Topics of the day:
1. Re: Coolpix 5400 - unable to focus on tooth
I'm using the 4500, do not know if they have the same focusing ability, but there is a trick when you do macro focusing. The “flower” icon shown on the screen will be white-yellow-white when you press the zoom button. It will only focus when the icon is yellow to get the very near object on. For the standard upper, lower and sides view, I push the zoom to the tele end (optical, do not use the digital tele function, bad image quality), icon white, a pleasant distance to take the shot . When you want to shoot any particular tooth or the gingival condition, you have to press the zoom button until it turns to yellow and then place the lens very close to the tooth, depending on how big you want it and do auto-focus. It's in the manual and I looked hard to have found it. And, somebody just asked me the same question a few days ago.
Besides that, my 4500 is somewhat slow in macro auto-focus, the lens will move to the end then walk back to where it should have stopped, need some patience.
I use the built-in flash exclusively, no problem at all, just need some practice. J (You may have to adjust the white balance and the light metering method (spot metering or center weighted) to properly shoot a single tooth.
By the way, recently I started including the occlusal plane in the upper and lower mirror shots. In this way, you have a better feeling of the lower Curve of Spee, which is not easily seen in the side views.
Hope this will help.
Taipei , Taiwan
Dear Paul, This came up with a new referring dentist who has been around awhile but is new to my area. I have a patient on pretx recall and he kindly advised the parent that the tongue thrust had to be treated with referral to a speech pathologist. Obviously, I was negligent in this area of orthodontics and the parent should seek another opinion. Just one of the problems that one has to deal with in day to day practice. As it turns out I had previously treated the father of this patient and the mother went ape sh*t at the general dentist. Would it be possible for you to tell us all why your signature block has changed?
Thanks Charlie Ruff
Jean Marc Retrouvey McGill UIniversity Montreal Canada
Paul Thomas is correct about "Tongue thrust" and his question, "do teeth respond to light continuous forces or intermittent forces (tongue thrust)??" is a marvelous insight, because the answer is, "of course, teeth move with light continuous pressure and RESIST heavy intermittent forces".
If this were not true, we would quite literally chew our teeth out of the bone. Bruxers would have all the maxillary teeth impacted in their sinuses. Headgears would move teeth.
I have always treated open bites as if the tongue thrust swallow was secondary to the open bite, not vice versa. It's what I was taught at Temple, and I don't worry much about treating open bites. I practice in an area where people are still sent for "tongue training" to hopefully quash a biologic swallowing reflex. What a waste of time and effort. One cannot swallow without thrusting one's tongue if an open bite is present. Think about it; a food bolus would be squirted out between the incisors unless lip and tongue contact seals the open bite. a "tongue thrust" is a normal biologic response to a dentoalveolar deformity.
Many clinicians have studied the phenomenon of more rapid tooth movement with light continuous forces. Johnson, Begg, Jarabak, and Miura showed impressive results before the present arena of titanium alloys. Prof. Miura's bone culture video, shown at an AAO meeting over ten years ago, demonstrated how light forces in the culture of living bone caused an increase in cell activity, but after a certain level the osteoblasts conglomerated (like pac men) and became giant macrophage like cells. He placed a miniature Sony video camera in a living culture. It was like scuba diving in the ocean - everything in motion. Alive. Watching this, I realized with religious certainty that every effort must be made to generate light continuous force. The macrophage activity is certainly involved in root resorption. Since using light titanium wires, we never see root resorption. Leaving arches in place for many months teaches one the folly of always wanting to move up the wire sequence.
I once had a patient escape for a year while retracting six anteriors on an edgewise arch with sliding mechanics. Even with a stretched Alastik chain, when she returned a year later the case was finished, the open bite closed, and the archwire protruded 7mm on each side! That was in the 1970's. I went from 4 week appointments to 6 week intervals after that. Now we go 8 weeks. Light forces not only work, the patients rarely experience pain. This fits with Miura's bone culture research.
I recently attended a Dwight Damon course in New Orleans which came to the same conclusion. Interestingly, Dwight said that he felt the widening of a narrow arch on open bite cases made room for the tongue to assume a more normal posture, so he not only sees few recurring open bites, but is doing far less LeFort maxillary surgery. So, at least two orthodontists agree with Dr Thomas.
Thank you, Paul, for the suucinct and pointed question.
Dick Carter orthodontist Portland OR USA
I recently had this patient come to my office with relapse of the lower incisors. However as you can see there is a bonded .0195 deadsoft twist (pentaflex) wire(ORMCO) which had been passively bonded in place about 4 months earlier. A couple of weeks latter I had another patient who had been in retainers for 12 months come in with almost identically the same relapse(same tooth and rotation...coincidence???).
I would like to ask the group the following questions: What in is going on here? What type of material/technique must I apply in order to prevent this from happening in my other patients?
Regards, Paul Castella
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