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Sparking from titanium wires
LETTERlS
781
TO THE EDITOR
wherea:s in our study the force was applied in one cycle. This force resulted in bone failure, at times through the fixation screw holes. In the specimens studied it appeared that the fixators acted as stress risers due to the poor quality of the underlying bone. All of the samples tested show similar load-deflection patterns (slope of approximately 960 N/mm) before failure. This pattern existed whether 2.0mm or 2.7-mm screws were used as lag screws or position screws. Based on these patterns of specimen failure we believe that our conclusions, as stated in the manuscript, remain valid. The load deflection pattern demonstrated that fixation failure occurred as a result of the presence of the fixators in inadequate bone. The failure pattern was the same despite the size of the screw and the method of insertion. In our opinion this demonstrated that, in these instances, the quality of the underlying bone was more important than the type of fixation used. This being the case. the location in which the screws were placed appeared to be more critical than the type of screw used. As stated on page 48 of the “neither pretapping of the receptor site nor manuscript, screw size can overcome the drawback of inadequate bone quality.” Therefore 2.0-mm positional screws seemed to be as effective as the larger screws. Unfortunately our literature search failed to capture Dr Foley’s articles, and we apologize for this oversight. We appreciate his interest in our report, and hope that this explanation helps to clarify our position. ALAN SCHWIMMER, DDS
New York, New York
SPARKINGFROM TITANIUM WIRES
To the Editor:-The readers may be interested in knowing that titanium-containing orthodontic archwires have a tendency 1.0produce sparks when cut or manipulated. I have noticed this with beta-titanium wire (TMA, Ormco, Glendora, CA), martensitic type nickel-titanium wire (Nitinol, Unitek., Monrovia, CA), and the super-elastic austenitic type of nickel-titanium wire (Ni-Ti, Ormco, Glendora, CA). This “sparking” doesn’t always occur, but I have seen it on numerous occasions, especially when the wire fractures during overzealous bending and manipulation, and during distalend cutting. I cannot recall having seen stainless steel wire behave the same way. Although nonflammable gases are now routinely used in surgery, and sparking from electrosurgery instruments is commonplace, this uncontrolled, haphazard sparking potential of titanium wire may be of interest to some readers. As a general rule, most orthodontists use rectangular stainless steel wires in orthognathic surgery patients but it is entirely possible that surgeons may be confronted with pa-
tients who have titanium-containing place at the time of surgery.
orthodontic
wires in
J. BURTON DOUGLASS, DMD Riyadh Saudi Arabia CHOOSING A PATHOLOGIST
To the Editor:-An editorial in Cutis (48: 18 I, 199 1) by John T. McCarthy, MD, and Bernard Ackerman. MD, addressed how a dermatologist should select a dermatopathologist. In essence, the authors suggested that the choice is obvious--“on the same basis as they choose one for themselves and family, ie, competence.” Many of you are aware of a double standard that some dentists use to choose an oral and maxillofacial surgeon. Difficult cases (emergencies on a late Friday afternoon, employees and family) are sent to one surgeon, whereas routine cases are sent to another. This begs the question; don’t all patients deserve the same “expert” treatment given to family and employees? The same parallels exist when an oral and maxillofacial surgeon chooses a pathologist. Hardly a week goes by without a request that we “no-charge” a biopsy on a family member or employee. Some would have us extend this courtesy to distant relatives of the “doctor next door.” Many of these clinicians do not send us their routine (paying) cases but instead send them to their local pathologist. These same clinicians periodically want us to review these biopsies for accuracy, examine radiographs, or recommend a course of treatment. Numerous reasons exist why oral and maxillofacial surgeons do not send biopsy specimens to oral pathologists; pressure from local hospitals. extended tumaround times, poor service, etc. Many Departments of Oral Pathology provide overnight Federal Express delivery of specimens, 24 hour turn-around-time, and immediate diagnosis by fax to address these issues. It is a fact of life that Departments of Oral Pathology. like all other segments of the health care system, are dependent on adequate patient (specimen) referral and appropriate reimbursement to continue to survive and prosper. In our case, as in many others, profits are used to fund residents and research as well as support faculty salaries and pay overhead. Combined with the fact that oral pathologists provide the most “expert” of care for patients undergoing biopsy for oral and maxillofacial lesions. there are very few reasons to send specimens other than to an oral pathologist. The only factor which should affect where specimens are sent is “competence.” As McCarthy and Ackerman so aptly put it, “Dermatologists know very well that superb competence is the sole criterion that they utilize to select a dermatopathologist to ‘read’ sections for the geese. The same criterion should be used for the ganders.” STEVEN D. BUDNICK, DDS
Decatur,
Georgia
781
TO THE EDITOR
wherea:s in our study the force was applied in one cycle. This force resulted in bone failure, at times through the fixation screw holes. In the specimens studied it appeared that the fixators acted as stress risers due to the poor quality of the underlying bone. All of the samples tested show similar load-deflection patterns (slope of approximately 960 N/mm) before failure. This pattern existed whether 2.0mm or 2.7-mm screws were used as lag screws or position screws. Based on these patterns of specimen failure we believe that our conclusions, as stated in the manuscript, remain valid. The load deflection pattern demonstrated that fixation failure occurred as a result of the presence of the fixators in inadequate bone. The failure pattern was the same despite the size of the screw and the method of insertion. In our opinion this demonstrated that, in these instances, the quality of the underlying bone was more important than the type of fixation used. This being the case. the location in which the screws were placed appeared to be more critical than the type of screw used. As stated on page 48 of the “neither pretapping of the receptor site nor manuscript, screw size can overcome the drawback of inadequate bone quality.” Therefore 2.0-mm positional screws seemed to be as effective as the larger screws. Unfortunately our literature search failed to capture Dr Foley’s articles, and we apologize for this oversight. We appreciate his interest in our report, and hope that this explanation helps to clarify our position. ALAN SCHWIMMER, DDS
New York, New York
SPARKINGFROM TITANIUM WIRES
To the Editor:-The readers may be interested in knowing that titanium-containing orthodontic archwires have a tendency 1.0produce sparks when cut or manipulated. I have noticed this with beta-titanium wire (TMA, Ormco, Glendora, CA), martensitic type nickel-titanium wire (Nitinol, Unitek., Monrovia, CA), and the super-elastic austenitic type of nickel-titanium wire (Ni-Ti, Ormco, Glendora, CA). This “sparking” doesn’t always occur, but I have seen it on numerous occasions, especially when the wire fractures during overzealous bending and manipulation, and during distalend cutting. I cannot recall having seen stainless steel wire behave the same way. Although nonflammable gases are now routinely used in surgery, and sparking from electrosurgery instruments is commonplace, this uncontrolled, haphazard sparking potential of titanium wire may be of interest to some readers. As a general rule, most orthodontists use rectangular stainless steel wires in orthognathic surgery patients but it is entirely possible that surgeons may be confronted with pa-
tients who have titanium-containing place at the time of surgery.
orthodontic
wires in
J. BURTON DOUGLASS, DMD Riyadh Saudi Arabia CHOOSING A PATHOLOGIST
To the Editor:-An editorial in Cutis (48: 18 I, 199 1) by John T. McCarthy, MD, and Bernard Ackerman. MD, addressed how a dermatologist should select a dermatopathologist. In essence, the authors suggested that the choice is obvious--“on the same basis as they choose one for themselves and family, ie, competence.” Many of you are aware of a double standard that some dentists use to choose an oral and maxillofacial surgeon. Difficult cases (emergencies on a late Friday afternoon, employees and family) are sent to one surgeon, whereas routine cases are sent to another. This begs the question; don’t all patients deserve the same “expert” treatment given to family and employees? The same parallels exist when an oral and maxillofacial surgeon chooses a pathologist. Hardly a week goes by without a request that we “no-charge” a biopsy on a family member or employee. Some would have us extend this courtesy to distant relatives of the “doctor next door.” Many of these clinicians do not send us their routine (paying) cases but instead send them to their local pathologist. These same clinicians periodically want us to review these biopsies for accuracy, examine radiographs, or recommend a course of treatment. Numerous reasons exist why oral and maxillofacial surgeons do not send biopsy specimens to oral pathologists; pressure from local hospitals. extended tumaround times, poor service, etc. Many Departments of Oral Pathology provide overnight Federal Express delivery of specimens, 24 hour turn-around-time, and immediate diagnosis by fax to address these issues. It is a fact of life that Departments of Oral Pathology. like all other segments of the health care system, are dependent on adequate patient (specimen) referral and appropriate reimbursement to continue to survive and prosper. In our case, as in many others, profits are used to fund residents and research as well as support faculty salaries and pay overhead. Combined with the fact that oral pathologists provide the most “expert” of care for patients undergoing biopsy for oral and maxillofacial lesions. there are very few reasons to send specimens other than to an oral pathologist. The only factor which should affect where specimens are sent is “competence.” As McCarthy and Ackerman so aptly put it, “Dermatologists know very well that superb competence is the sole criterion that they utilize to select a dermatopathologist to ‘read’ sections for the geese. The same criterion should be used for the ganders.” STEVEN D. BUDNICK, DDS
Decatur,
Georgia