Some Important Developments Presently Influencing Dental Health In America
by C. C. Bass, M.D. New Orleans, La.
Studies promoted by facilities to which the author has had access at The School of Medicine, Tulane University of Louisiana, and by aid for equipment and supplies provided by the University.
Several things have occurred in the past which adversely influence, in one way or another, the dental health and welfare of the American people at the present time; and will continue to do so in the nearby future. I wish to direct attention to four separate developments that have taken place during the past forty years which will have to be discredited and discontinued, and their misleading influences will have to be overcome for people to enjoy the highest degree of oral cleanliness and dental health. They are: 1. Improper methods (Charters, Stillman, others) of brushing the teeth; 2. Placing undue emphasis upon brushing the teeth immediately after each meal; 3. Artificial fluoridation of communal water supplies; 4. Topical application of fluorides.
1-Improper Methods (Charters, Stillman, others) Of Brushing The Teeth
During the first quarter of the present century much attention was directed to methods of brushing the teeth, with the idea of massaging the gums at the same time. Alfred Fones was a pioneer in the field of oral hygiene, and especially in training and in promoting the work of the dental hygienist. He established the first school1,2 for their training. He also published detailed instructions3 for the home care of the mouth, and got out several promotional pamphlets and a textbook intended especially for dental hygienists. A reprint of the fourth edition of this book,4 in 1942, describes the same method of brushing the teeth as he first described.3 It has been referred to as the "big circle" method and consists particularly of brushing the buccal and labial sides of the teeth, held in occlusion, with a wide circular movement to include also the gums high and low over the teeth. A large soft brush was used with the idea of massaging but not injuring the gums. To his credit Fones advocated vigorous scrubbing of the occlusal surfaces of the teeth and, as a part of his mouth hygiene, he also included cleaning of the proximal surfaces about the contact areas with dental floss. In the Charters method5,6 the bristles are directed into the embrasures between the teeth, pointed somewhat occlusalward, the sides and not the ends resting upon the gums. Short rotary movement of the brush is supposed to clean the teeth within the sulci and at the same time to produce "an ideal massage of the gums" by pressure with the sides of the bristles. He warns especially "do not allow the points of the bristles to rest upon the gums". In the Stillman method7-9 the bristles are placed obliquely to the long axis of the teeth or at an angle to the gingival surface and directed apically, the bristle ends resting partly on the gingivae and partly on the cervical portion of the teeth. "The bristles should never be pointed at right angles to the surface of the gingivae, for in this position they may cause puncture. Pressure on the gingivae is desired with the least amount of friction or injury." "This act is repeated several times and the handle is given a slight rotary motion but not enough to cause the bristle ends to move from the positions in which they were first placed".
Numerous modifications, especially of the Stillman method, have been advocated and taught. The chief of these provides that the sides and ends of the bristles be applied in a sweeping movement towards the occlusal, from above downward for the uppers and from below upward for the lowers. Many dentists believe and insist that this method must be followed. In a book of more than 700 pages on the use and abuse of the toothbrush Hirshfeld10 inclines to prefer the Charters method which differs from the Stillman method essentially in the direction of the bristle ends - in the former they point occlusally, in the latter apically. He says these two methods are superior to others generally in that the stroke used is shorter and less forceful, thus minimizing the "tendency to gingival traumatization and tooth abrasion". Throughout his discussion, the idea prevails of taking care not to puncture or injure the gums with the ends of the bristles. He urges especially to avoid "penetration of the gingival crevices by the bristle ends". It should be noted that this is exactly the opposite of what is absolutely necessary. The tooth must be cleaned within the gingival crevice. This can be done, to the extent it can be done with the brush, only by applying the ends of the bristles of the right kind of brush11 to the areas on the tooth within the crevice to be cleaned. These improper methods or modifications of them have been advocated by leading authorities and taught in dental schools so long and so positively until they have become firmly established in dental practice. The dentist who advises his patients in this regard recommends the particular method or modification which he accepts as the best. In papers or in discussions wherein the method of brushing is given the Charters or Stillman method or a modified Charters or Stillman method is usually specified. Often the speaker refrains from being specific and calls it "an approved method" or "an accepted method", neither of which means anything definite. One does not find in the writings of the originators and promoters of these method3 of brushing the teeth any indication that their opinions in this regard were based upon accurate personal knowledge and experience as to the local microscopic etiological and pathologIcal conditions in the two principal diseases affecting the teeth-caries and periodontoclasia. These diseases are caused by microscopic organisms, the lesions at first are microscopic in extent, they advance microscopically, the tissues involved are composed of microscopic elements, and the destructive processes are microchemical. Therefore, one can know of his own knowledge and understand these conditions upon which effective prevention must be based, only through microscopic studies and experience. Less than 25 per cent of the loss of teeth in this country results from caries; more than 75 per cent from periodontoclasia. Periodontoclasia begins in childhood and is a universal disease of man. Everyone, at anytime, has lesions of some stage of activity and advancement, and these can be demonstrated by proper microscopic examination of suitable material from the locations concerned. Practically all people sooner or later lose their teeth from this disease, if they live long enough. It prevails among people of all races and in all levels of civilization, the rate of progress being influenced by the oral hygiene habits and methods of the individual. It affects the most cultured and intellectual people of the world and even more severely, the primitive races,12-14 including the African bushman15 whose habits and characteristics, in many respects, are more like those of lower animals than of man. Caries is limited to people whose diet contains the necessary fermentable (mostly refined) carbohydrates. The initiation and progress of the lesions of this disease also are influenced largely by the effectiveness of the personal oral hygiene habits of the individual. At the present time very few people know and accurately follow, or have any way to learn the exact method which must be followed to prevent caries. Consequently, almost all people in this country have more or less caries lesions, and most of these tend to progress. in time, even though they receive the best treatment and restorations that can be given. Many of the teeth in which caries lesions originated in childhood are ultimately lost, however good the dental service may be. This can be prevented only by preventing the lesions before they start.
The purpose of personal oral hygiene is maintenance of oral cleanliness and prevention of both caries and periodontoclasia, and their consequences. The purpose is accomplished however only to the extent the method or technic, of which proper use of an appropriate toothbrush is an important part, removes and prevents re-accumulation of harmful amounts of the essential etiological material at the locations where the lesions of these diseases originate and advance. The confusion and inadequacy of information regarding these two principal diseases is indicated in testimony16 given by Dr. Harry Lyons on February 29, 1956 before a subcommittee of the U. S. Senate. He called attention to the vast and complex problems of tooth decay and its it infectious sequelae, and stated that "the so-called gum diseases are essentially complete mysteries as far as their causes and prevention are concerned". He was speaking as president-elect of the American Dental Association, as dean of the School of Dentistry of the Medical College of Virginia, and as a member of the National Advisory Dental Research Council for the National Institute of Dental Research. Caries lesions originate only at locations where heavy bacterial film (plaque material) is continuously present. To prevent initiation and advancement of such lesions it is necessary to prevent or minimize the accumulation and retention of this material which is composed largely of filamentous types of micro-organisms having one end attached to the tooth surface and the other extending outward towards the surface of the film mass. This characteristic has been illustrated17-18 and has been adequately documented18 by references to numerous other specific illustrations in the literature. These fundamental facts can be confirmed by microscopic examination of plaque material removed from extracted tooth specimens or of sections of enamel cuticle removed with plaque attached. Removal of this material with the toothbrush from the locations to which the ends of the bristles can be applied, is only partial at best. There are many organisms left and these tend to grow and re-accumulate, thus renewing the film pad or plaque. By repeating the cleaning at suitable intervals harmful re-accumulation and caries producing conditions at the particular locations are prevented. Almost all caries lesions in young people (under adult age) originate either in the pit and fissure depressions on the occlusal surfaces or on the proximal surfaces around the contact area. The vulnerable areas on the occlusal surfaces can be cleaned well by vigorous application of the ends of the bristles of the toothbrush. It is physically impossible to clean the proximal surfaces where caries lesions originate by any method of brushing with any kind of brush. These areas can be cleaned adequately only by passing the right kind of dental floss19 through the contact area between the teeth and back out, thereby removing most of the material which is essential for caries activity. The next most frequent location for caries lesions to originate is in the cervical region at the cemento-enamel junction. Normally this junction line is covered by the epithelial attachment20 and is not exposed to the necessary conditions (bacterial plaque) for caries. After the gum recedes sufficiently (usually not before adult age) to expose this line at any place caries lesions may begin, if the location is not kept sufficiently clean. This can be done by the use of the toothbrush only to the extent the ends of the bristles of suitable characteristics are vigorously applied to the areas to be cleaned. Please note that this is exactly the opposite of the improper methods of brushing referred to above.
The bristles of the brush cannot reach and clean the interproximal cervical region. This can be done only by proper application of the right kind of dental floss19 to the particular location. Periodontoclasia (gingivitis, "pyorrhoea alveolaris", "periodontal disease") is a purely local, continuous, inflammatory disease resulting from local etiological conditions. At anytime after a tooth has erupted and attained its occlusal level, suitable material from the gingival crevices, especially the interproximal crevices, always contains from a few to many pus cells; and sections of tissue from this location show more or less inflammation upon microscopic examination. The intensity or activity of this early stage inflammation (gingivitis) varies greatly in different people and in different locations in the same mouth, influenced largely by the oral hygiene conditions present. This early unrecognized and usually symptomless gingivitis constitutes the early stage of a progressive pathological process which continues to advance and never ends until the involved tooth is finally lost (extracted or exfollicated), usually after middle life, sometimes earlier. Much confusion has resulted from failure to recognize the early stage of this disease. Kronfeld21 says "the presence of a small number of inflammatory cells in the sub-epithelial tissues can be considered as indicating a gingivitis; but if it is, almost every human gingival crevice would have to be considered pathological which would only cause confusion". All periodontoclasia lesions begin at the gingival margin where bacterial material (plaque) is continuously produced and is retained on the tooth at the entrance to the gingival crevice. The bacterial mass tends to advance (grow) into the crevice and cause irritation and microscopic inflammation (gingivitis) of the crevicular epithelial tissue resting against it. In time concretions (mostly calculus) form on the surface of the tooth in the deeper part of the bacterial mass. This is composed largely of filamentous types of micro-organisms attached to the tooth. The foreign material on the tooth and extending into the crevice now consists of the hard concretion overlaid by the film of growing bacterial material, and this is mechanically more irritating to the gingival tissue resting against it. The inflammation and suppuration resulting from the advancement of this foreign material on the surface of the tooth within the crevice (now a "pyorrhoea" lesion) continues (usually over long periods of time) and the attachment of the gum on the tooth recedes.20 As the process advances inflammation and resorption of the supporting tissues - periodontal tissue and alveolar bone - ensue and progress as long as each particular tooth is retained. At all times this foreign material is found present on the surface of the tooth within the crevice, thus making the tooth itself, in effect, a foreign body extending into the chronically inflamed and suppurating surrounding tissue. This fundamental fact has been illustrated17,18 and has been adequately documented18 by references to numerous other specific illustrations in the literature. It can be confirmed by microscopic examination, also with the dissecting microscope, of specimens of extracted teeth suitably stained to bring out the landmark22 which indicate the location of the outer border of the epithelial attachment. This locates the very bottom of the lesion when the tooth was in the mouth. The bacterial film always extends to this line23 and the underlying subgingival calculus extends24 almost to it.
The only way by which the early stages of this disease and further advancement of existing lesions can be prevented is by cleaning the teeth within the gingival crevices sufficiently frequently to prevent re-accumulation of the etiological foreign material. This can be done with the toothbrush only to the extent the bristles of appropriate dimensions11 are directed into the crevices and reach the material to be removed. This is exactly the opposite of the improper methods of brushing referred to above. The bristles can be directed into the exposed crevices in the sulci between the teeth but they cannot be applied to material in the deeper part of the interproximal crevices. This can be removed by the use of the right kind of dental floss25 carried to the very bottom of the crevice, but in no other way now known. Scales of calculus must be removed by a dentist who understands the conditions that exist. Although calculus does not reform in locations that are cleaned daily, occasional cleaning and rechecking by the dentist is needed to discover any locations that may have been missed by the daily routine. A method of personal oral hygiene based upon the above indicated fundamental facts has been designed, by which the highest degree of oral cleanliness and dental health can be maintained. Both caries and periodontoclasia are practically prevented and further advancement of existing lesions, especially early stage lesions, is substantially retarded or prevented. I have referred to this method as "the necessary method of personal oral hygiene",17 "the right method of personal oral hygiene","an effective method of personal oral hygiene".18 In speaking to dentists who have learned and are teaching it to their patients or to people who know and follow it, I usually refer to it as "our method of personal oral hygiene". Anyone who knows of his own knowledge and understands the local microscopic etiological and pathological conditions in the two principal diseases already knows in advance that approximately this exact method is necessary and that any neglect or deviation from it would be less effective to the extent of such neglect or deviation. Improper methods of brushing the teeth not only are not effective but teaching and promoting them misleads people and detracts from their learning and following the method of personal oral hygiene which is absolutely necessary.