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Gnathology
Angle's occlusion and the cusp-fossa ideal of organic occlusion.39 He developed a system of measurement whereby the maximum number of cusp-fossa relationships could be established. He improved on Angle's occlusion by obtaining from 5 to 10 fossa relationships. This was an excellent attempt to meet cusp-fossa requirements in spite of the handicaps of tooth-size discrepancies. Cusp-fossa relations are always preferable to cusp-embrasure occlusion, but are not always achievable. This is when occlusal adjustment pro cedures become necessary or else all teeth will not be in contact and there will have to be diaste mas someplace.
O rth op ed ic g n a th o lo g y J a c k L. H o c k e l, D D S, e d 485 p a g e s w ith illu stra tio n s. In d e x . A p p e n d ix. $160. C hicago, Q u in te s se n c e P u b lish in g Co, Inc, 1983
The opening sentence of this book de scribes the removable Crozat appliance as “the basic cause and effect of orthopedic gnathology,” and it is Crozat therapy that is the book’s central theme. Because the editor states that “It is assumed that the reader has some fam iliarity w ith the Crozat appliance,” this book is not a monograph for the beginning practitio ner, but a reference manual for the sophis ticated clinician. However, the assumed level of reader sophistication signifi cantly varies throughout the book. Addi tionally, the editor uses the book to criticize traditional orthodontic conven tion, aligning gnathologists, orthopedic gnathologists, dental kinesiologists, cra n ial o s te o p a th s , n u tritio n is ts , and myofunctional therapists against conven tional university-trained orthodontists. If these vagaries are overcome, the reader can enjoy an otherwise solid text. For the benefit of the uninitiated, the first three chapters cover the jargon and tenets of orthopedic gnathology. The def inition of organic occlusion and the his tory of Crozat therapy are carefully de tailed; however, the presentation of the biologic basis of orthopedic change is less thorough. Under diagnosis and treatment planning, the Whip-mix articulator with properly mounted casts is neatly pre sented as the orthopedic gnathologist’s primary diagnostic tool, and the use of Pont’s index is emphasized. These points are further advanced in the chapter on craniom axillary symmetry. However, principles of treatment planning and ini tial appliance design and adjustment are summarized and assume prior knowl edge of the reader. This is also true of the chapter on Crozat mechanics. In contrast, several disciplines are pre-
The opinions and com m ents expressed by review ers are th eir ow n and do not represent the views of the Editor or of the A m erican Dental Association. Publishers of books and distributors of audiovisual m aterials and film s are invited to subm it new items for review in th is section. •Titles preceded by an asterisk are available from th e ADA library.
I an Organic Occlus
lieOcclusion, the Goal of Gnathology
teeth are present the closure stoppers prevent wear and possible separation of the front teeth. Secondly, the first stage of protrusive disclusion. the first millimeter out of centric, cannot be gained by the incisors if they are not within .001" of con tact due to excessive horizontal overlap (overjet) or the lack of overbite (Fig. 1-12a and b). In this in stance. when an orthopedic correction cannot be made, the contact of the mesial inclinesof the low er buccal cusps can disclude the mandible by detruding beneath the distal inclines of the upper mesial marginal ridge. As Stuart noted, the upper ridges "behave with their opponents as if they were small incisors."41Thelower first bicuspidcan protrude in a similar relationship to the upper cuspid (Fig. 1-13a and b) to assist the disclusion.
IV. Primary Marginal Ridge Contacts Six of the ten characteristics are related to upperto-lower tooth relations. Uniform centric contact and cusp-fossa relations have been dicussed. Numbers. IV. V. VI and VII are the remaining four. Figure 1-9a diagrammed the fit of a lower buccal cusp into an upper mesial fossa This is a sagittal plane projection. Please note the contact on the distal incline of the upper mesial marginal ridge against the mesial marginal ridge of the lower buc cal cusp. The distal marginal ridge of the upper lingual cusp has a similar contact with the mesial incline of the opposing distal marginal ridge. Stuart has labelled this type of contact a closure stopper becauseit resists theforward component of the arc of closure, first described by Stallard in 1923» (Fig. 1-10). Figure 1-11is a horizontal plane illustration of the
Fig. 1-13 Diagram of the first can be provided by marginal ridge cont A: Second bicuspids
closure stoppers. These contacts are so named because they are the first contacts of closure in a gnathological wax-up. There are more closure stoppers than are shown here because all distal inclinecontacts on the upper and all mesial incline contacts on the lower are closure stoppers. Each closure stopper is opposed by an equalizer to be described below. Twosignificant aspects of these contacts are noteworthy. If posterior teethare lost e splayed. When |
In a cusp-fossa occlusion every closure-stopper is coupled with a contact on the distal incline of a lower triangular ridge or the mesial incline of an upper triangular ridge. This contributes a mesiodistal stability to the occlusion. Figure 1-9a illus trates in the sagittal plane a lower buccal cusp and the two contacts it has with the upper marginal (closure-stopper) and triangular (equalizer) ridges. Every cusp has four ridges: a mesial marginal ridge, a distal marginal ridge, a triangular ridgeand a central ridge. Three out of these four ridges can contact an opposing cusp in cusp-fossa occlu sion. In restorative gnathology this tripodism is a goal because a tripod is the most stable system in mechanics. Inorthopedic gnathology this isalso a goal whenever possible. Shaw noted that "in unworn or little worn denti tions the total area of the maximum intermaxillary contact in occlusion does not normally exceed three or four square millimeters.'42 Since all ridges are rounded in all three dimensions, the cusps take on the form of a gothic pyramid.43Two rounded surfaces meet at a point, so the contacts will be small. If this type of tangency is obtained there will be a built-in adjustability to wear. The cusp tips will be preserved and the occlusion will 31
O rthopedic gnathology
sented from a more elementary perspec tive. Myofunctional therapy is presented in classic “cookbook” form for the busy practitioner. It is an excellent, wellillustrated reference source for the inter ested practitioner. The negative aspects of myofunctional therapy’s history are, unfortunately, simply dismissed as re sulting from the actions of “unqualified personnel with improper training.” The chapter on nutrition includes discussion of respiration and feeding practices that blend well with the anthropologic and physiologic material included. Despite definition of cephalometrics as a secondary, and perhaps useless, diag nostic tool, a lengthy presentation of basic cephalometric anatomy precedes a summary of the Sassouni and JarabakBjork analyses. Similarly, although the chapter on functional jaw orthopedics is well written and illustrated, it seems al most out of place because of its basic, in troductory type of presentation. How ever, it is the inclusion of these materials, and craniognathic im plications, that qualify this as a text on orthopedic g n ath o lo g y ra th e r th a n ju st C rozat therapy. Not unexpectedly, the strongest sec tions of the text are those directed at clini cal practice. The chapter on early arch developm ent provides both excellent
treatm ent rationale and illustration of clinical methodology. This is also true of the case history presentations. The chap ter on record-keeping and practice man agement is also well done, and could be used as a training manual for office per sonnel. Overall, this text provides a thorough review of the current status of a rapidly developing clinical discipline. It should be included in the reading of anyone en gaged in Crozat therapy. John G. Crawford, DDS, MS Dr. Crawford is form er director, division of growth and developm ent, U niversity of Illinois College of Dentistry; he is in the private p rac tice of p ed ia tric dentistry an d orthodontics, Oak Park, 111.
Prosthetic treatment R e a litie s o f d e n ta l th era p y — a d e ta ile d r e v ie w o f p er io d o n ta l p r o sth e tic treat m en t R o n a ld L . M o lo ff, D D S, a n d S te p h e n D. S tein , DDS 4 5 9 p a g e s w ith illu s tr a tio n s . I n d e x . $78. C hicago, Q u in te s se n c e P u b lish in g Co, Inc, 1982
Drs. Moloff and Stein have authored an excellent atlas format text reviewing JADA, Vol. 108, A pril 1984 ■ 649
P U B L IC A T IO N
R E V IE W S
periodontal prosthetic treatment. In the first chapter the authors present C om m en t “Basic concepts of periodontics,” while in the second chapter they deal with clin Basic Goals of Occlusion ical objectives and include some excel lent questions, for example, “why do den tists have such difficulty critically ob serving their own work?”. In the third chapter the authors explain and illustrate some advanced periodontal A book by Celenza and Nasedkin. Occlusion. The State o l the Art. reported on a meeting that brought together some o f the most renowned authorities in the field. It prosthetic cases involving the interplay becomes evident upon reading the book that all these men are perfectionists who execute their different concepts and techniques with similar precision. Though of numerous specialists (such as the peri there are differing opinions regarding condylar position and ideal occlusal designodontists, oral and maxillofacial sur some prefer a full gnathologic approach to reconstructive dentistry, others develop relatively flat occlusal patterns-all agree the operator m ust be able to guide the geons, fixed and removable prosthodon mandible into a reproducible position that consistently yields accurate records that can be transferred to an articulator. W hether the articulator be fu lly or semi-adjust tists, endodontists, and general practitio able is dependent upon the clinician and his concepts of occlusion, The actual un derstanding o f th e concept o f occlusion should not have anything to do with one's ners) in the treatment. This chapter, enti articulator. In Comment, p. 141. we describe the basic centric landmarks sought in o rder to tled “Team dentistry,” emphasizes the achieve a "functional" occlusion. The restoration of a single tooth o r small section is proper sequence of treatment involving dictated by th e existing jaw position and occlusion. This is only attempted if there are no signs o f periodontal pathology o r TMJ dysfunction. When the existing occlusion the various specialists, cooperation be has lost stability becauseofthedeform itiesof disease, recordsare taken to develop the occlusion in the position o f centric relation. Definition of this position varies with tween the various specialists, and the im the clinician and, although not scientifically proven, it is safe to say centric relation must be a reproducible position with th e condyles probably being in the m ost supe portant role of the patient in maintenance rior position o f the glenoid fossa. Once models are mounted in centric relation, the clinician can make accurate decisions regarding modification o f crown-to-root ra (home care) of the desired result. tio, incisal guidance and cuspal inclination. With the foregoing fundamentals estab Cases of posterior bite collapse, together with moderate to advanced periodontitis are accompanied by significant bone loss, mobility and flaring and extrusion of the lished, the authors cite in the fourth chap 168 ter some 24 case reports with hundreds of excellent black and white and color illus trations, and a descriptive text and com Realities of dental therapy ments in a lecture-slide format. The authors are to be complimented and the text is recommended not only to ADDITIONS TO THE LIBRARY graduate students in periodontics and T h e b o o k s lis te d h e r e h a v e b e e n r e c e n tly prosthodontics but to all dentists whose a d d e d to th e B u re a u co llectio n . R e q u e s ts f o r primary interest is in periodontal or pros- th is m a te ria l, a v a ila b le on lo a n to a ll m e m thodontic care, or both. b e rs o f th e A sso c ia tio n , s h o u ld b e a d d r e s s e d Charles H. Casey, DDS to th e B u re a u o f L ib r a r y S e rv ic e s . T h e re is n o Dr. Casey is professor of fixed prosthodon tics, departm ent of restorative dentistry, the University of Texas Health Science Center at Houston, Dental Branch, an d consultant in fixed prosthodontics, department of dental oncology, division of surgical services, M. D. A nderson Hospital and T um or Institute, H ous ton.
ANNOTATION T h e fo llo w in g a n n o ta tio n h a s b e e n p r e p a r e d b y A le th a A . K o w itz. T h e p u r p o s e o f th is a n n o ta tio n is to p r o v id e a n im m e d ia te , b rie f, d e sc rip tio n o f a n e w p u b lic a tio n .
C h ron ic p a in an d TMJ sy n d ro m e G e ra ld N. S m e r n o ff, D D S 12 p a g e s w ith illu stra tio n s. $4. B e th e sd a , M d, A r ie l E n te rp rise s, 1983
This small, attractive dental health edu cation pamphlet explains some of the fac tors relating to the complex problem that is the Temporomandibular Joint (TMJ) syndrome. Brief descriptions of possible symptoms are given as are descriptions of the anatomy of the joints and the anatomy of the human body relating to the syn drome. Diagnosis and possible therapies are briefly discussed with the caution that TMJ dysfunction is a problem best ad dressed by the trained professional. 650 ■ JADA, Vol. 108, A pril 1984
c h a rg e f o r b o rro w in g b o o ks, b u t th e r e is a s e r v ic e c h a rg e o f $10 f o r m e m b e r s , $15 f o r n o n m e m b e r s f o r e a c h p a c k a g e l ib r a r y . M e m b e r s o f th e A sso c ia tio n w h o w ish to p u r c h a se b o o k s m u s t e n c lo se a c h e c k o r m o n e y o r d e r w ith th e r e q u e s t. I llin o is r e s id e n ts s h o u ld a d d 7% re ta ile r s u se ta x to th e p u r c h a se p r ic e o f b o o k s. B o o k p r ic e s a re su b je c t to c h a n g e w ith o u t n o tic e in a c c o rd a n c e w ith c h a n g e in p u b lis h e r ’s p ric es, a n d b o o k s a re n o t r e tu r n a b le f o r c re d it. N e a r ly a ll th e d e n ta l jo u r n a ls p u b lis h e d in th e w o rld a t p r e s e n t a re a v a ila b le to m e m b e r s on lo a n . A lis t o f b o o k s, p a c k a g e lib r a r ie s , a n d jo u r n a ls is a v a ila b le on re q u e st.
Books Emergency p hysician’s guide to dental care. Berry, H.W., ed. Philadelphia, U niversity of Pennsylvania Press, 1983. 122 pp Factors an d m echanism s influencing bone growth: proceedings of the international conference held at the U niversity of Cali fornia Center for the H ealth Sciences, Los Angeles, Jan 5-7, 1982. Dixon, A.D., and Sarnat, B.G., eds. (Progress in clinical and biological research, vol 101). New York, Alan R. Liss, Inc, C1982. $97.57 Hill, C.M., and Morris, P.J. General anaesthesia and sedation in dentistry. (Dental practi tioner handbook, no. 32.) Bristol, John G. W right, 1983. 151 pp Hobsley, M. Color atlas of parotidectom y. (Surgical procedures, vol 1.) Oradell, NJ, M edical Economics Books, cl983. 96 pp. $29.06
In te rn a tio n a l C onference on M ono/luoro-
Comment
teeth (Fig. 4-176). This bone resorption and extrusion of the anterior teeth result in an unfavorable crown-to-root ratio. Mechanically, these teeth function at a deficit due to secondary occlusal trauma. O ur main objective is to shorten the teeth, thus creat ing a more favorable ratio. A s the anterior teeth are shortened, a decrease in the in cisal guidance is observed. This decrease means fe wer horizontal (excursive) forces transmitted through the teeth to th e periodontium(Fig. 4-177). By establishing a lingual platform with centric stops where necessary, forces are directed more ver tically through the long axis of the teeth. This can only be achieved after a more fa vorable crown-to-root ratio and decreased incisal guidance are accomplished. Quite often, orthodontic retraction o f the maxillary and mandibular anterior teeth is also necessary. 169
p h o sp h ate (1983: Boston). Monofluorophosphate perspectives: the com pound and its past, present, and future applica tion: proceedings of the International Con ference on M onofluorophosphate, Boston, June 9-10,1983. Gron, P., andE ricsson, Y., eds. (Caries research, vol 17, su p p l 1) Basel, Sw itzerland, S. Karger, 1983. 135 PP International Symposium on Ceramics (1st: 1982: New Orleans). Dental ceramics: pro ceedings of the First International Sym posium on Ceramics. McLean, J.W., ed. Chicago, Q uintessence Publishing Co, Inc, C1983. 541 pp. $143.08
Johnson, D.R., and Moore, W.J. Anatomy for
dental students. Oxford, Oxford Univer sity Press, 1983. 266 pp. $30.59 Kohn, H.B. Clinical applications of hypnosis: a m a n u a l fo r th e h e a lth p ro fe s s io n a l. Springfield, 111, Charles C Thomas, 1983. 135 pp Manson, J.D. An outline of periodontics. (Den tal practitioner handbook, no. 33.) Bristol, John G. Wright, 1983. 207 pp A p h y sician ’s guide to gearing up for retire m ent. A m erican M edical A ssociation. Chicago, American M edical Association, 1982. 1 vol (loose-leaf). $39.95 Textbook of oral and maxillofacial surgery, ed 6. Kruger, G.O., ed. St. Louis, C. V. Mosb Co, 1984. 782 pp. $42 Treatment of hemifacial m icrosom ia. Harvold, E.P.; Yargervik, K.; an d Chierici, G., eds.
PU B L IC A T IO N
REVIEW S
N ew York, Alan R. Liss, C1983. 247 pp. $49.37 Weiser, R.S., and Myrvik, Q.N. Fundamentals of im munology, ed 2. Philadelphia, Lea & Febiger, 1984. 510 pp Yellow pages: a professional advertiser’s guide to maximum impact yellow pages adver tising. Phoenix, The Advertising Dentist, TAD Enterprises, 1983. 58 pp. $25
Periodicals AADC Beacon, American Association of Den tal Consultants, Baltimore AGD Dentistry —in general! Iowa City Akyurt Saglik Ocagi Bulteni, Ankara, Turkey B oston U n ive rsity M edical Center, Centerscope, Concord, Mass CD: Career Directions for Dental Kygienists, Holmdel, NJ California D ental Laboratory Association (South) Communicator, Los Angeles Cleveland Dental Society Bulletin, Cleveland (formerly: The Bulletin of the Cleveland
Dental Society) The Coit Tower, Northern California State Den tal Hygienists Association, San Francisco (formerly: San Francisco Component) College of Dental Surgeons of Saskatchewan Newsletter, Saskatchewan, Canada Concept 80’s, Missouri Academy of General Dentistry
Curette Courier: Newsletter of the Pinellas County Dental Hygienists’ Society, Palm Harbor, Calif The DDS’ Alert, Tulsa, Okla The Dallas Dental News, Dallas County Dental Assistants Society, Irving, Tex Dayton Dentistry, Dayton, Ohio (formerly: The
Dayton Dental Society Bulletin) Dental Medicine, Journal of the Israel Dental Association, Tel Aviv Dental Society of Waukesha County Newslet ter, Delafield, Wis (formerly: Waukesha County Society Newsletter) Dentist/investor, Fairbum, Ga Detroit Dental Clinic Club Newsletter, Dear born, Mich The Family Dentist, Ohio Academy of General Dentistry, Toledo, Ohio Floss flyer: ASDHA Newsletter, Alaska State Dental Hygienists’ Association, Anchor age, Alaska Focus on Dental Computers, Cherry Hill, NJ Forum o f Esthetic Dentistry, Chicago GP News, Southern California Academy of General Dentistry, Santa Monica (for merly: Southern California Academ y of General Dentistry, GP News) Ka Leo, Hawaii Dental Hygienists’ Association, Aiea, Hawaii (formerly: HDHA: Hawaii
Dental Hygienists’ Association) MCDS Journal, Multnomah County Dental So ciety, Portland, Ore (formerly: MCDS bul letin} NCODS Articulator, North Central Ohio Dental Society NCSDHA P eninsula Component, Northern California State Dental Hygienists’ Asso ciation News Line/University o f Michigan, School of Dentistry, Ann Arbor The North Carolina Dental Review, Chapel Hill, NC The Review of A kyurt Health Centre Bulletin, Ankara, Turkey Trends and Techniques in the Contemporary Dental Laboratory, Alexandria, Va 652 ■ JADA, Vol. 108, April 1984
Dentalese I t ’s here. 1984. George Orwell predicted that by now a triumphant tyranny would have completed its debasement of the English language. Orwell had watched the process with dismay, writing: Defenseless villages are bombarded from the air, the inhabitants driven out into the countryside, the cattle machine-gunned, the huts set on fire with incendiary bullets: this is called pacification.
Orwell treasured precise words. He believed they have not only the power to explain, to persuade, and to delight, but also the power to corrupt, to control, and to enslave. Remember, the final victory of Big Brother would have been achieved when everyone believed the three slogans of the Party: WAR IS PEACE FREEDOM IS SLAVERY IGNORANCE IS STRENGTH
Similarly, Graves and Hodge, in The Reader over Your Shoulder, argued: No writer of English can be sure of using exactly the right words even in a single context, and even after 20 or 30 years of selfeducation. But he should at least act on the assumption that there is always an exactly right word, or combination of words, for his purpose—which he w ill gratefully recognize as such if it happens to occur to him; and that though he may not always find the right word, he can at least learn . . . to avoid the quite wrong ones. And even the not quite wrong.
Mark Twain thought the effect of an “intensely” right word was electrify ing in a physical and even spiritual way. When we allow ourselves to select the “quite wrong word,” the effect is dismal. Recently, in a bulletin of a county dental society, I was astonished to read: Pres. Elect, Dr----------------- announced changes in committee mem bers for next year. All members are the same except for the follow ing ch a n g es. . .
I raced ahead to learn, perhaps, what doctor had acquired a new hairpiece or which specialist was beginning to put on weight. Alas, nothing so dra matic followed. New chairmen of continuing education had simply as sumed office and the old editor had stepped down. The changes were in the membership of the committees, not the members. Confronted with this kind of confusion, Twain observed, “The difference between the right word and the almost right word is the difference between lightning and the lightning bug.” Continuing my restless reading, I noted in a course announcement that: The clinician . . . has lectured worldwide and is one of the most sought-after clinician [sic] nationally and internationally. His col leagues consider him to be an era in orthodontics.
The clinician may have made epoch-making contributions to his field, but he could never become an era because an era is “.. .a system of chronolog ical notation, a date or an event, a historical period.” Dental writers should also remember that “imminent” is not another version of “eminent” and that “infer” is not a synonym for “imply.” Is it idle pedantry to condemn careless choice of words? In a recent spe cial communication to the Journal of the American M ed ica l Association, Robertson and Robertson point out that confusion over words is not only puzzling but also costly. Or deadly. Failure to comprehend key words has caused disastrous airplane crashes. But let us call upon the gentle bibliophile, Isaac Disraeli, to offer the final argument: Whatever is felicitously expressed risks being worse expressed: it is a wretched taste to be gratified with mediocrity when the excel lent lies before us.
Jay Weiss, DMD
Gnathology
Angle's occlusion and the cusp-fossa ideal of organic occlusion.39 He developed a system of measurement whereby the maximum number of cusp-fossa relationships could be established. He improved on Angle's occlusion by obtaining from 5 to 10 fossa relationships. This was an excellent attempt to meet cusp-fossa requirements in spite of the handicaps of tooth-size discrepancies. Cusp-fossa relations are always preferable to cusp-embrasure occlusion, but are not always achievable. This is when occlusal adjustment pro cedures become necessary or else all teeth will not be in contact and there will have to be diaste mas someplace.
O rth op ed ic g n a th o lo g y J a c k L. H o c k e l, D D S, e d 485 p a g e s w ith illu stra tio n s. In d e x . A p p e n d ix. $160. C hicago, Q u in te s se n c e P u b lish in g Co, Inc, 1983
The opening sentence of this book de scribes the removable Crozat appliance as “the basic cause and effect of orthopedic gnathology,” and it is Crozat therapy that is the book’s central theme. Because the editor states that “It is assumed that the reader has some fam iliarity w ith the Crozat appliance,” this book is not a monograph for the beginning practitio ner, but a reference manual for the sophis ticated clinician. However, the assumed level of reader sophistication signifi cantly varies throughout the book. Addi tionally, the editor uses the book to criticize traditional orthodontic conven tion, aligning gnathologists, orthopedic gnathologists, dental kinesiologists, cra n ial o s te o p a th s , n u tritio n is ts , and myofunctional therapists against conven tional university-trained orthodontists. If these vagaries are overcome, the reader can enjoy an otherwise solid text. For the benefit of the uninitiated, the first three chapters cover the jargon and tenets of orthopedic gnathology. The def inition of organic occlusion and the his tory of Crozat therapy are carefully de tailed; however, the presentation of the biologic basis of orthopedic change is less thorough. Under diagnosis and treatment planning, the Whip-mix articulator with properly mounted casts is neatly pre sented as the orthopedic gnathologist’s primary diagnostic tool, and the use of Pont’s index is emphasized. These points are further advanced in the chapter on craniom axillary symmetry. However, principles of treatment planning and ini tial appliance design and adjustment are summarized and assume prior knowl edge of the reader. This is also true of the chapter on Crozat mechanics. In contrast, several disciplines are pre-
The opinions and com m ents expressed by review ers are th eir ow n and do not represent the views of the Editor or of the A m erican Dental Association. Publishers of books and distributors of audiovisual m aterials and film s are invited to subm it new items for review in th is section. •Titles preceded by an asterisk are available from th e ADA library.
I an Organic Occlus
lieOcclusion, the Goal of Gnathology
teeth are present the closure stoppers prevent wear and possible separation of the front teeth. Secondly, the first stage of protrusive disclusion. the first millimeter out of centric, cannot be gained by the incisors if they are not within .001" of con tact due to excessive horizontal overlap (overjet) or the lack of overbite (Fig. 1-12a and b). In this in stance. when an orthopedic correction cannot be made, the contact of the mesial inclinesof the low er buccal cusps can disclude the mandible by detruding beneath the distal inclines of the upper mesial marginal ridge. As Stuart noted, the upper ridges "behave with their opponents as if they were small incisors."41Thelower first bicuspidcan protrude in a similar relationship to the upper cuspid (Fig. 1-13a and b) to assist the disclusion.
IV. Primary Marginal Ridge Contacts Six of the ten characteristics are related to upperto-lower tooth relations. Uniform centric contact and cusp-fossa relations have been dicussed. Numbers. IV. V. VI and VII are the remaining four. Figure 1-9a diagrammed the fit of a lower buccal cusp into an upper mesial fossa This is a sagittal plane projection. Please note the contact on the distal incline of the upper mesial marginal ridge against the mesial marginal ridge of the lower buc cal cusp. The distal marginal ridge of the upper lingual cusp has a similar contact with the mesial incline of the opposing distal marginal ridge. Stuart has labelled this type of contact a closure stopper becauseit resists theforward component of the arc of closure, first described by Stallard in 1923» (Fig. 1-10). Figure 1-11is a horizontal plane illustration of the
Fig. 1-13 Diagram of the first can be provided by marginal ridge cont A: Second bicuspids
closure stoppers. These contacts are so named because they are the first contacts of closure in a gnathological wax-up. There are more closure stoppers than are shown here because all distal inclinecontacts on the upper and all mesial incline contacts on the lower are closure stoppers. Each closure stopper is opposed by an equalizer to be described below. Twosignificant aspects of these contacts are noteworthy. If posterior teethare lost e splayed. When |
In a cusp-fossa occlusion every closure-stopper is coupled with a contact on the distal incline of a lower triangular ridge or the mesial incline of an upper triangular ridge. This contributes a mesiodistal stability to the occlusion. Figure 1-9a illus trates in the sagittal plane a lower buccal cusp and the two contacts it has with the upper marginal (closure-stopper) and triangular (equalizer) ridges. Every cusp has four ridges: a mesial marginal ridge, a distal marginal ridge, a triangular ridgeand a central ridge. Three out of these four ridges can contact an opposing cusp in cusp-fossa occlu sion. In restorative gnathology this tripodism is a goal because a tripod is the most stable system in mechanics. Inorthopedic gnathology this isalso a goal whenever possible. Shaw noted that "in unworn or little worn denti tions the total area of the maximum intermaxillary contact in occlusion does not normally exceed three or four square millimeters.'42 Since all ridges are rounded in all three dimensions, the cusps take on the form of a gothic pyramid.43Two rounded surfaces meet at a point, so the contacts will be small. If this type of tangency is obtained there will be a built-in adjustability to wear. The cusp tips will be preserved and the occlusion will 31
O rthopedic gnathology
sented from a more elementary perspec tive. Myofunctional therapy is presented in classic “cookbook” form for the busy practitioner. It is an excellent, wellillustrated reference source for the inter ested practitioner. The negative aspects of myofunctional therapy’s history are, unfortunately, simply dismissed as re sulting from the actions of “unqualified personnel with improper training.” The chapter on nutrition includes discussion of respiration and feeding practices that blend well with the anthropologic and physiologic material included. Despite definition of cephalometrics as a secondary, and perhaps useless, diag nostic tool, a lengthy presentation of basic cephalometric anatomy precedes a summary of the Sassouni and JarabakBjork analyses. Similarly, although the chapter on functional jaw orthopedics is well written and illustrated, it seems al most out of place because of its basic, in troductory type of presentation. How ever, it is the inclusion of these materials, and craniognathic im plications, that qualify this as a text on orthopedic g n ath o lo g y ra th e r th a n ju st C rozat therapy. Not unexpectedly, the strongest sec tions of the text are those directed at clini cal practice. The chapter on early arch developm ent provides both excellent
treatm ent rationale and illustration of clinical methodology. This is also true of the case history presentations. The chap ter on record-keeping and practice man agement is also well done, and could be used as a training manual for office per sonnel. Overall, this text provides a thorough review of the current status of a rapidly developing clinical discipline. It should be included in the reading of anyone en gaged in Crozat therapy. John G. Crawford, DDS, MS Dr. Crawford is form er director, division of growth and developm ent, U niversity of Illinois College of Dentistry; he is in the private p rac tice of p ed ia tric dentistry an d orthodontics, Oak Park, 111.
Prosthetic treatment R e a litie s o f d e n ta l th era p y — a d e ta ile d r e v ie w o f p er io d o n ta l p r o sth e tic treat m en t R o n a ld L . M o lo ff, D D S, a n d S te p h e n D. S tein , DDS 4 5 9 p a g e s w ith illu s tr a tio n s . I n d e x . $78. C hicago, Q u in te s se n c e P u b lish in g Co, Inc, 1982
Drs. Moloff and Stein have authored an excellent atlas format text reviewing JADA, Vol. 108, A pril 1984 ■ 649
P U B L IC A T IO N
R E V IE W S
periodontal prosthetic treatment. In the first chapter the authors present C om m en t “Basic concepts of periodontics,” while in the second chapter they deal with clin Basic Goals of Occlusion ical objectives and include some excel lent questions, for example, “why do den tists have such difficulty critically ob serving their own work?”. In the third chapter the authors explain and illustrate some advanced periodontal A book by Celenza and Nasedkin. Occlusion. The State o l the Art. reported on a meeting that brought together some o f the most renowned authorities in the field. It prosthetic cases involving the interplay becomes evident upon reading the book that all these men are perfectionists who execute their different concepts and techniques with similar precision. Though of numerous specialists (such as the peri there are differing opinions regarding condylar position and ideal occlusal designodontists, oral and maxillofacial sur some prefer a full gnathologic approach to reconstructive dentistry, others develop relatively flat occlusal patterns-all agree the operator m ust be able to guide the geons, fixed and removable prosthodon mandible into a reproducible position that consistently yields accurate records that can be transferred to an articulator. W hether the articulator be fu lly or semi-adjust tists, endodontists, and general practitio able is dependent upon the clinician and his concepts of occlusion, The actual un derstanding o f th e concept o f occlusion should not have anything to do with one's ners) in the treatment. This chapter, enti articulator. In Comment, p. 141. we describe the basic centric landmarks sought in o rder to tled “Team dentistry,” emphasizes the achieve a "functional" occlusion. The restoration of a single tooth o r small section is proper sequence of treatment involving dictated by th e existing jaw position and occlusion. This is only attempted if there are no signs o f periodontal pathology o r TMJ dysfunction. When the existing occlusion the various specialists, cooperation be has lost stability becauseofthedeform itiesof disease, recordsare taken to develop the occlusion in the position o f centric relation. Definition of this position varies with tween the various specialists, and the im the clinician and, although not scientifically proven, it is safe to say centric relation must be a reproducible position with th e condyles probably being in the m ost supe portant role of the patient in maintenance rior position o f the glenoid fossa. Once models are mounted in centric relation, the clinician can make accurate decisions regarding modification o f crown-to-root ra (home care) of the desired result. tio, incisal guidance and cuspal inclination. With the foregoing fundamentals estab Cases of posterior bite collapse, together with moderate to advanced periodontitis are accompanied by significant bone loss, mobility and flaring and extrusion of the lished, the authors cite in the fourth chap 168 ter some 24 case reports with hundreds of excellent black and white and color illus trations, and a descriptive text and com Realities of dental therapy ments in a lecture-slide format. The authors are to be complimented and the text is recommended not only to ADDITIONS TO THE LIBRARY graduate students in periodontics and T h e b o o k s lis te d h e r e h a v e b e e n r e c e n tly prosthodontics but to all dentists whose a d d e d to th e B u re a u co llectio n . R e q u e s ts f o r primary interest is in periodontal or pros- th is m a te ria l, a v a ila b le on lo a n to a ll m e m thodontic care, or both. b e rs o f th e A sso c ia tio n , s h o u ld b e a d d r e s s e d Charles H. Casey, DDS to th e B u re a u o f L ib r a r y S e rv ic e s . T h e re is n o Dr. Casey is professor of fixed prosthodon tics, departm ent of restorative dentistry, the University of Texas Health Science Center at Houston, Dental Branch, an d consultant in fixed prosthodontics, department of dental oncology, division of surgical services, M. D. A nderson Hospital and T um or Institute, H ous ton.
ANNOTATION T h e fo llo w in g a n n o ta tio n h a s b e e n p r e p a r e d b y A le th a A . K o w itz. T h e p u r p o s e o f th is a n n o ta tio n is to p r o v id e a n im m e d ia te , b rie f, d e sc rip tio n o f a n e w p u b lic a tio n .
C h ron ic p a in an d TMJ sy n d ro m e G e ra ld N. S m e r n o ff, D D S 12 p a g e s w ith illu stra tio n s. $4. B e th e sd a , M d, A r ie l E n te rp rise s, 1983
This small, attractive dental health edu cation pamphlet explains some of the fac tors relating to the complex problem that is the Temporomandibular Joint (TMJ) syndrome. Brief descriptions of possible symptoms are given as are descriptions of the anatomy of the joints and the anatomy of the human body relating to the syn drome. Diagnosis and possible therapies are briefly discussed with the caution that TMJ dysfunction is a problem best ad dressed by the trained professional. 650 ■ JADA, Vol. 108, A pril 1984
c h a rg e f o r b o rro w in g b o o ks, b u t th e r e is a s e r v ic e c h a rg e o f $10 f o r m e m b e r s , $15 f o r n o n m e m b e r s f o r e a c h p a c k a g e l ib r a r y . M e m b e r s o f th e A sso c ia tio n w h o w ish to p u r c h a se b o o k s m u s t e n c lo se a c h e c k o r m o n e y o r d e r w ith th e r e q u e s t. I llin o is r e s id e n ts s h o u ld a d d 7% re ta ile r s u se ta x to th e p u r c h a se p r ic e o f b o o k s. B o o k p r ic e s a re su b je c t to c h a n g e w ith o u t n o tic e in a c c o rd a n c e w ith c h a n g e in p u b lis h e r ’s p ric es, a n d b o o k s a re n o t r e tu r n a b le f o r c re d it. N e a r ly a ll th e d e n ta l jo u r n a ls p u b lis h e d in th e w o rld a t p r e s e n t a re a v a ila b le to m e m b e r s on lo a n . A lis t o f b o o k s, p a c k a g e lib r a r ie s , a n d jo u r n a ls is a v a ila b le on re q u e st.
Books Emergency p hysician’s guide to dental care. Berry, H.W., ed. Philadelphia, U niversity of Pennsylvania Press, 1983. 122 pp Factors an d m echanism s influencing bone growth: proceedings of the international conference held at the U niversity of Cali fornia Center for the H ealth Sciences, Los Angeles, Jan 5-7, 1982. Dixon, A.D., and Sarnat, B.G., eds. (Progress in clinical and biological research, vol 101). New York, Alan R. Liss, Inc, C1982. $97.57 Hill, C.M., and Morris, P.J. General anaesthesia and sedation in dentistry. (Dental practi tioner handbook, no. 32.) Bristol, John G. W right, 1983. 151 pp Hobsley, M. Color atlas of parotidectom y. (Surgical procedures, vol 1.) Oradell, NJ, M edical Economics Books, cl983. 96 pp. $29.06
In te rn a tio n a l C onference on M ono/luoro-
Comment
teeth (Fig. 4-176). This bone resorption and extrusion of the anterior teeth result in an unfavorable crown-to-root ratio. Mechanically, these teeth function at a deficit due to secondary occlusal trauma. O ur main objective is to shorten the teeth, thus creat ing a more favorable ratio. A s the anterior teeth are shortened, a decrease in the in cisal guidance is observed. This decrease means fe wer horizontal (excursive) forces transmitted through the teeth to th e periodontium(Fig. 4-177). By establishing a lingual platform with centric stops where necessary, forces are directed more ver tically through the long axis of the teeth. This can only be achieved after a more fa vorable crown-to-root ratio and decreased incisal guidance are accomplished. Quite often, orthodontic retraction o f the maxillary and mandibular anterior teeth is also necessary. 169
p h o sp h ate (1983: Boston). Monofluorophosphate perspectives: the com pound and its past, present, and future applica tion: proceedings of the International Con ference on M onofluorophosphate, Boston, June 9-10,1983. Gron, P., andE ricsson, Y., eds. (Caries research, vol 17, su p p l 1) Basel, Sw itzerland, S. Karger, 1983. 135 PP International Symposium on Ceramics (1st: 1982: New Orleans). Dental ceramics: pro ceedings of the First International Sym posium on Ceramics. McLean, J.W., ed. Chicago, Q uintessence Publishing Co, Inc, C1983. 541 pp. $143.08
Johnson, D.R., and Moore, W.J. Anatomy for
dental students. Oxford, Oxford Univer sity Press, 1983. 266 pp. $30.59 Kohn, H.B. Clinical applications of hypnosis: a m a n u a l fo r th e h e a lth p ro fe s s io n a l. Springfield, 111, Charles C Thomas, 1983. 135 pp Manson, J.D. An outline of periodontics. (Den tal practitioner handbook, no. 33.) Bristol, John G. Wright, 1983. 207 pp A p h y sician ’s guide to gearing up for retire m ent. A m erican M edical A ssociation. Chicago, American M edical Association, 1982. 1 vol (loose-leaf). $39.95 Textbook of oral and maxillofacial surgery, ed 6. Kruger, G.O., ed. St. Louis, C. V. Mosb Co, 1984. 782 pp. $42 Treatment of hemifacial m icrosom ia. Harvold, E.P.; Yargervik, K.; an d Chierici, G., eds.
PU B L IC A T IO N
REVIEW S
N ew York, Alan R. Liss, C1983. 247 pp. $49.37 Weiser, R.S., and Myrvik, Q.N. Fundamentals of im munology, ed 2. Philadelphia, Lea & Febiger, 1984. 510 pp Yellow pages: a professional advertiser’s guide to maximum impact yellow pages adver tising. Phoenix, The Advertising Dentist, TAD Enterprises, 1983. 58 pp. $25
Periodicals AADC Beacon, American Association of Den tal Consultants, Baltimore AGD Dentistry —in general! Iowa City Akyurt Saglik Ocagi Bulteni, Ankara, Turkey B oston U n ive rsity M edical Center, Centerscope, Concord, Mass CD: Career Directions for Dental Kygienists, Holmdel, NJ California D ental Laboratory Association (South) Communicator, Los Angeles Cleveland Dental Society Bulletin, Cleveland (formerly: The Bulletin of the Cleveland
Dental Society) The Coit Tower, Northern California State Den tal Hygienists Association, San Francisco (formerly: San Francisco Component) College of Dental Surgeons of Saskatchewan Newsletter, Saskatchewan, Canada Concept 80’s, Missouri Academy of General Dentistry
Curette Courier: Newsletter of the Pinellas County Dental Hygienists’ Society, Palm Harbor, Calif The DDS’ Alert, Tulsa, Okla The Dallas Dental News, Dallas County Dental Assistants Society, Irving, Tex Dayton Dentistry, Dayton, Ohio (formerly: The
Dayton Dental Society Bulletin) Dental Medicine, Journal of the Israel Dental Association, Tel Aviv Dental Society of Waukesha County Newslet ter, Delafield, Wis (formerly: Waukesha County Society Newsletter) Dentist/investor, Fairbum, Ga Detroit Dental Clinic Club Newsletter, Dear born, Mich The Family Dentist, Ohio Academy of General Dentistry, Toledo, Ohio Floss flyer: ASDHA Newsletter, Alaska State Dental Hygienists’ Association, Anchor age, Alaska Focus on Dental Computers, Cherry Hill, NJ Forum o f Esthetic Dentistry, Chicago GP News, Southern California Academy of General Dentistry, Santa Monica (for merly: Southern California Academ y of General Dentistry, GP News) Ka Leo, Hawaii Dental Hygienists’ Association, Aiea, Hawaii (formerly: HDHA: Hawaii
Dental Hygienists’ Association) MCDS Journal, Multnomah County Dental So ciety, Portland, Ore (formerly: MCDS bul letin} NCODS Articulator, North Central Ohio Dental Society NCSDHA P eninsula Component, Northern California State Dental Hygienists’ Asso ciation News Line/University o f Michigan, School of Dentistry, Ann Arbor The North Carolina Dental Review, Chapel Hill, NC The Review of A kyurt Health Centre Bulletin, Ankara, Turkey Trends and Techniques in the Contemporary Dental Laboratory, Alexandria, Va 652 ■ JADA, Vol. 108, April 1984
Dentalese I t ’s here. 1984. George Orwell predicted that by now a triumphant tyranny would have completed its debasement of the English language. Orwell had watched the process with dismay, writing: Defenseless villages are bombarded from the air, the inhabitants driven out into the countryside, the cattle machine-gunned, the huts set on fire with incendiary bullets: this is called pacification.
Orwell treasured precise words. He believed they have not only the power to explain, to persuade, and to delight, but also the power to corrupt, to control, and to enslave. Remember, the final victory of Big Brother would have been achieved when everyone believed the three slogans of the Party: WAR IS PEACE FREEDOM IS SLAVERY IGNORANCE IS STRENGTH
Similarly, Graves and Hodge, in The Reader over Your Shoulder, argued: No writer of English can be sure of using exactly the right words even in a single context, and even after 20 or 30 years of selfeducation. But he should at least act on the assumption that there is always an exactly right word, or combination of words, for his purpose—which he w ill gratefully recognize as such if it happens to occur to him; and that though he may not always find the right word, he can at least learn . . . to avoid the quite wrong ones. And even the not quite wrong.
Mark Twain thought the effect of an “intensely” right word was electrify ing in a physical and even spiritual way. When we allow ourselves to select the “quite wrong word,” the effect is dismal. Recently, in a bulletin of a county dental society, I was astonished to read: Pres. Elect, Dr----------------- announced changes in committee mem bers for next year. All members are the same except for the follow ing ch a n g es. . .
I raced ahead to learn, perhaps, what doctor had acquired a new hairpiece or which specialist was beginning to put on weight. Alas, nothing so dra matic followed. New chairmen of continuing education had simply as sumed office and the old editor had stepped down. The changes were in the membership of the committees, not the members. Confronted with this kind of confusion, Twain observed, “The difference between the right word and the almost right word is the difference between lightning and the lightning bug.” Continuing my restless reading, I noted in a course announcement that: The clinician . . . has lectured worldwide and is one of the most sought-after clinician [sic] nationally and internationally. His col leagues consider him to be an era in orthodontics.
The clinician may have made epoch-making contributions to his field, but he could never become an era because an era is “.. .a system of chronolog ical notation, a date or an event, a historical period.” Dental writers should also remember that “imminent” is not another version of “eminent” and that “infer” is not a synonym for “imply.” Is it idle pedantry to condemn careless choice of words? In a recent spe cial communication to the Journal of the American M ed ica l Association, Robertson and Robertson point out that confusion over words is not only puzzling but also costly. Or deadly. Failure to comprehend key words has caused disastrous airplane crashes. But let us call upon the gentle bibliophile, Isaac Disraeli, to offer the final argument: Whatever is felicitously expressed risks being worse expressed: it is a wretched taste to be gratified with mediocrity when the excel lent lies before us.
Jay Weiss, DMD