bluuebunny/crossref_metadata_2025 huggingface dataset:
The Unger Modification of Frechet Slot Correction Flaps
Authors: Unger Martin G.
Published: January 2017

The author has modified the original slot correction techniques described by Dr. Frechet. By carrying out these modifications, tip necrosis and extensive undermining are prevented and more permanent hair is present along the anterior margin of the second transposition flap. The author has found the modification extremely beneficial and no complications have occurred to date.
Mixed Liposculpture: Aspiration and Ultrasonic
Authors: Ferreria Julio A.
Published: January 2017

This article reviews the history of body contouring by closed fat removal from the earliest recorded description to the present. The author describes his use of combinations of different types of f at removal by aspiration, including the hand-held syringe, aspiration with a suction aspirator, and a combination of techniques he has used with ultrasonic lipolysis and fat removal.

There has been an evolution of technique in his practice of over 680 procedures. The term “mixed liposculpture” is coined to describe the use of ultrasonic lipolysis combined with aspiration of the treated tissue using low-power machine aspiration or syringe. The author's experience with this technique has resulted in less physical effort by the surgeon, more exact modeling of body contours, excellent results in liposclerosis, a more comfortable postoperative course for the patient, and fewer hematomas and complications.
Scalp Extension in the Treatment of Male Pattern Baldness
Authors: Epstein Jeffrey S. , Kabaker Sheldon S. , Puig Carlos , Maas Corey
Published: January 2017

In order to clinically assess the efficacy of tissue extension applied to scalp reduction, a prospective study was performed on 24 patients who underwent tissue extension between scalp reductions in the treatment of male pattern baldness. The accelerated rate of reduction provided by tissue extension was found to be most efficient when the extension was performed for 31 days or less after scalp reduction. The complication rate was low, while patient acceptance was high. Tissue extension is a valuable technique in scalp reduction for male pattern baldness with potential clinical applications to other situations where the harvesting of surrounding local tissue is indicated.
Evaluation of a New Kind of Dressing after Liposuction
Authors: Saylan Ziya
Published: January 2017

Bandage and compression are a very important part of the postoperative care following liposuction surgery. In this article, the author describes his use of Reston foam dressing as a postoperative compression dressing following liposuction surgery in 140 cases. Problems with the product include skin sensitivity and early removal by patients. Proper use of the product reduces the bruising and ecchymosis following surgery.
Frechet Extender, the Experience of an Additional 80 Cases
Authors: Puig Carlos J.
Published: January 2017

Presented is a prospective study of 80 scalp reductions performed incorporating the Frechet Scalp Extender into the treatment plan. Careful measurement of the pre- and postoperative bald area and the tissue removed indicates that the Frechet Extender is an effective tool and indeed increases the amount of bald area removed with multiple scalp reductions by 30%. That the compression of the bald scalp by the extender causes a thickening of the scalp by 72% has been demonstrated. The impact that the incomplete excision of this thickened bald scalp may have on the incidence of stretchback requires further study. Caution must be taken when incorporating extender devices into treatment plans that do not include total excision of the bald area.
Suction with Rotating Cannula
Authors: Mole B.
Published: January 2017

The Liposoft® device combines a traditional suction with a rotating cannula that fits into a motorized handpiece. The rotation from 0 to 400 rpm allows, in one procedure, the treatment of lipodystrophies through 360 degrees. Security is insured by an adjustable torque limitation device that prevents risk of accidental rolling up when the cannula meets resistance.

We carried out a study of 28 cases and concluded that this technique is advantageous in certain lipodystrophies (suctions from 1.5 to 8.2 liters) and in dense areas that are not easy to treat (epigastrium, knees, rolls of fat in the back). For small lipodystrophies, the Liposoft® device has no advantage that would justify its use.
Doberman's Ear Tip Plasty
Authors: Micheli-Pellegrini Valerio
Published: January 2017

The techniques of nasal-tip correction include preservation of an intact caudal segment of cartilage as a complete strip and vertical interruption of the cartilaginous arch, with or without preservation of the underlying vestibular skin, as an interrupted strip. This technique can be performed with either the nondelivery (transcartilaginous, retrograde) or the delivery approach. The “Doberman's ear” technique has both the advantages of the complete strip technique with the delivery approach and the suture stabilization of the columellar pillar as in the Goldman tip, preserving the underlying vestibular skin as in the “butterfly” (Ponti) operation.
Endoscopic Forehead and Brow-Lift Surgery for Male Patients
Authors: Geroulis Anthony J. , Kemker Bryan J.
Published: January 2017

We describe endoscopic forehead and brow-lift surgery for male patients. The endoscopic approach to the male forehead and brow-lift differs distinctly from the female lift. One difference is the consideration for placement of the incisions with respect to male pattern baldness. Another is the elevation of the brow on the orbital rim. Men often possess deeper forehead rhytids which are resistant to flattening out. The approach described allows for an easy solution by scoring of the tissue parallel to the rhytid in the subgaleal plane endoscopically. Our endoscopic technique uses both subgaleal and subperiosteal planes in a composite dissection. With this approach, the surgeon has the ability to regulate the elevation of the brow and deal with rhytids. Our experience with this method involves five male patients aged 44–56 years. Their chief complaints were excessive wrinkles of the forehead and a scowl appearance. To date, there have been no complications including infections, hair loss, or nerve injuries. All of the scars are well camouflaged within the hairline, with good wound healing. All patients have been pleased with the results of their surgery.
Innovations in Computer Imaging
Authors: Linford Ray A.
Published: January 2017

Digital imaging and recent advances in computer software and hardware provide the medical industry with a new technology for archiving photos without film and assessing patients' expectations before surgery to make sure patients receive the results they expect. Hardware advances such as the instant-access digital video capture board, advanced digital video/still cameras, and dual Pentium processors allow complex photos to be manipulated quickly so that doctors can point out subtle changes in a patient's image and realistically create end results on a screen before beginning a surgical procedure, allowing the doctor to bring the client's expectations in line with real surgical potential. Other advantages of digital imaging over traditional photography and sketching include the elimination of photo degradation over time, a lessened need for printing with the use of an on-screen image, and a limitless file room for photo storage.
The Psychological Aspects of Hair Loss Treatment: A Clinical Study of 500 Patients
Authors: Giotis K. P.
Published: January 2017

Hair loss is a psychological problem. Untreated hair loss is, of course, not detrimental to health and a person experiencing hair loss can continue to live a perfectly healthy life, unhindered. Why then is a cure so important to millions of patients and thousands of scientists? Unquestionably, it is because a psychological problem is indeed a health problem and needs to be addressed. Analysis of the reasons why hair loss disturbs the human mind is for the philosopher, the sociologist, and the anthropologist.

This study focuses on identifying the patient's approach to the problem. One thousand patients completed a questionnaire that had been devised with the help of a psychologist. The research focused on patients' awareness of the problem and of the treatments available, their reasons for seeking treatment, their biggest fears before treatment, and which age group is most concerned with hair loss.
Using Interactive Compact Disc to Reach Prospective Patients
Authors: Surgnier Jeff , Baker Sheryl
Published: January 2017

“New Patient” is an interactive compact disc (CD) program that features a host and hostess presenting motivational material and information about popular cosmetic surgery procedures. It is illustrated by fast-paced live-action video and relevant pre- and postoperative examples. The viewer presses on the interactive monitor screen to view particular topics of interest, such as face-lift, laser resurfacing, and many others. After viewing as many topics as they like, they may enter their own name and phone number for a follow-up call for more information or a consultation.

This program runs unattended on a CD player. A timer returns the program to its starting point, making it ready for the next viewer. It is housed in a locked cabinet holding the physician's brochures and is further personalized with a backlit header bearing name, address, phone number, and color picture. Systems may be placed in businesses with which the physician may have a reciprocal referral relationship. Examples are a salon where postoperative patients are sent for a makeover, or a spa where the physician has a schedule of conjoint presentations on health and beauty. A business such as “Glamour Shots,” normally in a mall setting, is another possibility. The lobby of a multispecialty clinic and the waiting room of a physician friend of a different specialty are also good locations.

Because the system runs unattended, it enhances the physician's current marketing program by speaking for the physician all day every day in strategic locations where prospective patients live, work, and play. Rather than depending on prospective patients to think of plastic surgery on their own and then search the phone book for someone to call, the interactive CD uses fun and exciting new technology to inspire them about available possibilities and provides them with the physician's name as the source for further information.
Why Evolution is Better than Revolution
Authors: Knudsen Russell
Published: January 2017

In the main, the development of modern hair restoration surgical techniques has involved a few revolutions and a number of small evolutions. These evolutions have improved upon earlier techniques after carefully analyzing both the benefits and shortcomings of these pioneer techniques. Longer-term shortcomings in surgical planning have equally demonstrated the potential dangers of aggressive radical technique changes. Modern megasessions require a gradual increase in graft numbers to accommodate the need for development of staff skills unique to these procedures. Innovation is important, but it is more safely expressed in gradual improvements to existing techniques.
Linear Grafting Using a Modified Slot Method: Introducing the Linear Punch
Authors: Hitzig Gary S. , Schwinning John P. , Handler Seymour L.
Published: January 2017

Seeking the overall goal of patient satisfaction, hair transplant surgeons have attempted to combine naturalness with density. This article presents a study of 250 hair transplant patients. In the study, linear slots are compared to other methods of creating hair transplant receptor sites. Punch grafts, micrografts, and linear grafts are compared on six parameters: healing time, time to growth, visibility after 3 weeks, hairline naturalness, hair density, and patient satisfaction. The results indicate that linear grafting using a modified slot method creates a natural swirl of hair more effectively than traditional methods. Two thousand to four thousand hairs can be transplanted in approximately 2–3 hours and healing is quick. Linear grafting avoids both the usual compression and tufting of slits associated with slit grafts and the vascularity problems associated with incisions created with lasers.
Donor Site Reharvesting in Patients Whose Donor Sites Appear Exhausted
Authors: Goldman Peter M.
Published: January 2017

With the advent of improved aesthetic hair restoration surgery using minigrafts and micrografts, many patients whose work had been previously done over the last 30 years have returned to the surgeon to see if more transplants could be done. Many such patients either felt or were told by the surgeon years ago that their donor sites were exhausted and that no further work could be done. This article discusses two methods of donor site reharvesting, punch reharvesting and strip reharvesting, that allow several more sessions of minigrafts and micrografts to be performed as well as aesthetic improvement in the patient's donor scars.
The Frontal Forelock Concept in Hair Transplantation
Authors: Beehner Michael L.
Published: January 2017

This summary of the “frontal forelock concept” is intended to clarify its role in modern hair replacement surgery. It is proposed that it is the most natural and expedient manner for transplantation in the man with severe baldness and greatly reduced donor supplies. It is moreover recommended for the younger man who is judged likely to progress to an advanced baldness stage. For the younger man, the anticipatory forelock pattern can be either in isolated form or connected to the side fringes, but it acts as part of a template for future conversion into an isolated forelock. In this article, the background and history of the forelock concept are related, definitions for the terms used relating to the forelock are clarified, six categories of suitable candidates for this procedure are proposed, and six overall benefits resulting from the use of this design are listed.
Advantages and Disadvantages of the Unger PÂTÉ Procedure
Authors: Unger Martin G.
Published: January 2017

This paper relates the results of the author's first 75 Unger PÂTÉ procedures. The technique of PÂTÉ (prolonged acute tissue expansion) has continued to be highly successful and, in this paper, is compared to both the Unger modified major scalp reduction (MMAR) and scalp extension using a Frechet extender. The advantages of the PÂTÉ procedure, including an important new use, are compared with those of both MMAR and scalp extension. Similarly, the disadvantages are also compared with those of each of these two procedures. The Unger PÂTÉ procedure has continued to gain an increasingly important role in the author's practice because, on average, 136% more scalp tissue is excised with it than with MMAR. By the same token, most patients prefer PÂTÉ to scalp extension because only one surgical procedure is required, and only slightly less tissue is removed in total. The author continues to highly recommend the Unger PÂTÉ procedure for suitable candidates.
Preservation of the Occipital Neurovascular Bundle in Extensive Scalp Lifting
Authors: Mangubat E. Antonio , Hopping Steven B. , Puig Carlos J.
Published: January 2017

The authors present their experience with a new technique of preserving the axial blood supply of the bioccipitoparietal flap used in extensive scalp lifting (ESL). ESL is a significant contribution in the treatment of advanced male pattern baldness, allowing the excision of large amounts of bald scalp in a single procedure without the use of expanders or extenders. The occipital neurovascular bundle (ONB) is traditionally ligated as a delay procedure 4—6 weeks prior to the ESL. The authors have found that preserving the ONB significantly reduces the risk of ischemic complications in ESL procedures. In fact, no flap necroses were reported in 186 procedures using this technique. Furthermore, ESL with ONB preservation was performed with no ischemic complications in 78 patients (59%) who were traditionally not considered to be candidates for ESL because they had undergone prior hair transplant procedures. It is therefore shown that ONB preservation significantly streamlines ESL by eliminating the need for a delay procedure, decreasing or eliminating ischemic complications, and increasing the flexibility and scope of ESL by allowing patients with prior hair transplantation to be candidates for the procedure.
Camouflage during Hair Transplant and Scalp Reduction Surgery
Authors: Hitzig Gary S.
Published: January 2017

Many advancements have occurred in the hair transplant and scalp reduction field, including new instruments as well as newer techniques. Despite the effectiveness of the surgical procedure, camouflage of the surgical site during the recovery period is a problem that confronts the surgeon. For some patients, residual hair can be combed or brushed to cover the operative sites, while other patients prefer to wear hats to hide the effects of surgery. Scalp camouflage is a safe and effective aid for the hair restoration patient and usually consists of wigs, sprayers, makeup, and powders. The surgeon should have knowledge of the various means of camouflage in order to inform the patient of the options for postoperative concealment.
Inactivation of the Streptococcus mutans fxpC Gene Confers Resistance to Xylitol, a Caries-preventive Natural Carbohydrate Sweetener
Authors: Benchabane H. , Lortie L.-A. , Buckley N.D. , Trahan L. , Frenette M.
Published: January 2017

Xylitol is transported by Streptococcus mutans via a constitutive phosphoenolpyruvate:fructose phosphotransferase system (PTS) composed of a IIABC protein. Spontaneous xylitol-resistant strains are depleted in constitutive fructose-PTS activity, exhibit additional phenotypes, and are associated with the caries-preventive properties of xylitol. Polymerase chain-reactions and chromosome walking were used to clone the fxp operon that codes for the constitutive fructose/xylitol-PTS. The operon contained three open reading frames: fxpA, which coded for a putative regulatory protein of the deoxyribose repressor (DeoR) family, fxpB, which coded for a 1-phosphofructokinase, and fxpC, which coded for a IIABC protein of the fructose-PTS family. Northern blot analysis revealed that these genes were co-transcribed into a 4.4-kb mRNA even in the absence of fructose. Inactivation of the fxpC gene conferred resistance to xylitol, confirming its function. The fxp operon is also present in the genomes of other xylitol-sensitive streptococci, which could explain their sensitivity to xylitol.
Carnitine in Neonatal Nutrition
Authors: Borum Peggy R.
Published: January 2017

Experimental evidence from several investigators suggests that carnitine is a conditionally essential nutrient for neonates. If camitine is a conditionally essential nutrient for the neonate, most neonates on total parenteral nutrition in the United States are not receiving adequate nutritional support. The metabolic functions of carnitine are varied and important in sev eral aspects of neonatal physiology. All neonates receiving breast milk receive dietary carnitine and most neonates receiv ing enteral infant formulas receive dietary carnitine at a level similar to that of the breast-fed neonate. However, most neonates on total parenteral nutrition receive no dietary carnitine. Investigators have been testing the working hypothesis that carnitine is a conditionally essential nutrient for the neonate for many years. This review discusses (1) data support ing the hypothesis, (2) reasons why it has not been either proved or disproved by now, and (3) the author's view of a prudent approach to dietary camitine supplementation of neonates. (J Child Neurol 1995;10(Suppl):2525-2531).
The Role of L-Carnitine in Pediatric Cardiomyopathy
Authors: Winter Susan , Jue Kenneth , Prochazka James , Francis Paul , Hamilton Wade , Linn Lawrence , Helton Edward
Published: January 2017

Metabolic and genetic factors underlie some forms of cardiomyopathy in childhood. A variety of inborn errors of metabolism can impair mitochondrial energy production, or β-oxidation, in the heart and lead to myocardial dysfunction. L-Carnitine, an essential element of β-oxidation, transports fatty acids across the mitochondrial membrane for energy production. L-Carnitine deficiency syndromes are now well described as secondary to a variety of inborn errors of metabolism and often include cardiomyopathy in the clinical picture. Despite traditional therapies for cardiomyopathy, mortality for this disorder remains at well over 50%. Review of reports of L-carnitine supplementation studies and results from our own trial underscore the importance of its role in cardiac function and demonstrates that there is likely a subpopulation of patients with cardiomyopathy responsive to L-carnitine treatment. (J Child Neurol 1995; 10(Suppl):2S45-2S5 1).
Neuromuscular Blockade in the Management of Cerebral Palsy
Authors: Koman L. Andrew , Mooney James F. , Smith Beth Paterson
Published: January 2017

Neuromuscular blocking agents-45% alcohol, 4% to 6% aqueous phenol, local anesthetics, and botulinum A toxin—have been used for many years in the evaluation and management of spasticity and movement disorders in children with cerebral palsy. Recent reports suggest that longer-acting neuromuscular blocking agents may impact positively on the natural history of dynamic deformity and improve health-related quality of life. This review includes the mechanism of action, techniques, indications, complications, and clinical outcomes associated with these agents. (J Child Neurol 1996;11(Suppl 1):S23-S28).
Radiologic Evaluation of the Dysphagic Patient
Authors: Jones Bronwyn
Published: January 2017

The radiographic evaluation of the dysphagic patient should be “tailored” to each individual depending on symptoms and the site of symptoms. Variations in technique and an approach to the interpretation of the study are presented.
The Evolution of the Evaluation and Treatment of Dysphagia across the Health Care Continuum: A Historical Perspective—Inception to Proliferation
Authors: Martin‐Harris Bonnie
Published: January 2017

The complexity of swallowing has been long appreciated and was described before the development of a sophisticated modality for direct viewing of the swallowing process. This article reviews the history of the discovery of the physiologic principles of swallowing and the development of the evaluation and management of dysphagia. Appropriate diagnostic and treatment tools are described for various environments of care, including acute‐care hospitals, subacute facilities, rehabilitation hospitals, ambulatory clinics, and home care. Differences in the delivery of dysphagia services in each setting are discussed. The author challenges dysphagia clinicians to provide care on the basis of patient need rather than reimbursement structure.
Focus on Further Education
Authors: Martin Lindsay
Published: January 2017

Our Further Education correspondent tries to bring some clarity into the murky world of fee recoupment
Management in Action
Authors: Donnelly Ray
Published: January 2017

In his second article Ray Donnelly describes a goal-setting exercise
Training Notes
Authors: Everard Bertie
Published: January 2017

Industrial style management training reveals a need for more process development
School Finance
Authors: Davies Brent
Published: January 2017

Teachers and not involved as much as they want
Primary World
Authors: Osborne Allan
Published: January 2017

Curriculum management needs to integrate not separate
Legal Update
Authors: Patricia Leighton
Published: January 2017

A review of the impact of the Social Charter on education managers
Focus on Higher Education
Authors: Kempner Thomas
Published: January 2017

A look at the balance of argument for merging institutions
School Finance
Authors: Davies Brent , Ellison Linda
Published: January 2017

Financial system should facilitate not control
The Politicisation of School Governors
Authors: Allen Frank
Published: January 2017

Enjoy the new role of governors with this fresh view of the governors' work. Henry Morris would indeed be positive about this contribution.
Positive Behaviour: Policy into Action
Authors: Harris Andrew
Published: January 2017

A ‘behaviour group’ tackles a major issue which appeared early on in the life of a new urban community college.
Getting Together: The Professional College in Action
Authors: McBride Rob
Published: January 2017

The Cambridgeshire Secondary Education Trust(CSET) shows the waytowards collegiality amongst heads in the post-LEA days.
The Living Experience of Feeling Surprised
Authors: Bunkers Sandra Schmidt
Published: January 2017

The purpose of this article is to report the finding of a Parse research method study on the universal living experience of feeling surprised. In dialogical engagement with the researcher, eight participants described the experience. The structure of the living experience of feeling surprised was found to be: Feeling surprised is stunning amazement arising with shifting fortunes, as delight amid despair surfaces with diverse involvements.
Engaging and Honoring Older Adults in Research
Authors: Baumann Steven L.
Published: January 2017

Research involving persons with cognitive changes associated with aging, including dementia, has increased dramatically in the past two decades, motivated in large part by an increasing number of older adults with such issues. Velzke in the paper that follows this introduction discusses why it is important and how to include older adults as participants in research. While focused primarily on elders and their caregivers in Scotland, the topic is a globally important one.
Philosophical Clarity and Justifying the Scope of Advanced Practice Nursing
Authors: Reed Pamela G.
Published: January 2017

The United States (US) Department of Veterans Affairs proposed a policy change for nursing practice that would grant full practice authority to advanced practice registered nurses (APRNs) nationwide. In this article, the author briefly explains this proposed policy and explores the relevance and implications of bringing philosophy into policy debates and discussions about the nature and scope of practice.
Replacement Therapy for the Prevention of Dental Disease
Authors: Hillman J.D. , Socransky S.S.
Published: January 2017

Certain laboratory-derived and naturally occurring oral bacteria are promising effector strains for the replacement therapy of dental infectious diseases. In the case of dental caries, several types of low-acid-producing mutants of Streptococcus mutans and a natural variant of S. salivarius have been found that are virtually non-cariogenic. Laboratory rats can be readily and persistently infected with these micro-organisms. Once infected, the animals become much more resistant to infection by wild-type (disease-causing) strains of S. mutans. Thus, in the laboratory rat, replacement therapy has proved successful in providing lifelong resistance to dental caries following a single application of an effector strain. Attempts to extend these findings to humans have required a search for effector strains that can both colonize well and, in addition, displace indigenous, wild-type strains of S. mutans. A mutant of a strain of S. mutans producing a bacteriocin-like molecule has been found that appears to be well-suited for this purpose.

Replacement therapy may also find a practical application in the prevention and cure of certain periodontal diseases. Hydrogen peroxide-producing streptococci are invariably found in plaque taken from healthy gingiva; they are rarely found in samples from active disease sites of patients with juvenile or refractory periodontitis. In vitro, peroxide production by these streptococci inhibits the growth of Actinobacillus actinomycetemcomitans and several other presumed periodontal pathogens. Bacterial interactions of this sort have also been directly demonstrated to occur in vivo. Thus, natural inhibitors in plaque may be essential for maintenance of periodontal health. Patients lacking such inhibitors may be treated by replacement therapy to restore the composition of their plaque flora to one that is conducive to health.
Diagnostic Imaging: Finding the Critical Features
Authors: Wagner R.F. , Insana M.F. , Grossman L.W. , Jennings R.J.
Published: January 2017

The clinical interpreter of a diagnostic image has the task of reducing the information displayed-in the order of a megabyte-to a set of classifications that convey answers to specialized diagnostic questions-in the order of just a few bits. A high-dimensional feature space is thereby reduced to a low-dimensional feature space. This paper reviews the features available in x-ray imaging, magnetic resonance imaging, and diagnostic ultrasound that derive from the geometry and the physics of the imaging process. An example is drawn from diagnostic ultrasound to demonstrate an objective assessment of a small feature space and the utility of adding back additional features. The assessment is based on the methodology of the receiver-operating characteristic (ROC) curve. Motivation is provided for use of this fundamental tool from statistical decision theory, together with definitions of the quantities involved in scoring performance.
NMR Imaging in Dentistry: Relaxation and Diffusion Studies
Authors: Skalerič U. , Dolinšek J. , Stepisnik J. , Cevc P. , Schara M.
Published: January 2017

Magnetic resonance imaging has been widely used for medical diagnosis in recent years. The knowledge of the proton spin-lattice relaxation time, T1, represents the basis for NMR imaging. In the present study, we measured T1 in saliva, gingival fluid, gingival blood, and inflamed gingiva by means of a pulsed NMR Fourier-transform spectrometer. From several measurements, we found the following average T1 values: in saliva, T1 = 2550 msec; in gingival fluid, T1 = 2085 msec; in gingival blood, T1 = 1515 msec; and in inflamed gingiva samples, T1 = 840 msec.

In addition, electron paramagnetic resonance imaging was used to demonstrate the in vitro diffusion processes of spin-labeled molecules into tooth enamel by application of the linear magnetic field gradient to a conventional EPR spectrometer. The diffusion coefficient for the nitroxide spin-labeled molecules into tooth enamel was evaluated as D = 10-7 cm2 sec-1.
Cyclic Induction and Rapid Movement of Sequential Waves of New Smooth-Ended Ameloblast Modulation Bands in Rat Incisors as Visualized By Polychrome Fluorescent Labeling and Gbha-Staining of Maturing Enamel
Authors: Smith C.E. , McKee M.D. , Nanci A.
Published: January 2017

The movement of smooth-ended ameloblast modulation bands was studied in continuously erupting Tincisors of male Wistar rats, with fluorochromes such as calcein (green), xylenol orange (red), tetracycline (yellow), and calcein blue (turquoise) used to label maturing enamel intensely at sites delimiting the location of smooth-ended ameloblasts at the time of injection. Hence, a fluorescent label of one color was injected to establish a reference position at time "0" followed by one or more fluorescent labels of different colors, or by in vitro enamel staining with glyoxal bis(2-hydroxyanil)(GBHA), at various times after the initial injection. For example, rats injected with calcein followed by xylenol orange at 10 min or two, four, six, or 12 hr later showed zero, 367, 888, 1259, and 2833 μm incisal movement, respectively, of the red bands relative to companion green fluorescent bands in the mandibular incisors. If one takes into account the eruption rate for these teeth (27.1 μm per hr), these data were indicative of a coordinated, wave-like movement of smooth-ended ameloblast modulation bands incisally along the length of the tooth at a mean rate of 243 μm per hr. Measurements and graphic plots of the distribution of smooth-ended ameloblast bands in histological sections and in GBHA-stained teeth revealed not only that such bands were positioned at all possible locations along the length of the maturation zone within a group of different teeth, but also that the average interband distance equaled about 2100 μm in the apical part of the maturation zone. Hence, new modulation waves appear to arise near the region of post-secretory transition and travel along the ameloblast layer toward the gingival margin about once every 8.5 hours. This suggests that a given cohort of ameloblasts may modulate as frequently as three times a day and complete a minimum of 45 modulation cycles by the end of enamel maturation.
Histological and Biochemical Observations of Developing Enameloid of the Sea Bream
Authors: Kawasaki K. , Shimoda S. , Fukae M.
Published: January 2017

In order to study changes in the enameloid matrix of the Sea Bream during the course of its development, we selected the developmental tooth germs of this fish as representative of three different developmental stages: "chalk-like", "cheese-like", and "soft" enameloid. The protein, calcium, and phosphate contents of each sample were analyzed. The changes of the total protein content in each sample suggest that a major part of the proteins decreased during maturation, although newly formed enameloid of the Sea Bream contains collagen and noncollagenous proteins. The existence of proteolytic activity was examined by placement of undemineralized cryostat sections of unfixed tooth germs on exposed and processed photographic films and then incubation for 30 min in a water-saturated atmosphere at 37°C. Proteolytic activity could be detected in the enameloid matrix, which appeared to be in a "cheese-like" stage. It is suggested that proteolytic enzymes play an important role in the removal of proteins during the maturation of enameloid, although the detailed mechanism of the process is still obscure.
Ultrastructural Effects of Diphosphonates On Dental Enamel
Authors: Simmelink J.W.
Published: January 2017

Initial experiments were designed to test the effects of two diphosphonates on acid dissolution of mature human enamel. Polished facets of enamel were treated with 10 mmol/L of EHDP or Cl2MDP (pH 7.4) for five min, H20-washed, acid-etched with 0.01 N lactic acid (pH 5.4) for 15 min, and examined in the scanning electron microscope. Controls were run with distilled H2O substituted for diphosphonates. In addition, the experimental window was outlined with lacquer, thus providing a reference to the original polished enamel surface. Results showed that EHDP markedly reduced enamel dissolution, with less than 1 μm of enamel removed, while Cl2MDP was similar to controls, with approximately 4-5 μm of enamel dissolved. It was decided to initiate further experiments with the objective of determining effects of diphosphonates on developing enamel during the secretory stage in rat molars.

Five-day-old animals were injected s.c. with one of the following: EHDP, ADP, Cl2MDP, or NaCl (0.9% control). The diphosphonate dosages were 2.5, 5, 10, and 20 mg P/kg. Rat incisors were also examined in initial experiments on older rats (21-day) following daily s.c. injections of EHDP. Twenty-four hr after the injections, all rats were killed by perfusion fixation and routinely prepared with and without decalcification for light and transmission electron microscopy.

Light microscopic examination of developing maxillary first molars frequently revealed subameloblastic cyst formation, which was used as an indicator of severe cellular alteration of overlying secretory ameloblasts. By this criterion, the EHDP- and ADP-treated rats showed more severe cellular effects at lower dosages (2.5 and 5 mg P/kg) than did the Cl2MDP-treated rats. In addition, when undecalcified sections were examined in the transmission electron microscope, disturbances in crystal formation were observed. Since both the cyst formation and the disturbed enamel beneath the cyst had many similarities to previous results reported on the effects of high doses of fluoride, the majority of results observed may be due to a non-specific cellular toxicity. However, some crystal growth effects appear to be specific for diphosphonates, as indicated by preliminary results with daily injections of EHDP. In the rat incisor, a definitive banding that shows both inhibition and return to more normal development within a 24-hour cycle has been detected. In the ultrastructure examination of undecalcified sections, the reaction to EHDP is clearly defined as bands of normal crystal size, electron density, and orientation alternating with disturbed bands of small crystal size and decreased electron density. The bands are approximately 2-3 μm in width.
Cements: Reactor Response
Authors: Jendresen M.D.
Published: January 2017

Many of the dental cement research needs for the future should be related to the biological environment, organic films, living organisms, and experimentation in vivo. Research in these areas will create new opportunities for physical scientists to collaborate with biological scientists, establishing research teams with composition quite different from those in the past. That compositional change could be the major change in dental cement research for the balance of the 1980's.
Endodontic Materials: Reactor Response
Authors: Hume W.R.
Published: January 2017

The need for an agreement of what constitutes success or failure in endodontic therapy in humans is emphasized. Once such agreement has been reached, major prospective studies can be undertaken in which clinical variables will be related to success or failure. Valid retrospective studies relating technique or material variables to success or failure may also be possible, if access were to be gained to a sufficient data base. Such studies would be of worth in themselves, but perhaps more importantly would then allow for correlation between in vitro laboratory studies of the same variables and clinical success or failure. Until such clinical studies are performed, the great majority of laboratory investigations into endodontic materials will be of doubtful value.
Porcelain Materials
Authors: Moffa J.P.
Published: January 2017

At no time in recent history has the interest in esthetics, biological safety, and the relative cost and efficacy of dental care been greater. In view of porcelain's desirable esthetic properties and biocompatibility, it is understandable that the major emphasis in ceramics research has been directed toward an enhancement of the strength, longevity, and esthetic properties of porcelain restorations. The ceramo-metal restoration is still the mainstay of fixed prosthodontics and finds broad application in high-stress areas and for the restoration of multiple units. Research has focused upon minimizing destructive interfacial stresses, improvement in esthetics, and the development of dispersion-strengthened porcelains. Advances in individual porcelain jacket crowns have included the use of higher strength aluminous porcelain, the use of tin-plated platinum foil, bonding porcelain to a swaged gold and palladium foil matrix, and the most recent development-castable glass ceramic materials.
Casting Metals: Reactor Response
Authors: Tuccillo J.J.
Published: January 2017

The objective of this paper was to comment on Dr. Asgar's presentation concerning "Casting Metals". An attempt was made to include those technical aspects and alloys not covered by Dr. Asgar, such as grain refinement, crown and bridge alloys, and some of the problems associated with porcelain alloy systems and how these problems forced the evolution of porcelain-fused-to-metal alloys. A re-orientation of research objectives of NIDR and academia toward product development was also suggested.
Review of Dental Impression Materials
Authors: Craig R.G.
Published: January 2017

Major advances in impression materials and their application have occurred during the last decade, with greater emphasis being placed on rubber impression materials than on dental compound, zinc oxide-eugenol, and agar and alginate. Of particular interest has been the effect of disinfection solutions on the qualities of impressions and the biocompatibility of impression materials. The principal advance in hydrocolloids has been the introduction of the agar/alginate impression technique, which has simplified the procedure and improved the quality of gypsum dies compared with those prepared in alginate impressions. The tear strength of some alginates has been improved, and some have been formulated so that the powder is dustless, thus reducing the health hazard as a result of patient inhalation of dust during the dispensing process. Polyether and silicone impression materials have been modified so that the working time, viscosity, and flexibility of the polyethers have been improved and, with the introduction of addition silicones, their accuracy has become exceptional. Although the early addition silicones liberated hydrogen after setting, thus delaying the pouring of models and dies, most addition silicones have been improved so that no hydrogen is released and dies can be poured immediately. The introduction of automatic mixing systems for addition silicones has simplified their manipulation, has reduced the number of voids in impressions, and has reduced the amount of material wasted. The incorporation of surfactants into addition silicones has made them hydrophilic, with wetting properties similar to those of polyethers, and has made pouring bubble-free gypsum dies easier.

This review is confined to published and unpublished information of the past decade. It will also suggest trends that should be anticipated in the near future based on this information. The review will not present information developed before 1975, which is available in several textbooks on dental materials by Craig (1985a), Phillips (1982), and Williams and Cunningham (1979).
Dental Impression Materials: Reactor Response
Authors: Anusavice K.J.
Published: January 2017

A review of the literature reveals an abundance of research papers which are focused on the physical properties and "simulated" clinical performance of impression materials. The three major developments during the past two decades were: (1) the introduction of the dimensionally stable addition silicones, (2) the development of dustless alginates, and (3) the reduction in technique sensitivity which resulted from the availability of automatic-mixing syringe tips. These syringe tips ensure consistently homogeneous mixtures of base and catalyst pastes with reduced waste. In addition, the more rapid mixing potential extends the traditional working time of the material.

Little progress has been made toward correlating in vitro properties with in vivo performance. Since typical in vitro studies of impression materials are conducted under nearly ideal conditions, the information derived is of relatively limited value in predicting their clinical performance under more demanding conditions. Future research should focus more on clinically relevant properties, including freedom from porosity, viscosity-time relationships, tissue displacement potential, tear strength, elastic recovery, sensitivity to storage conditions, compatibility with die stones, degradation potential after exposure to disinfectant and sterilizing solutions, and ability to be re-poured accurately.
Some Aspects of the Chemistry and Physics of Dental Resins
Authors: Braden M.
Published: January 2017

The status of denture-base poly(methylmethacrylate) (PMMA) has been reviewed, and in spite of the availability of mechanically superior injection-molded resins, it remains the material of choice. PMMA can be reinforced with fibers, the most recent being ultra-high-modulus polyethylene fibers. Various elastomer reinforced materials are also available. Alternatives to room-temperature polymerizing PMMA resins include higher methacrylates and epimine resins. High-modulus resins have been produced with Bisphenol A-glycidyl methacrylate (BisGMA) and tetrahydrofurfuryl methacrylate, involving an anti-plasticizer function. Also reviewed are room-temperature polymerizing initiators, radio-opaque resins, and studies on polymerization shrinkage.
Resins: Reactor Response
Authors: Bayne S.C.
Published: January 2017

A commentary is presented on the review paper by Dr. Braden on the state of the art of the "science of resins" in dentistry. The subject area is defined as principally including those materials involved with the denture-base applications. Recent studies involving investigations of structure and properties are noted. Most reports of properties have concentrated on physical, chemical, and mechanical properties. The limited amount of information on biological properties is noted. The absence of clinical investigations of materials performance is emphasized. Future research strategies should concentrate on areas which involve clinical research information, other product properties, and the adaptation of new technology to these applications. CAD/CAM is suggested as an example of this new technology. Finally, investigators in the area are admonished to take advantage of information management systems, to collaborate more with each other, to collaborate more with industry, and to focus more on a few promising systems in order to produce significantly better denture-base materials for clinical practice.
The Origin of Periodontal Infections
Authors: Genco R.J. , Zambon J.J. , Christersson L.A.
Published: January 2017

Periodontal diseases are recognized as bacterial infections, and some forms are associated with specific organisms, such as Actinobacillus actinomycetemcomitans in juvenile periodontitis, and Bacteroides gingivalis and others in adult periodontitis. The source of the periodontal organisms, whether they are part of the indigenous or resident flora and overgrow to become opportunistic oral pathogens, or whether they are exogenous oral pathogens, is important to determine. The chain of periodontal infection, microbial agent(s) and their transmission, and host response are reviewed with respect to the role of A. actinomycetemcomitans in localized juvenile periodontitis and B. gingivalis in adult periodontitis. The present data lead us to hypothesize that some periodontal organisms may be exogenous pathogens.

Prevention of periodontal diseases may be influenced by the knowledge of whether various forms are caused by opportunistic organisms or exogenous pathogens. If exogenous pathogens are responsible, prevention can be directed to intercepting transmission, thereby preventing colonization. On the other hand, if the organisms are opportunistic pathogens, prevention might be directed at interfering with initial acquisition of the flora earlier in life, as well as suppressing them to low levels consistent with health. For those exogenous periodontal infections, attempts at eradication and prevention of re-infection are likely to be effective. If the organisms are part of the indigenous flora, there is little hope of complete elimination of the organism.

Criteria for distinguishing exogenous periodontal pathogens from opportunistic periodontal pathogens include the prediction that exogenous pathogens would be transient members of the oral flora associated with periodontal disease, likely to be comprised of one or a few clonal types, and intrinsically virulent. In contrast, opportunistic periodontal pathogens would likely be members of the indigenous flora and would overgrow. They would likely be comprised of many clonal types, and have an intrinsically low level of virulence.