event. I frequently used the internet and Facebook like all young people of my age and social lifestyle. It was during my search I read that marijuana has been shown to increase the activity of liver enzymes. It so happens that local anesthetics are broken down by the liver. Is this why I was not fully frozen? Or was it one of William Shakespeare’s Comedy of Errors being played out for me. What a coincidence!  An A.M.S.A technique which is difficult at the best of times being performed on a patient who did marijuana an hour before my dental appointment!

The contents of this mail was received by this author. I contemplated for quite some time whether I should post it. As I write, the outcome was never revealed to me. There was nothing through which it could be identified. I therefore opted to post it for what it is worth. However as a pharmacist I would qualify this as “a case of one” due to non clinical input and from one side only. However it is interesting to note a few points.

Comments to author. mailto:localanesthetics@yahoo.ca   M.Sc. PharmD. CCPE  

Please visit WWW.AnestheticsNews.com       http://tinyurl.com/2bsqsz

Do you consider yourself as having fear for the dental needle? Or that you do not feel completely frozen? Most situations with which dentists are confronted today are a test of their artistic skills. The frequency with which they use all or some of these, especially  injectable approaches makes a big difference in the comfort level of the patient during and after a dental procedure. There are approximately twelve basic techniques to administer local anesthesia to the upper (maxilla) and about half that for the lower (mandible).  The more frequently each is used, the more proficient one becomes at them all. If one fails it is suggested not to modify it, but rather to move on to one of the other techniques.  

The important explanation is applicable to both patient and dentist.  There are two techniques…the Gow gates and the Akinosi which work with people like you. You should ask for one of them, since they almost never fail. If the dentist is not willing, you maybe advised to seek another opinion. Remember we are living in a world of “moi”. You should not have to undergo unnecessary pain.  Clinical situations in dentistry are to some extent, moving more in line with medical treatment, whereby the clinician is expecting some input and cooperation from the patient so that it becomes a team effort. Gone are the days where clinicians were looked upon as mystical healers. Medical doctors and dentists need that important input from patients because healing is hastened and painless when the patient understands and is actively involved.  

I encourage you to read on. It will be presented in a pleasing manner which gives you a better insight into one’s oral anatomy. The holistic approach today is that patients do better when they are involved with the whole body. This trend has been growing for many years on the medical side; however, that desire to know, has been slow on the oral health side. 

New diagnostic equipment capable of detecting certain forms of oral cancer at specific developments is starting to make a difference with the public at large.    Again it has been women who have picket up the gauntlet and are the ones most likely to ask questions. This may be more out of absolute clinical necessity, rather than by the nature of the beast. As an example women are more prone to develop grinding of the teeth and TMJ problems. 

Bruxism or grinding can be a serious problem.  When we chew our food, we can deliver a force of over 150 pounds per square inch (psi) to our teeth. But when we grind our teeth at night, there’s no food to absorb the impact, so the force on our teeth can be over 300 psi or more. That’s enough to cause permanent damage to your teeth, including cracked and chipped enamel, hairline fractures, and even wearing down of the teeth to the gum line. The enamel may become so worn that dentin inside of the tooth is exposed. If bruxism isn’t treated, it can lead to gum damage, loss of both natural teeth and restorations, and other more complicated jaw-related disorders such as the one I mentioned previously temporo-mandibular joint disorders). Over time, your teeth may become sensitive due to exposed dentin, and your jaws may even move out of proper balance. Grinding your teeth can also cause a wide variety of other symptoms including soreness and fatigue in your jaw and facial muscles, including ear and head aches. The corrective measures for bruxism involves fitted mouth guards and specific training on how to relax those muscles involved. Students attending high school and post secondary schools are very prone due to stress of meeting time lines etc.  Fortunately, these stretching exercising together with the hardware do work. As youngsters develop and life styles change, bruxism does decrease and hopefully disappears.

Whether it is true to say TMJ is seen more frequently in females than males is often questioned. The National Institute of Dental and Craniofacial Research (NIDCR) of the National Institutes of Health (NIH) indicate that over 10 million people in the
United States suffer from TMJ problems at any given time. Both men and women experience TMJ problems; however, 90 percent of those seeking treatment are women in their childbearing years. Recent research indicates that more women seek medical care for a TMJ problem than men, and women are more likely than men to report ongoing pain. Physiological differences in pain signal processing may explain why more women suffer from TMJ conditions than men.

 In baboon studies, estrogen receptors were found in the temporomandibular joints of the female baboons, none were found in the males.Recent research has focused attention on the relationship between sex hormones and pain. A study conducted by Dr. Linda LeResche,
University of
Washington in
Seattle, demonstrated that women on hormone replacement therapy were 77% more likely to seek treatment for jaw pain than those not undergoing such treatment. Also, women on oral contraceptive therapy were 19% more likely to seek treatment. Evidence is emerging in support of a biological explanation for why there are more women suffering from TMJ pain.

It maybe that the diseases which affect the TM Joints are no different, really, than the diseases which affect other joints in the human anatomy. Rheumatoid, and Osteoarthritis; Inflammation of the Joint capsule; inflammation of the Synovial fluid, torn Ligaments, perforation, or tears in the rotator cuff. Internal derangement of the Condyle Head which is the knob-like projection that can be felt when one’s bottom jaw is extended to the fullest. Incidentally that is the approximate area that your dentist may direct the needle for those patients who complain that they are difficult to freeze.

 As a pharmacist I want to focus on the mode of action of drugs. Local anesthetics are drugs and therefore we need to be as equally informed as a dentist about these solutions. We frequently get calls from dentists requesting information on possible incompatibilities and any number of possible problematic patients. While we can not diagnose or treat, we frequently may offer suggestions if called when dealing with pharmacology and especially pharmacodynamics of other combination of drugs being used concurrently. Our training has to be current especially with new drugs (either legal or illicit) entering our communities.  

Dentists have in treat all types of patients with medical disabilities and the tremendous task to accommodate these patients. Think of any normal dental visit. It is not on the same par as an appointment with our masseur therapist.             They see patients with tourettee syndrome, (Tics), grand mal seizures, spastic episodes and Down’s syndrome, just to name a few.  

To precisely place the anesthetic injection for a block requires the skill to avoid depositing the solution in a vessel, artery or a muscle. Any sudden movement could accidentally enter these areas. In my opening comments I mentioned there were well over a dozen techniques available and the more frequently they are used, gives that dentist an added advantage. 

I will reiterate, if one approach fails, then the alternative is not to modify it but rather change to one of the other techniques. There are a number of physiological and pharmacological reasons to change to another approach. The number one consideration is the sensitive pH with which one has to deal. Healthy tissue is at pH 7.4 and the anesthetic is at around 3.5. To deposit more solution will not only cause the tissue to expand and cause swelling, but will further increase acidity. It is not uncommon for some patents to have more branches of nerves than others. They all originate from one large valley. The trick is to get the main one before it branches off into many smaller ones. When you are going after a bee’s nest, you want to smoke out the “queen” then the colony of workers is disabled. 

There are other times when a kid is un-cooperative or has a disability and will not open their mouth wide enough. There is a very cool technique where the dentist can get a block even with clinched teeth.  Yet another technique resulted from the researchers of a European pharmaceutical company. I am especially proud of this drug since I was on a team which was successful in gaining acceptance for this anesthetic to get approval in Canada and the FDA in the
U.S. I have no financial or personal interest in this drug as is generically manufactured anyway. However because of its biochemical structure it can pass through bone, especially with children from the outer vestibule on to the lingual side. The beauty of such an anesthetic is that your dentist can completely freeze a kid without freezing the tongue. Recovery to sensitivity is rapid depending on the volume deposited. The more you give the longer it lasts. However as little as half a cartridge can fully freeze a patient. The article was published in JCDA under the title of Mandibular infiltration by Drs. Dudkiewicz, Schwartz and Laliberte. (Dept. of pedodontics,

McGill
University). 

The techniques of such administration are part of my webinar meetings or full live lecturers.  

Comments are welcomed to author. mailto:localanesthetics@yahoo.ca   M.Sc. PharmD. CCPE  WWW.AnestheticsNews.com

I was advised not to go into law because members of that profession were 3.6 times more likely to be depressed, than members of other professions and it’s not just because their jobs were more stressful. Job stress has little effect on happiness unless it is accompanied by a lack of control. For most professionals, such as dentistry, stress is rated at the high end of the scale. Apparently stress is evident only when results are difficult to reproduce. Dentists have to work with variables which are of an anatomical nature, hence the predictable or lack of it, puts them already at a disadvantage. This article may explain why dentists are stressed. They are caught between a rock and a hard place. On the one hand they are dealing with patients who hate the shrillness of the piercing sound of a drill or burr and on the other, the lack of scientific longitudinal studies dealing with biology vs technology. Ironically, replacing the drill, poses other biology problems which are yet to be evaluated over time. 

Lasers in some ways resemble the compound Vitamin E. In spite of the almost mystical image it has with the public, it remains one of these agents that some medical gurus have unanswered questions. The population at large says Vitamin E is good for everything but removing the grease from the kitchen sink. While the doctors are saying, “show me the clinical evidence”. When lasers were introduced for use in dental procedures it brought with it many attributes which dentists were screaming to have and were willing to pay the substantial price tag. Dentist felt if they could reduce or replace the use of drills, burs and maybe the shot, then dentistry would be perceived as less painful and improve traffic over and above acute procedures or emergency drop-ins.

This is a good time to revisit laser analgesia and anesthesia. Women love to tell the joke about men being lost, yet failing to stop and ask for directions. They would sooner drive around in circles. Dentists also have the perception that they are doing well at being pain free. For us lay people, according to dental text books on anesthesia, there has always been those files marked “difficult to freeze”. If your dentist is within that 15% range, then to him/her that is considered zero or perfection. However would you purchase a parachute or fire extinguisher with a label that says 15 % failure rate?  Let me make it perfectly clear, it is not a bad batch of anesthetic. If it were, then almost the entire continent would have the same problem.

Dentists are trained to diagnose and treat. If the diagnosis is accurate and the treatment completed then the job is done - fait accompli. Right? Let’s be honest, if you had company over for dinner and you knew the roast was overdone or something was just not quite right, would anyone be that discourteous to say, “by the way the roast was lousy”. Patients are mostly kind and will never tell you the truth. However unless you have not been in touch with the clinical side, most people hurt at the very thought of a visit to the dentist. For me, there is a disconnect here somewhere. Your own blogs admit it. This is not a gang up.  

The reality is that above and beyond that accepted 15% failure, we are aware of the times when there is a need to reinject or reach for that painful PDL. Yet other times when the patient is “numb” except on distal lingual line of a molar. How can someone be numb and still have residual sensation? The question is rhetorical, of course, but as dentists you are aware of accessory innervations and are supposed to know how to capture all nerves. If you translated that into English, a person could be half pregnant. I am serious. One is either frozen or not. If 15 % is being accepted, when do we see the benefits of higher post graduate education, more modern university facilities and yes, the tremendous work that researchers and pharmaceutical companies have been doing since 1947 when Astra introduced the first dental cartridge with Xylocaine? We are at the same 15 % failure rate as we were then. I am wiling to be proven wrong.

Yes, you have moved on to lasers, apex locators monitors and a myriad of new composites, but is the pain and discomfort still there? Yes, implants, Invisalign and TMJ’s are all up. Lab work has taken on new dimensions, but is the pain and discomfort still there? Forgive me for rhetorical questions. One dentist said to me about laser, I am all for this technology. I have 5 years clinically behind me with the laser and I have successfully removed large alloys, composites and done crown preps, however in a low whisper confessed that he wonders whether laser anesthesia/analgesia really worked. Here is a balanced one from the other side. The patient had a fracture (N0. 11) which was an abutment to a bridge. The nerve was exposed and vital she had a note from her medic to avoid amides. The procedure involved removing the nerve which would not have been possible before laser technology and the RCT was completed successfully.

It is essential for any laser used in dentistry as an alternative to a drill be concerned about biology. What about thermal damage which a laser can cause due to the heat that is generated by the ablation of these materials. The ablation efficiency of the Er:YAG laser (?=2.94) on dental materials and one must allow for timely removal of amalgam and composite dental restorations. While it would appear that I am not cutting much slack to dentists who are working through the difficult transition, I am really on your side and wish to present to the public a better image than what exists today. From a distance what I see is a ‘first on the block mentality’. This attitude is directed at fellow dentists down the hall as well as to patients in general. Unfortunately the soldiers are not all instep. There is a disconnect. When expectations are set and results of the climax turn into a whopping anti climax, you have one hell of a task to regain that spot.

Here you are all decked out with the bells whistles and flashing colored lights in each operatory and you are wearing the amber eye protectors and the atmosphere looks impeccable, yet when the local is delivered and the expectation is that the procedure will start now, there is the wait while the dentist is off to another patient or to the hygienist. When they eventually return, that is the anti climax. After 15 minutes and I am jumping each time a gloved finger or probe enters my mouth. This never happened in dental school. You gave the local and right away your colleague was frozen. Now it is reasonable for the dentist to have to move from room to room, but the reason given is bogus. When given correctly, anesthetics work within 30 seconds at the first time. Show me in any text book where 25 seconds is the recommended delivery time. They all say 1ml/min. There is the problem.   

The term to “marinate” is not usually used by dentists, but we in pharmacy are familiar with the terminology. It basically means that the dentist may start injecting at multiple locations, with a hope that luck may be on his/her side and the patient will be frozen. My advice, speaking as a pharmacist and having the knowledge of how most drugs work, is that these multiple shots are warnings of trouble ahead. The flashing yellow is on and it may be telling you that the first injection did not do the job. The second and third (all the same drug, just by a different manufacturer’s name) will magically perform a trick from the turtle to the rabbit. (Sorry folk! this is an inside joke) your dentist may want to explain.

The dentist could sit with for an hour and explain in a similar way the salesman gave a demo at the trade show. However, you the patient are not interested with precision or smear layers. All you want is to feel nothing. To put it bluntly, you want to be fully frozen throughout the procedure. As a comparison, think of a knee implant under conscious sedation. The patient hears the saw and is aware, but there is no pain.

The biology of laser usage is still not known. It is an attempt to spare the patient the thought of a burr, drill and vibration. However, when we are dealing with living body parts, biology of structure, function, growth, origin, evolution and distribution must be factored in with longitudinal specific clinical studies. There are some prominent opinion leaders in perio who have refused to continue to lecture on closed flap crown lengthening. An area of concern is laser plume virus survival and thermal damage. Dental laser technology is here to stay because there are times when the alternative would have been general anesthesia because of severe anaphylactic shock if a local were used. However I fore see a revisit to closed technique because of the risk of bone necrosis.

A recent published article in the Journal of Periodontology, conducted at the University of Missouri, Kansas. Mullins, S.L., et al. - The purpose of this pilot study was to evaluate, by scanning electron microscopy (SEM), the surface effects of 3-CO2 laser treatment on the root surfaces and soft tissues and to investigate the effects of 3-CO2 laser on periodontal pathogenic bacteria compared to negative controls…A one-time use of the 3-CO2 laser in periodontal pockets did not sterilize or substantially reduce subgingival bacterial populations compared to negative controls.

In this age of better skills, more accurate and definitive diagnostic equipment and excellent patient compliance, there is obvious something missing when we hear the comment . . . “hang on there, we are just about finished.” Life styles have changed. That is one of my lecture topics. I hope you are not too deep in the forest to see the trees.

Comments to author. mailto:localanesthetics@yahoo.ca    M.Sc. PharmD. CCPE  

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There is a latent artist deep within each dentist.  A quote from some unknown author. One of those many quotes often heard at a spring garden party after the hectic final exam where there is a thick layer of nihilism in every glass of wine. One wonders whether such a strange marriage resulted from the “shock and awe” of having used the Crane pick elevator for the first time on a set of stubborn wisdom teeth or whether it was due to the inner peace after having finally carved the perfect anatomy, into a composite; one never know where the artist is lurking. However what we do know is that dentistry is in transition which says there is a lot more to come.

Whitening has turned into a billion dollar market in less than five years and its popularity crosses both sexes.  It’s that feeling one has when one is showing off the “bells and whistles” of their new car. It is fashionable, they feel and look great, so why not show off that bright, celebrity smile.

Bonding more commonly known as tooth-colored fillings can alter the shape or close spaces between teeth. 

Porcelain veneer is probably the talk of the young and restless. This thin coat of enamel-like porcelain bonded directly to the surface of front teeth. The finished product can dramatically change the shape, size, color and position of one’s teeth. 

Crowns somewhat less pricy, also referred to as caps are an alternative to veneers when a tooth’s structure is missing. 

Implants are now on the continuing education budget of most dentists as they develop the skill of replacing missing teeth but without having to reduce adjacent teeth.  

This gives you an overview of how the practice of dentistry has transitioned from the days of drill and fill to highly clinically skilled surgeons who practice on the one part of our anatomy that is firstly seen by our family and friends.   

However these standards do not come cheaply. Which reminds me of the lyrics attributed to George Wiedner…“when an irresistible force meets an immoveable object”, in dentistry this is called “burn out”. This leads me into my segue. By far, the subject of anesthesiology attracts the largest audience of readers to websites and blogs on a world wide basis. Pain is still by a long shot (no pun intended) the main concern associated with any visit to a dental office. In spite of every aspect of the new décor and facilities that have been intentionally designed to reflect a much more relaxed, serene and contemporary environment, the nemesis of fear still ligers.

Dentists (GP’s) are rushed to maintain the high standards associated with the main revenue generators of their practices while staying as close as possible to their schedule.It is just not humanly possible to maintain all areas. Ironically it is the delivery of the local anesthetics that pays the price. I will credit my lay readers with the following terminologies because their comments make for interesting conversation at cocktail parties. Let me be the first to admit that my brother also practices dentistry and I would not in any way be discourteous to these dedicated and skilled clinicians. I hope my observations will be taken it in the way it was intended.

However I am hearing terms like haematoma, swelling of the venous plexus, trismus, necrosis, facial paralysis, and even more recently terms like unexplained paresthesia occurring after a non invasive procedure.  Questions and blogs relating to local anesthesia, out number other problems in dentistry by as least three to one.  

Ironically  it remains the main reason why most people do not look forward to a visit with the dentist. According to Malamed’s Handbook on Local anesthesia, the rate of delivery should be at 1ml per minute. In other words the injection should take about 1.5 minutes to be properly given. The latest survey of dentists across North America is between 19 and 25 seconds and mostly as a bolus. My notes on Pharmacodynamics  would seem to lend credibility to  George Wiedner’s lyrics where “an irresistible force meets an immoveable object”. The end result is a clash between the pH of the tissue (7.4) and the pH of the local at (3.5) mostly delivered as a bolus after bone has been touched. Most of the RN base molecules are destroyed extracellularly (outside of the myelin sheath) resulting in too few base molecules crossing the sheath to effect or block sodium transport.   

The situation is compounded when there is an extra layer of fatty tissue around the sheath or a build up of lactic acid as in the case of bruxism or grinders. Getting back to the classic reasons for local anesthesia failure, the thiophene is dynamic to the benzene molecule which superceded it by some thirty five years in Canada. It is just one of these developments whereby a forward thinking company decided to invest some venture capital; I am the first to admit that pharmaceutical companies have not come up with much since 1947 when Lidocaine was introduced. Some academics strongly feel that the addition of the more lipophilic molecule, the  thiophene, may slightly increase the aromatic moity due to its spherical shape. It has been observed Malamed 3^rd Ed that the anesthesia produced by a standard dose of  any local anesthesia will vary to a great extent between different persons…(more to follow on these five classic reason for failure.) The duration of action may vary between a few minuits to up to an hour. Thinking “within the box’, here are the five basic reasons for failure:

From anecdotal reports, it would appears that once the classic litmus test has been performed and failure to achieve the expected quality of anesthesia is still less than adequate to the patient or you,  the onus is then shifted to other excuses. In my 25 years of investigating complaints, I would be hard pressed to count on the fingers of one hand the numbers of truly defective products which were as a result of the manufacturer). The manufacturing process is so regulated that a total batch of local anesthetics would suffer the same biological analysis and would involve a total recall and subsequent disposal.  Both FDA and Canada will not ship fine pharmaceticals (or finished produced) if they have not met North Amreican standards.

To support this check list, it is standard procedure for companies to donate goodwill products to be used by dentists who willingly give of their time, to work long hours in condition that are less than adequate and often not safe. These dentists must be commended.  There are numerous files of “thank you” letters and a willingness to revisit to see the fruits of their labor and the beautiful smiles of these young people. There has never been a mention of quality control deficits or any special requests for products not in standard production in the North American market. You may well say “never look a gift horse in the mouth”. These are all North American trained and practicing clinicians who have a strong desire to share their expertise with less fortunate people.

In the pharmaceutical world there is a constant evolution of drugs and their indications. Many of you may not have been around when Metronidazole was first introduced for vaginal infections, back in the sixties. Since then it has been used successfully as an antabuse-like drug for alcoholism. Today it is probably one of the most frequently prescribed compounds by peridontists. Nothing is constant. As Albert Einstein said…E=mc2. The object is to leave you with a solution and possible and update to the age old reasons for anesthetics failure.

Obviously our population is growing and the numbers of patients visiting dentist are on the increase; it therefore stands to reason that untoward incidents will follow. However I do strongly feel that pharmacodynamics needs to factored in. Delivered at the rate of 1ml/ml, if per chance a muscle or artery is slightly nicked the response from the patient would give you ample corrective time measures to avoid a dirty trismus or some other situation that eats into your time and a patient that is not too happy. So the question is whether the saving 50 seconds is worth it? 

For any dentist(s) who are willing to take this challenge, (must be timed), I will visit an Eastern location (say NY) without an honararium. I will also demonstrate a didactic on never having to give a traditional nasopalatine injection. Finally, as a bonus I will demonstrate the techniques for bone (pulpal) anesthesia known as Mandibular Infiltration.(Drs. Aaron Dudkiewicz and Stephhane Sshwartz Journal of Canada Dent Association No.1 1987). I am sure any dealer would be be eager to grab an opportunty like this. the total lecture is about 3 hours.     

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 M.Sc. PharmD. CCPE   Please visit http://www.anestheticsnews.com

WWW.AnestheticsNews.com</a>     Haynes Darlington M.Sc. PharmD.

This magic machine, our body, has the ability to respond to foreign substances just as the beautiful swan constantly removes old feathers to make room for fresh ones. Our body is like a gatekeeper in order to ensure a state of perfect homeostasis. There are times when pharmacological intervention dictates the necessity in order to correct certain ailments. For example psyllium fibre may be absent in our diet and as such, a supplement maybe required in order to reestablish normal regularity. However when a pharmacological intervention is the preferred plan of action to assist in treating a condition, it is the responsibility of the clinician or pharmacist to make sure the drug is taken properly and in accordance with the product monograph as issued by FDA or some other regulatory agency. Failing to follow these instructions can result in a response, which can be out of phase by 180 degrees.

There are numerous examples where the opposite effect is predominating when the drug is administered incorrectly. Depending on the drug, there is some minimal room for small errors. However; by and large, the rule of thumb is strict adherence to the written or spoken word by your clinician or pharmacist. Then there is the experimental phase of drugs, whereby longitudinal studies do reveal new indication for drugs that never existed when they were first investigated. Aspirin is one obvious compound that keeps going and going and going.

This article is limited to dental procedures and the drugs, which may be necessary to complete a procedure. If per chance the local anesthetic is deposited as little as one MM off the intended target, The response can produce results that are as equally scary for the patient as it is for the dentist. The fundamental response can be traced to the base or foundation of one’s every day management of stress. The “flight or fight” response, originally discovered by Harvard physiologist Walter Cannon in (1915) where the hormone adrenaline or epinephrine, secreted endogenously to produce the physiologically normal response to cope with any potentially stressful situation.

What are the saber tooth tigers of today and why are they so dangerous?

Fortunately, in our modern world we are not exposed to foraging for our daily sustenance, as did the cave man. However our hormones cannot determine the origin of stress and do respond in exactly the same way as did our fore parents.When we experience excessive stress, whether from internal worry or perceived external discomfort, bodily reaction can be triggered and can be organic or psychogenic. Nerve cells firing will activate the well-known chemical adrenaline (epinephrine). The Sympathetic Nervous System (SNS) is a branch of our autonomic nervous system. It is always active at a basal level called sympathetic tone and becomes more active during times of stress. In other words, stress is the condition that results when our environment transactions lead us to perceive a variance, whether real or not, between the demands of a situation and the resources available to us, whether they be real (biological or psychological).

Today, however, most of the saber tooth (no pun intended) tigers we encounter are not a threat to our physical survival. Today’s saber tooth tigers consist of rush hour traffic, single parent management, missing a deadline, bouncing a check or having an argument with our spouse. Nonetheless, these modern day episodes trigger the same adrenaline release. Road rage, is relatively new, but is a classic example of how powerful and alive is our autonomic nervous system. Homeostasis must be maintained at all times and our autononic nervous system will go to all extent to see that perfect condition is mainained and stable.When one has not been keeping regular visits with their dentist, there is a basic guilt that is inscribed in one’s brain. For most of us, it started during childhood. It was that nightly ritual…“have you brushed your teeth?. This question has attained, some degree of noterity status in western society. For example the book, The fairy tooth godmother where an exchange for something that has lost its usefulness (such as a tooth) for something of everlasting value carries significant personal values and  stays with one, even after one has flown the coup.

The body’s defences start to produce more endogenous epinephrine to balance the perceived threat of pain and the personal guilt that accompanies these situations. Guilt is powerful and can trigger our autonomic nervous ststem.Ironicly, the drug (local anesthetic) which the dentist most likely will be using, contains epinephrine. My earlier example of how therapeutic substances can produce more than one effect; dependant of how and where that drug is administered could not be more relevant than as in this scenario. The dentist needs to deposit the local anesthetic to bathe the nerve in such a way that it restricts or blocks any sensory impulses. This is called vasoconstriction.

It restricts the flow of blood in that specific area allowing the patient to be comfortable and without sensation of pain. Let us for the sake of comparison; see the effect of what would have been the result if the same drug had been administered into the vessel. The same drug would have affected vasodilatation or the opposite desired effect whereby anxiety and stress would be manifested. The experienced dentist has anatomical landmarks, which acts as the safety net and, which more or less reduces any accidental error.

The emphasis here is not to enter into clinical diagnosis, but rather to raise the profile of pharmacodynamics in a world of ever changing medications. Drugs administered incorrectly or directed to unintended receptors, will produce undesirable side effects.  As clinicians have found it necessary to specialize, I for see the day for specialized pharmacists. The complexity of structural algorithm of compounds is already exceeding our capacity.

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Author: M.Sc. PharmD. CCPE

Dr. Watson reviewed his technique. “How could this be”?  Am I loosing my touch? Have you ever been told by your dentist, “Gee! I seem to be off today! I cannot get you fully frozen”. There are many techniques to deposit local anesthetic into the oral cavity (tissue of the mouth) however, for this discussion; I will only deal with two basic modes, namely infiltration and complete nerve block.

Infiltration allows the dentist to freeze one or two teeth at one sitting, whereas the nerve block freezes a complete quadrant. For dental purposes the mouth is divided into four quadrants, to facilitate the numbering (of the teeth) process. Whether one is given an infiltration or a block, the desired expectation for the dentist is the same. He/she needs to be able to complete the procedure without the patient feeling no more than the initial gloved fingers of the dentist. In other words, that area of the patient’s mouth should feel like a piece of log. It is referred to as the “wooden effect” and dentists call this “class A” anesthesia.

However, according to all textbooks on dental anesthesia, failure is generally accepted to be around 15%. There are some 15 to 18 people out of 100 who will still have residual sensation, or in other words, will experience some discomfort and or pain. When this situation occurs, dentists will chat among themselves as to the reason(s) why. Discussion of marijuana comes later in the text.

There are many reasons listed, ranging from a bad batch of anesthetic solution to persons who may be classified as having accessory innervations. There could also be patients with anatomical variations, such as a wide flaring mandible and furthermore, the explanations could be an infection within the gum tissue. There are several more reasons, for example too rapid a delivery of the solution, or even an over anxious patient. These all add up to give us that 15% failure.

However, our changing lifestyles and habits are beginning to become a thorn in the sides of dentists. The growing use of cannabis…known on the street as marijuana, is being associated with the inability to achieve local anesthesia in some patients. The duration of action of local anesthetics depends primarily on the redistribution of the drug away from the site of action. This redistribution can be altered by several factors, some of which also influence onset. These considerations include diffusion away from the site, concentration, lipid solubility and protein binding qualities. This recreational habit is no longer an experimental phase of a growing youngster. It is now widespread among all walks of society.

Dentists have never had to deal with this variable factor back in the sixties and seventies. However, before he/she starts the “marinating” process, this is when the dentist deposits several different brands of anesthetic solution in numerousAreas of the mouth, hoping to strike luck. But this luck is seldom present. There is a small window with which the dentist has to play. If anesthesia is not apparent within that time, then the tissue has become too acidic and another attempt can be made later when the pH of the tissue has settled down somewhat.

Patients using cocaine should allow at lease twenty four hours, if a dental visit would involve the use of epinephrine (present in anesthetic solutions). The interaction of these two substances can cause a rise in blood pressure as well as a change in heart rhythm. The explanation of this phenomenon (marijuana) can be answered pharmacologically. Smokers of marijuana trigger high liver enzyme activity, which is known to hasten the breakdown (metabolism) of the local anesthetics. This results in a situation of not being able to sustain profound anesthesia.  Comments to localanesthetics@yahoo.ca   Please visit  http://www.anestheticsnews.com Author: M.Sc. PharmD.

References
Haas DA. Localized complications from local anaesthesia. Journal of the
California Dental Association 1998 26:677-81.
Haas DA. Drugs in dentistry. In: Canadian Pharmacists Association. Compendium of pharmaceuticals and specialties.
Ottawa: CPA, 2002, L51-54.

Are stronger medication seeping into dentistry? The usage of compounds like Versed, Demerol and Fentanyl were not so common five years ago in dentistry. Why the change? Are local anesthetics failing? or are these new meds being offered more readily?

Bupivacaine 0.5%, a tertiary amide compound commonly used to induce nerve block anesthesia in dental procedures, continues to mystify pharmacologists with its dual properties of producing analgesia after soft tissue anesthesia has worn off. Although structurally it resembles other amides such as lidocaine; however, in the hydrophilic section, it contains four extra carbons. We suspect this is responsible for its unique mode of action. This is a desirable feature, since it reduces the need to prescribe narcotic type pain killers. Its concentration of 0.5% of bupivacaine  puts it in a class of low toxicity. Another useful tip on current issues. Comments are welcomed. Contact us at localanesthetics@yahoo.ca

Toxic reaction to local anesthetics can be simplified or broken down into two categories. Those that are of a stimulatory nature and those that are of a depressive phase. 

• Stimulatory phase:
• Nervousness
• Restlessness
• Talkativeness
• Coreiform movements
• Tremors or twitching
• Clonic convulsions 

Depessive phase:

•  Hypotention
•  Bradycardia, followed by tachycardia
•  Shock
•  Loss of consciousness
•  Respiratory depression 

The use of certain illicit compounds can trigger signs of both phases. In our world of changing “life styles” unfortunately clinicians are at the fore front of facing these toxic signs.  As an example, the use of anabolic steroids.

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May be we need to get back to basics. In Pharmacology 101, we’ve heard the terms, bioavailability, antagonistic, synergistic, protein binding half life etc, etc on a daily basis. The response of any drug to produce its desired effects is directly related the manufacturer’s product monograph, having been cleared by regulatory agencies such as FDA.  Two common examples to which we can relate are the administration of nitroglycerin for angina and lorazepam (Ativan) as a mild sedative. When administered sublingually, the desired response is met. In fact, if swallowed, the affect may be compromised at best or at worst, not efficacious.Should local anesthetics be exempt from the manufacturer’s product monograph? They clearly state that administration should be at the rate of 1ml/min. Ref.  Dr. S. Malamed Fourth Edition of Local Anesthesia. Further more, to refer to “cartridges administered” rather than mg/kg, adds insult to injury, since there is a proximally 35mg in one cartridge of lidocaine and 70 mg in one cartridge of articaine Hcl. Thoughts to ponder. 

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