Review of Dental Research

ORIGINAL ARTICLES

Since 1955, the Council on Dental Research each year has presented a review of research develop­ ments in selected areas o f interest to dentistry. The pattern for these reports was modified in 1965 so that most topics could be repeated every third year. Two categories of review articles de­ viate from the schedule. First, because of current interest, a review of research in clinical dentistry is included each year. Second, the “Special” cate­ gory provides an opportunity to consider topics that are more specialized but probably will not be repeated in 3 years. The topics covered in this issue are biochemis­ try, clinical dentistry, anatomy, radiation biology, epidemiology, and dental caries. The Council is considering a new format for the presentation of research information. The Council is grateful to Parker E. Mahan, chairm an of the Council on Dental Research, who served as editor for these reviews. The Council is also grateful to John C. Greene, F rank J. Sobkowski, Andrew D. Dixon, Robert L. Glass, R obert Van Reen, and Paul H. Keyes for preparing reviews in their respective special­ ties for the 1968 reviews o f dental research.

REVIEW OF DENTAL RESEARCH

Research in anatomy

Andrew D. Dixon, MDS, PhD, DSc

Electron microscopy and histochem ical technics have been used to solve some of the problems of dental tissue structure such as tooth and orofacial development and bone and facial growth.

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Research on the anatomy of the orofacial region has continued to increase during recent years. The technics of anatomical investigation, namely, gross dissection and light microscopy, continue to be supplemented by more contemporary micro­ scopic methods that make extensive use of ultra­ violet, interference, and polarizing equipment. Rapid advances made in the technics of electron microscopy and the electron microprobe, are also included in this review of current trends in ana­ tomical research. A number of histochemical technics used to de­ tect the presence of chemical compounds in bi­ ological tissues have been modified for use at the fme-structure level, and considerable advances in our knowledge of dental tissues are being made. These technics and the others which are re­ ferred to in this review emphasize the close rela­ tionship of anatomical research to parallel bio­ chemical and physiological investigations, and al­ though the emphasis in this paper is on the struc­ tural details, the interdisciplinary trend in biolog­ ical research must not be overlooked. The subjects covered in this review were sub­ divided into the dental tissues, including enamel,

dentin, and pulp; tooth development; the peri­ odontal ligament; the oral mucous membrane; innervation; the salivary glands; orofacial devel­ opment; bone and facial growth; and the man­ dibular joint.

plaque formation were shown in electron m icro­ graphs by Frank and Brendel.37 The enamel mem­ brane was studied at different âges,38 39 and re­ cently, Hay40 has shown that sialoproteins are responsible for the early stages o f formation o f the acquired enamel pellicle.

Enamel Dentin A wide variety of methods have been used to study enamel structure, including phase contrast and interference microscopy, X-ray spectrography, and microradiography.1-7 Electron microscopy technics have been used extensively. Travis and Glimcher8 studied the ori­ entation of enamel crystals, and Glas and Nylen9 found that the rod sheaths were almost entirely devoid of mineral matter. Meckel and others10 could find no evidence of an interprismatic sub­ stance, and the problems o f electron microscopy of enamel were detailed by Hinrichsen and E n­ gel.11 Gwinnett12 13 used the technic to confirm the presence o f a prismless zone. Electron-probe microanalysis technics14 have been used to determine the increased concentra­ tion of calcium and phosphorus from the dentinoenamel junction toward the surface.15 16 Data ac­ cumulated by means of a microprobe by Johnson and Singer17 showed an inverse relationship be­ tween strontium and calcium, and Frazier18 re­ lated fluoride content of enamel to duration o f ex­ posure. There has been much interest with regard to the nature o f the bands of Schreger.19-22 An in­ teresting study by Osborn23 suggested that the variations in thickness within sections accounted for their appearance in microradiographs, although opinions differ as to whether these bands can be shown by use of microradiography.24 25 The uptake of various substances by enamel has been studied extensively by means of autora­ diography,26 27 neutron activation analysis,28 and X-ray diffraction.29 Deciduous teeth analyzed af­ ter they were exposed to radium30 showed that the concentration was relatively greater in the enamel. An initially high level of fluoride after teeth were treated with stannous fluoride solu­ tions confirmed that the uptake was by diffusion with simultaneous chemical reaction.31-33 Confusion regarding the nomenclature and the nature of the dental cuticle was reviewed by Hodson,34 who proposed its hematogenous origin.35 A fluorescent antibody technic was used to ex­ amine enamel deposits,36 and the first stages of

Investigations of the properties,41 structure, and formation of dentin include studies of interglobular dentin.42 43 Stevenson44 saw fluid droplets exuded from dentinal tubules subjected to a re­ duced pressure in vitro. T hat acid mucopolysac­ charide is an im portant prerequisite for m inerali­ zation was shown by means of light and electron microscopy,45 M atena46 gave a detailed descrip­ tion of dentinogenesis, and intact dental pulp transplanted subcutaneously showed that odonto­ blasts could produce bone.47 Osborn48 used a geo­ metric method to demonstrate that secondary cur­ vatures may be produced by a buckling of the odontoblast processes in predentin. Ten Cate49 showed the alkaline phosphatase activity in odon­ toblasts which increased with further cell differ­ entiation. Takum a and E da50 showed the presence of the peritubular matrix in root dentin from its formative stage. With respect to age, Philippas and Applebaum 51 52 studied secondary dentin formation, and Stanley and others53 the rate of reparative dentin formation. The intensity of the staining of dentin decreases considerably through the third decade,54 and the uptake of radioactive phosphor­ us was less in translucent dentin com pared with that of normal m atrix.55 M jor56 described four zones of staining reaction in coronal dentin. Yaeger57 found that strontium and fluoride inhib­ ited primary m ineralization of predentin, and the average fluoride concentration reached a max­ imum value at an age which depended on the type of tooth.58 By means o f microradiography, the histologic structure of dentin was correlated with its mineral content.59 60 Measurements of hardness were sig­ nificantly lower close to the sites o f resorption;61 therefore, the testing o f operative procedures and filling materials perhaps should include detailed studies of the dentin.62 The m ineralization of den­ tin was studied by use o f a variety o f technics,63 64 and the hypermineralization of the peritubular matrix was confirmed by use of the electron m i­ croprobe.65 Dixon: RESEARCH IN ANATOMY ■ 1329

The electron microscope has been used to show the collagenous nature of the Von Korff fibers.66 A periodontoblastic space exists in human den­ tin,67 and cytoplasmic organelles were demon­ strated in the odontoblastic processes,68 which suggested considerable metabolic activity. Intertubular m atrix fibers obliterated dentinal tubules in adults over 30 years of age,69 and a hydrody­ namic mechanism for dentin sensitivity received support.70 71 Ishihara72 showed nerve fibers in the dentinal tubules beyond the dentin-predentin junc­ tion.

Pulp T he vascular pattern of the dental pulp was studied by means of histologic,73 photoconductive,74 and electron microscopy technics.75 Neither blood pressure nor cellular proliferation appears to af­ fect the process of tooth eruption directly.76 Coady and others77 found no effect on tooth eruption from gamma-radiation. Bernick78-80 gave a de­ tailed description o f the terminal relationship be­ tween vessels and nerves in the pulp, which de­ pended on the region in which they were located and their age. Wounds o f the dental pulp were in­ vestigated,81 82 and Dixon and Peach83 used den­ tal polyps to study migratory and synthesizing fi­ broblasts. Other electron microscopy studies have dealt with the differentiation of fibroblasts in the in­ cisor pulp.84 85 The fine structure of pulpal cells was similar to that found in the same types of cells in other organs.86 Pincus87 described a mem­ brane between the body of the pulp and the odon­ toblasts yvhich may be important in ion transfer. The importance of plasma and mast cells in the continuous defense of the healthy pulp was sup­ ported by electron microscopy studies.88 Human dental nerves are ultrastructurally similar to those observed in other tissues,89 and the absence of the perineurium was noted,90 with emphasis placed on its function as a diffusion barrier. The pulp has been subjected to tissue culture technics by Pom erat and Contino.91 Cell prolifera­ tion has been quantitated by Chiba92 and studied autoradiographically by Robins.93 As the volume of the pulp was reduced, a slight relative increase in cell population was observed.94 95 Histochemi­ cal approaches have been used to examine the ac­ tivities o f various enzymes.96-98 Two types of fi­ broblasts have been identified by use of electron 1330 ■ JADA, Vol. 76, June 1968

microscopy.99 100 Han and others101 described three stages in fibroblast differentiation, and Mjor and Shackelford102 evaluated human pulp tissue by use of X-ray absorption methods. Apparently, changes in pulp citrate concentration are not cru­ cial in producing or controlling changes in min­ eralization.103

Tooth development Significant advances in dental embryology were reviewed.104 Tissue culture technics and transfilter interaction showed the sequence of changes during cellular differentiation105 106 and morphodifferentiation in vitro.107 C hiba108 T bund that mitotic activity in the internal enamel epithelium was greatest in young rats, and Gaunt109 investi­ gated the rate of tooth development. Studies of cell height and nuclear volume by Costacurta110 indicated that the stellate reticulum and stratum intermedium are responsible for the promotion of m atrix calcification. Kallenbach and others111 in­ vestigated the role o f the cell web of the ameloblast for rigidity and resistance to stress. Mitotic activity within the dental organ was studied by means of autoradiography,112 and Chiba and others113 investigated the rate and duration of cell division in the internal enamel epithelium. Several studies114-117 in which the electron mi­ croscope was used have added to our knowledge about the enamel organ. The nature of preenamel was compared at the light and electron micro­ scope level by R eith.118 Histochemical investigations included studies of the incorporation of tetracycline.119 120 Goren and G erstner121 determined the sites of location of radioactive calcium in fetal oral tissues and newly formed dentin and enamel. Labeled com­ pounds correlated the migration rate of ameloblasts with the eruption rate of teeth.122 The lipid content o f human odontoblasts was demonstrated by Stewart and others,123 and Thonard124 used X-ray effects to show the radiosensitivity o f odon­ toblasts. Autoradiographs of the preameloblast zone showed a surplus of deoxyribonucleic acid.125 126 A variety of histochemical technics characterized amino groups,127 and Katchburian and others128 related lysosomes to the secretory processes of dental tissue formation. The carbohy­ drate content of the odontoblast indicated a dual origin of the dentin ground substance,129 and one o f the activities of the transporting type of ameloblast is to remove sulfur compounds from

the enamel during its m aturation.130 M ineralization of developing enamel has been studied by use o f electron optical and X-ray dif­ fraction technics,131 m icroradiography,132 and, more recently, the scanning electron-probe X-ray microanalyzer.133

Periodontal ligament Studies of the normal structure o f the ligament at the light and electron microscope level have con­ tinued, and important studies have involved histo­ chemical technics. Zwarych and Quigley134 dis­ cussed the intermediate plexus. Results o f routine histologic methods135 suggested that the hammock ligament performs a supporting function only, and the differences between the vascular arrangement in the periodontal membrane and the gingiva were used to emphasize the nutritional roles o f the two structures.136 137 O f the few accounts o f cementum ,138 electron micrographs showed that uncalci­ fied fibrous struptures which are seen in dried ground sections and in m icroradiographs repre­ sent only the uncalcified cores of Sharpey’s fibers. Studies of the fine structure of the developing perio< ontium139 drew attention to the presence of synthesizing fibroblasts, collagen fibrils, ground substance, and occasional oxytalan fibrils. T etra­ cycline labeling and polychrome stains were used to trace the adjustments involved in tooth move­ ments,140 and distinct differences were seen in fibrous attachments in regions of bone deposition or resorption. Glycolysis in epithelial rests o f Malassez was demonstrated.141 Carneiro and de M oraes142 were able to show a constant renewal of periodontal collagen by means of radioautography and made the important observation that the rate of collagen formation exceeds that in dense connective tissue elsewhere. Further evidence was provided that oxytalan fibers are a distinct connective tissue type related to elastic fibers.143 The relative activities of the various enzymes were characterized by Todo and M ori.144 Osteoclasts were formed in the peri­ odontium by the fusion of loose connective tissue cells.145 146 The periodontium of shortened, and hence fast­ er growing, teeth is no different from that of nor­ mal dentition.147 Cohn,148 149 however, found a remarkable and progressive atrophy of the peri­ odontium after loss of function. Experimentally in­ duced changes in the periapical tissues were simi­ lar to those seen in children.150

Oral mucous membrane Much attention has been given in recent years to the fine structure and histochemistry o f the oral mucous membrane, which includes the mecha­ nism of keratinization and the epithelial attach­ m ent.151-157 The distribution of elastic tissue in the oral mucosa was investigated,158 and the rec­ ognition of gingival reticulin159 160 as well as the nature o f the basal lam ina161 has been studied ex­ tensively. The relationship of the basal lam ina to epithelium or connective tissue continues to be a subject of controversy and has been studied in some detail by Stem .162 A generation cycle o f 96 hours for the cells o f the palate and dorsal surface of the tongue was determ ined.163 Bowman and Latham 164 related the fiber-free median region o f the palate to develop­ mental epithelial remnants and a poor blood sup­ ply, whereas cultured cells from the palatal m u­ cosa were studied for intracellular features o f the epithelial cells.165 In addition to the more routine methods of study of the gingivodental barrier,166 estrogen ther­ apy exaggerated features o f normal development of the epithelial attachment because o f increased aging and vascularity.167 Im portant electron mi­ croscopy investigations of the gingivodental junc­ tion have led toward a more complete understand­ ing of the nature of the junctional complex.168 169 Histochemical studies of the oral epithelium in­ cluded phases o f keratinization;170 technics for measuring the enzyme activity in the gingiva,171 a tissue culture,172 and protein biosynthesis;173 and electron chemical technics.174 No changes were seen by Smith and Cimasoni175 in the distribution of cholinesterases during local anesthesia, which was in agreement with other reports since non­ specific cholinesterases were seen particularly at the sites o f sensory end organs.

Innervation Although there have been a number of studies at the gross anatomical level, most investigations have involved histologic procedures and, more recently, electron microscopy. M urphy and Thom ­ son176 found evidence for the doctrine of neural patterns as a postulate o f afferent neural organiza­ tion. Alexander and Fitzgerald177 showed the first example of transmedian neuromuscular innerva­ tion. M ucocutaneous end organs were surveyed Dixon: RESEARCH IN ANATOMY ■ 1331

by Tolman and others,178 and perception thresh­ olds in teeth demonstrated effectively that the character o f sensation cannot be taken as a guide to the, pulp condition.179 The absence of cholinesterase activity in odontoblast cells made the role of the odontoblast in dentin sensitivity doubt­ ful,180 and the section o f the nerve supply to low­ er incisors had no effect on the eruption rate.181 A surprisingly rich innervation existed in chronic inflammatory periapical lesions.182 Neurohistological technics were used in sev­ eral studies which dealt with the nerve supply to muscle and the oral mucosa.183-185 Elaborate de­ scriptions of the neurohistology of the tongues of several mammals were given.186 187 The electron microscope was used by several authors to study taste bud structure,188-190 and a number of cell types were presumed to represent different func­ tional states of the gustatory cells.191 The central connections of the afferent fibers of the trigeminal nerve were studied by Brown192 and presented in a detailed review by Rhoton and others.193 Johnston194 has studied the migration and fate of cranioneural fold cells by means of radioautographic methods, whereas Hum phrey195 showed that maxillomandibular fibers of the tri­ geminal nerve reached the basal lamina of the oral epithelium earlier than those which supplied the cutaneous epithelium around the mouth. T ri­ geminal ganglia have been maintained in tissue culture and new features dem onstrated.196 Hen­ derson197 dealt with the procedures for the relief of trigeminal neuralgia, and recently, reports have appeared on the fine structure of human trigeminal ganglia.198

Salivary glands Rodent salivary glands continue to be used ex­ tensively in studies of structure and function. In­ vestigators using histochemical and electron mi­ croscope methods disagreed on the nature of myo­ epithelial cells and their secretory role.199 200 An interesting paper201 described sex differences in the duct components, and signs of secretion by the intercalated ducts were seen by the 14th day.202 Elaborate chemical procedures have helped to resolve some problems of salivary gland function, with respect to monoamine oxidase activity,203 the presence of a sialoprotein,204 and DNA metab­ olism.205 206 Caldwell and Shackleford207 con­ ducted a chemical, immunological, and electron microscopy study of centrifuged human saliva. Studies of abnormal salivary gland function208 209 1332 ■ JADA, Vol. 76, June 1968

included the observation that the obstruction of salivary ducts produces atrophic changes within three days. Alterations in mastication210 failed to show any significant relationships to the periodon­ tal syndrome. Travill211 reported masculinization of the submandibular glands during pregnancy, and changes in the salivary tissue followed the im­ pairm ent of the thyroid function.212 After isopro­ terenol, ultrastructural alterations in gland struc­ ture were correlated with physiological and bio­ chemical information.213 Nerve tissue development in the submandibular ganglia214 and the role o f the submandibular gland in the synthesis or storage of nerve growth factor were discussed.215 Otic ganglion cells were char­ acterized by means of the electron microscope,216 and a double innervation of the parotid gland was demonstrated.217 Denervation resulted in a weight loss in the glandular m aterial.218

Orofacial development The technics of cephalometrics have been applied to human fetuses. Statistical analysis o f linear and angular measurements of the facial complex has determined distinct patterns of growth.219 Subse­ quently, Burdi and Lillie220 determined m orpho­ logical changes in the maxillary dental arch dur­ ing fetal development and compared its shape to a catenary curve, first recognized at age 9.5 weeks o f the fetus. The development of the palate continues to be investigated.221-223 Chaudhry and others224 and Jacobs225 compared the effects of cortisone, tha­ lidomide, and vitamin A on palate formation, when it was noted that thalidomide did not pro­ duce clefts in doses in excess of those of cortisone levels. Coleman226 found closure of the palate in normal fetuses to begin in the anterior third of the mouth, achieved by rotation of the palatine processes. M ore caudally, palate closure resulted from the fusion of outgrowths from the medial sur­ faces of the palatine processes, and their narrow width in clefts of the palate suggested a suppres­ sion of their growth at a critical stage. Statistically, genetic transmission accounts for only about a fifth of the total number of cleft palates.227 Changes in fetal posture because of alterations in the vol­ ume of amniotic fluid were shown to be an im por­ tant causal mechanism, and the dentition can be affected by the same etiological factors that cause orofacial clefts.228 The usefulness of tissue culture technics was emphasized229 230 and Chan and others231 evaluated 60 palatal transplants histo­

logically. Cell proliferation in epithelial remnants of the midline area were thought to explain the presence o f epithelial pearls, although it was sug­ gested that the association with developmental cysts needed further clarification.232

Bone and facial growth Studies of bone structure have used the technics of chemistry and X-ray diffraction233 234 to ana­ lyze the crystal chemistry of hydroxyapatite in teeth and bones. Crystallinity values235 were shown to be correlated with changes in fluoride content, which can be tolerated without producing significant physiological consequences. Tetracyclines have continued to be used in studies of bone growth236 237 as well as in other bone markers, such as lead acetate.238 Goldhaber239 found that calcification in tissue culture was lim it­ ed to certain portions o f osteoid collagen, which indicated the presence o f a calcification inhibitor factor. An investigation of the effects of a para­ thyroid extract on thei calvaria in tissue culture supported the concept that there is a relationship between osteoclasts, acid phosphatase, and bone resorption.240 The fate of dentin implants and osteogenic effects were studied.241-243 A t the more gross anatomical level, the vascular pattern of the mandible has been studied by microangiogra­ p h y .

244 245

A number of investigators have studied facial growth patterns under normal and experimental conditions.246 Cleall247 showed that strong expan­ sion forces on the m idpalatal suture in the mon­ key increased the width o f the maxillary arch by disrupting the midpalatal suture. Various remod­ eling movements o f the growing maxilla con­ tributed to the drifting of human teeth.248 Bjork249 perfected technics for inserting metallic implants in the upper jaw and analyzed the direction of sutural growth. Regional growth movements were the subject of cephalometric studies.250-252 Changes in dental base relationships three to four months after teeth are extracted can be attributed to a change in m andibular posture or muscle attach­ ments.253 254 Experimental studies of face and jaw growth have continued. Sarnat and Wexler255 de­ termined that resection of varying amounts of the nasal septum in rabbits resulted in ,a shortening o f the snout with a consequent abnormal position of the upper incisors. A temporary masticatory im­ balance was noted by Sprinz256 after division of the neck of the mandible.

Mandibular joint A considerable num ber of studies on the structure, development, and function of the tem porom andib­ ular joint have been conducted in recent years.257260 An interesting study by Parsons and Boucher261 showed that the lack of erectile properties of the meniscus suggested that it does not have a signifi­ cant role in limiting retrusion of the mandible. Three cell zones with distinct functions for cellu­ lar remodeling of the articular surface were shown by the use of tritiated compounds.262 263 Development o f the m andibular joint was the subject of study by From m er,264 and Symons265 has investigated the secondary cartilage o f the m an­ dibular condyle using histochemical technics. The central part of the disk and articular surfaces con­ tains no elastic fibers266 267 and findings on joint structure from rodents have dubious applicability to human m aterial.268 Free nerve endings in the joint may subserve other modalities besides pain269 and may contribute to the production of various clinical entities.270 M any o f these features for the human joint were reviewed by M offett,271 and various stages in the development and ossification of joint components were described.272 273 The mandibular joint has been the subject of many experimental investigations— in the ab­ sence of the condylar growth center,274 after uni­ lateral loss of teeth,275 and in regard to a condylectomy.276 Removal of all or part of the condyle results in retardation of growth of the mandible,277 and Hayes278 showed regeneration was from the chondrogenic layer. Schneider and M eyer279 released m andibular molars from occlusal contact and found that the height of the mandible and tooth position were not mediated by events at the condyle. An interesting study280 provided evi­ dence that changes in the condyle during scurvy and healing are consistent with its role as a re­ modeling center. No significant changes in the joint followed loss of all teeth during a ten-year observation period.281

Summary Contemporary anatomical research implies that highly sophisticated instrumentation and technics are used to try to solve some o f the problem s of dental tissue structure. Electron microscopy tech­ nics have been applied extensively. O ur knowl­ edge of the distribution of fluoride in teeth has Dixon: RESEARCH IN ANATOMY ■ 1333

advanced. T he vascular pattern of and the effects o f age on the dental pulp have been thoroughly investigated, and the development o f the tooth is better under­ stood from the results o f studies which use electron microscopy and histochemistry. The precise na­ ture of dentin innervation remains unsolved. Studies of fine structure have extended to the periodontium where the rate o f collagen form a­ tion exceeds that in other connective tissues. Keratinization is more clearly understood, and at­ tem pts are being made to understand structural features throughout the trigeminal pathway. Studies of facial growth now include fetal cephalometrics and technics of metallic implant in humans, and the role of the mandibular joint region has been clarified. Doctor Dixon is assistant dean for research, director of th e D ental Research Center, professor o f dental science, School o f Dentistry, and professor o f anatom y, School of M edicine, U niversity of North Carolina, Chapel H ill. 1. G w innett, A.J. Histology of norm al enam el. III. Phase contrast study. J Dent Res 4 5 :8 6 5 , 1966. 2. Coklica, V., and Brudevold, F. Density fraction s in hu­ m an enam el. Arch Oral Biol 11:12, 1261, 1966. 3. W eidm ann, S.M.; W eatherell, J.A., and Ham m , S.M. Variations o f enam el density in sections o f hum an teeth. Arch Oral Biol 12:1, 8 5 , 1967. 4 . Calonius, P.E.B., and Visapaa, A. The inorganic con­ stitu e n ts o f hum an teeth and bone exam ined by X-ray em is­ sion spectrography. Arch Oral Biol 10:9, 1965. 5. Angmar, B. Studies on the u ltrastructure o f enam el. V II. M icroradiographic and polarization m icroscopic study on developing hum an enam el. Odont Rev 16 :167 , 1965. 6 . Ripa, L.W.j G w innett, A.J., and Buonocore, M.G. The “ prism less” outer layer o f deciduous and perm an ent enam ­ el. Arch Oral Biol 11:1, 4 1 , 1966. 7. H offm an, R., and Gross, L. M icro structures o f dental enam el observed w ith th e d ifferen tial in terferen ce reflected lig ht m icroscope. N atu re 2 1 2 :5 0 6 6 , 9 9 2 , 1966. 8 . Travis, D.F., and Glim cher, M.J. Th e stru ctu re and organization o f and th e relationship between th e organic m atrix and th e inorganic crystals o f em bryonic bovine enam ­ el. J Cell Biol 2 3 :4 4 7 , 1964. 9 . Glas, J.-E., and Nylen, M .U . A correlated electron m i­ croscopic and m icroradiographic study of human enam el. Arch Oral Biol 10:6, 89 3, 1965. 10. M eckel, A.H.; G riebstein, W.J., and N eal, R.J. S truc­ tu re o f m atu re human dental enam el as observed by electron microscopy. Arch Oral Biol 10:5, 77 5, 1965. 11. H inrichsen, C.F.L., and Engel, M .B. Fine structure of pa rtially dem in eralized enam el. Arch Oral Biol 11:1, 65, 1966. 12. G w innett, A.J. The ultrastructure of th e “ prism less” enam el of deciduous teeth . Arch Oral Biol 11:11, 1 1 0 9 ,1 9 6 6 . 13. G w innett, A.J. The ultrastructure of th e “ prismless" enam el of perm anent human teeth. Arch Oral Biol 12:381, 1967. 14. Frazier, P.D.; Little, M .F., and Casciani, F.S. X-ray d iffractio n analysis of hum an enamel containin g d ifferen t am ounts of flu oride. Arch Oral Biol 12:1, 35, 1967. 15. Sorem ark, R., and Qrfin, P. C hloride distribu tion in hum an dental enam el as determ ined by electron probe m i­ croanalysis. Arch Oral Biol 11:9, 8 6 1 , 1966.

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16. Frank, R.M.; C ap itan t, M ., and Goni, J. Electron probe studies of hum an enam el. J D ent Res 4 5 :6 7 2 , 1966. 17. Johnson, A.R., and Singer, L. An electron m icroprobe study o f rat incisor te eth with low or high concentrations of strontium . Arch Oral Biol 12:3, 3 8 9 , 1967. 18. Frazier, P.D. Electron probe analysis of hum an teeth. C a/P ratios in in cip ie n t carious lesions. Arch Oral Biol 12:1, 25,. 1967. 19. W eber, D. Phase m icroscopic observations o f rat in­ cisor enam el. Amer J A nat 11 7 :2 3 3 , 1965. 20. Rom aniuk, K., and Shroff, F.R. Th e relationship o f di­ rectional variation in term inal portions o f enam el rods to th e ir cross sectional appearance. New Zeal Dent J 61 :9 4 , 1965. 21. Lester, K.S. V ariab ility o f th e bands o f Schreger. Aust Dent J 10:217, 1965. 22. Lester, K.S. Th e bands o f Schreger: th e role of re­ flexion. Arch Oral Biol 10 :361 , 1965. 23. Osborn, J.W. Th e nature o f th e H unter-Schreger bands in enam el. Arch Oral Biol 10:6, 9 2 9 , 1965. 24. Gwinnett, A.J. Histology of normal enam el. IV. M icro­ radiographic study. J D ent Res 4 5 :8 7 0 , 1966. 25. Sundstrom , B. Schreger bands and th e ir appearance in m icroradiographs of human dental enam el. Acta Odont Scand 24 :2, 179, 1966. 26. Elwood, W .K. Th e distribution of 60Mn in th e enamel and dentine of th e rat incisor. Arch Oral Biol 10:4, 65 5, 1965. 27. Cotton, W .R., and H efferren, S.M. An autoradiographic study o f tryp top han e-H 3 incorporation into rat enam el and d e n tin e m atrices. Arch Oral Biol 11 :102 7, 1966. 28. Nixon, G.S.; Livingston, H.D ., and S m ith, G. Estim a­ tion of m anganese in human enam el by activation analysis. Arch Oral Biol 11:2, 2 4 7 , 1966. 29. Johnson, A.R. X-ray diffraction patterns o f rat incisor tooth enam el w ith a low or high strontium content. J Dent Res (suppl) 4 6 :7 9 , 1967. 30. Sam uels, L.D. U ptake o f radiu m -226 from drinking w ater into human deciduous teeth . Arch Oral Biol 11:6, 581, 1966. 31. M ellberg, J.R.; Laakso, P.V., and Nicholson, C.R. T h e acquisition and loss o f flu oride by topically fluoridated human tooth enam el. Arch Oral Biol 11:12, 1213, 1966. 32. Richardson, B. Fixation o f to pically applied flu oride in enam el. J Dent Res 4 6 :8 7 , 1967. 33. Duckworth, R., and Braden, M. The uptake and re­ lease o f flu o rin e -18 by human in tact surface enam el in vitro. Arch Oral Biol 12:2, 2 1 7 , 1967. 34. Hodson, J.J. A critic al review of th e dental cu ticle with special reference to recent investigations. In t D ent J 16:350, 1966. 35. Hodson, J.J. Origin and nature of th e cu ticu la dentis. N atu re 2 0 9 :5 0 2 7 , 9 9 0 , 1966. 36. Kramer, I.R .H ., and Ram anathan, K. Th e investigation of deposits on th e surface of human enam el by m eans of a fluorescent antibody technique. Arch Oral Biol 11:10, 1047, 1966. 37. Frank, R .M ., and Brendel, A. U ltrastru ctu re of the approximal dental plaque and th e underlying norm al and carious enam el. Arch Oral Biol 11:9, 88 3, 1966. 38. Leach, S.A., and Saxton, C.A. An electron m icroscopic study of the acquired p e llicle and plaque form ed on the enam el o f human incisors. Arch Oral Biol 11:11, 1081, 1966. 39. Plackova, A., and Stepanek, J. Submicroscopic struc­ tu re of th e enam el m em brane. Czas Stom at 66:1, 65, 1966. 40. Hay, D.l. Th e adsorption of salivary proteins by hydroxyapatite and enam el. Arch Oral Biol 12:8, 9 3 7 , 1967. 4 1 . Lehman, M.L. Tensile strength o f human dentin. J D ent Res 4 6 :1 , 197, 1967. 4 2 . Symons, N .B .B . Interglo bular dentine and th e calcospherite pattern. Arch Oral Biol 10:6, 1009, 1965. 43. Romans, M. M in eralization patterns of dentin o f hu­ man teeth . J Dent Res 4 5 :1 , 27, 1966.

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hum an predentin. Folia A nat Jap 4 1 :2 , 199, 1965. 73. Bennett, C.G.; K elln, E.E., and Biddington, W .R. Age changes of th e vascular pattern o f th e hum an dental pulp. Arch Oral Biol 10:6, 9 9 5 , 1965. 74. Upthegrove, D.D.; Bishop, J.G., and Dorm an, H.L. A m ethod for detection o f blood flo w in th e dental pulp. J Dent Res 45:4, 1115, 1966. 75. Riedel, H.; From m e, H.G., and Tallen , B. Electronm icroscopic investigations o f th e m orphology o f th e ca p il­ laries in th e human dental pulp. Arch Oral Biol 11 :11, 1049, 1966. 76. Main, J.H .P., and Adams, D. Experim ents on th e rat incisor into th e c e llu la r proliferation and blood-pressure theories of tooth erup tio n. Arch Oral Biol 11:2, 163, 1966. 77. Coady, J.M.; S antangelo, M.V., a n d T o to , P.D. Gam m airradiated mouse incisor. J D ent Res 4 6 :4 , 6 8 1 , 1967. 78. Bernick, S. V ascular and nerve supply to th e m olar teeth of guinea pigs. J D en t Res 4 5 :2 4 9 , 1966. 79. Bernick, S. Age changes in th e blood supply to human teeth. J Dent Res 4 6 :3 , 5 4 4 , 1967. 8 0 . Bernick, S. E ffe ct o f aging on th e nerve supply to hu­ man teeth. J Dent Res 4 6 :4 , 6 9 4 , 1967. 8 1 . Masterton, J.B. H ealing o f wounds o f th e dental pulp in man. Brit Dent J 12 0 :2 1 3 , 1966. 82. Sayegh, F.S. H ealing o f th e trau m atized dental pulp. J Dent Res 46 :5, 1036, 1967. 83. Dixon, A.D., and Peach, R. Fine stru ctu re of ep ith elial and connective tissue elem ents in human dental polyps. Arch Oral Biol 10:71, 1965. 84. Avery, J.K.; Han, S.S., and Lee, Y. Fine stru ctu re of th e incisor pulp o f gu inea pig during experim ental scurvy. J Dent Res 4 5 :440 , 1966. 85. Han, S.S.; Avery, J.K., and Bang, J.S. Th e e ffe c t of actinom ycin D on th e fib ro blast o f th e pulp o f th e rat in­ cisor. Arch Oral Biol 10 :503 , 1967. 8 6 . Han, S.S., and Avery, J.K. Fine structure o f in tercel­ lular substances and rounded cells in th e incisor pulp of th e guinea pig. Anat Rec 15 1:41 , 1965. 87. Pincus, P. M em b ran e in th e human tooth. N atu re 209: 5 0 2 0 , 31 7, 1966. 8 8 . Sulzm ann, R. Histology o f th e dental pulp. II. Dem on­ stration o f plasma cells and tissue m ast cells in perm anent m onoradicular teeth of dogs w ith th e lig ht and electron m i­ croscope. Anat Anz 119:2, 20 2, 1966. 89. Miyoshi, S.; N ish ijim a, S., and Im anishi, I. Electron m icroscopy of m yelinated and unm yelinated nerve fibers in human dental pulp. Arch Oral Biol 11:845, 1966. 90. Stockinger, L. N erve sections devoid o f perineurium . Acta Anat 60:2, 24 4, 1965. 91 . Pomerat, C.M ., and Contino, R.M. C ultivation o f den­ tal tissues. Oral Surg 19 :6 2 8 , 1965. 92 . Chiba, M. C ellu lar proliferation in th e tooth germ of th e rat incisor. Arch Oral Biol 10:707, 1965. 9 3 . Robins, M.W. The p roliferation of pulp cells in rat in­ cisors. Arch Oral Biol 12:487 , 1967. 9 4 . Pinzon, R.D.; Toto, P.D., and O 'M alley, J.J. K inetics of rat m olar pulp cells at various ages. J Dent Res 4 5 :3 , 93 4, 1966. 9 5 . Pinzon, R.D.; Kozlov, M ., and Burch, W .P. Histology of rat m olar pulp at d iffe re n t ages. J D ent Res 4 6 :1 , 2 0 2 , 1967. 9 6 . Goggins, J.F., and Fu llm er, H .M . Dehydrogenase histo­ chem istry of th e rat m olar pulp. Arch Oral Biol 11 :1365, 1966. 9 7 . H utowska-Lukasiew icz, M. H istochem ical exam ination of nucleic acids in th e dental pulp. Czas S tom at 18:10, 1185, 1965. 98 . Harris, R., and G riffin , C J . Aldehyde fu chsin-H alm i re­ action in fibers of th e hum an dental pulp. Arch Oral Biol 11:7, 64 9, 1966. 9 9 . G riffin, C.J., and Harris, R. U ltrastru ctu re of collagen fib rils and fibroblasts of th e developing human dental pulp. Arch Oral Biol 11:7, 65 9, 1966.

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100. Harris, R., and G riffin , C.J. Histogenesis of fib ro­ blasts in th e hum an dental pulp. Arch Oral Biol 12 :459 , 1967. 101. Han, S.S.; Avery, J.K., and Hale, L.E. Th e fin e struc­ tu re o f d iffe re n tia tin g fibroblasts in th e incisor pulp of the guinea pig. Anat Rec 15 3 :2 , 187, 1965. 102. Mjor, I.A., and S hackleford, J.M . Microradiography of hum an pulp tissue and decalcified coronal d entine. Arch Oral Biol 1 1 :130 7, 1966. 103. Rotblat, N .D ., and Yaegar, J.A. Dental pulp c itra te dur­ ing th e d evelopm ent o f abnorm ally m ineralized dentine. Arch Oral Biol 10:4, 6 1 7 , 1965. 104. Tonge, C.H. Advances in dental embryology. In t Dent J 16 :328 , 1966. 105. Koch, W .E. In vitro developm ent o f tooth rudim ents of em bryonic m ice. Anat Rec 15 2:513, 1965. 106. Koch, W .E. In vitro differen tiatio n of tooth rudim ents of em bryonic m ice. I. Tran sfilter interaction o f em bryonic incisor tissues. J Exp Biol 165:2, 155, 1967. 107. Glasstone, S. M orp ho differentiatio n o f teeth in em bry­ onic m and ibu lar segm ents in tissue culture. J D ent R e s 46:3, 6 1 1 , 1967. 108. Chiba, M. C ellu lar proliferation in th e tooth germ o f the rat incisor. Arch Oral Biol 10:4, 707, 1965. 109. Gaunt, W.A. Q u an titative aspects of th e developing tooth germ . J D ent Res (suppl) 46 :8 5 1 1967. 110. C ostacurta, L. Cell height and nuclear volum e in the enam el organ during am elogenesis in th e upper incisor of th e rat. J Dent Res 4 4 :1 2 4 7 , 1965. 111. Kallenbach, E.; Clerm ont, Y., and Leblond, C.P. The cell web in th e am eloblasts o f th e rat incisor. Anat Rec 153: 55, 1965. 112. Engler, W.O.; Ram fjord, S.P., and H iniker, J.J. M itotic potential of th e enam el organ of the rhesus m onkey. J Dent Res 4 4 :1 2 8 5 , 1965. 113. Chiba, M.; Nakagawa, K., and M im ura, T. Estim ation of m ito tic rate and m ito tic duration in th e in ternal enamel ep ith eliu m o f th e rat m axillary incisor using co lch icine tech­ nique. Arch Oral Biol 11 :803 , 1966. 114. K allenbach, E. Electron microscopy o f th e papillary layer o f th e rat incisor enam el organ during enam el m atura­ tio n. J U ltrastru ct Res 14:518, 1966. 115. Fischlschweiger, W.; Provenza, D.V., and Sisca, R.F. Reorganization of th e peripheral layer of the hum an enamel organ during th e bell stage—an electron m iscroscopic study. J B alti Coll Dent Surg 2 2 :1 , 28, 1967. 116. Sisca, R.F.; Provenza, D.V., and Fischlschweiger, W. U ltrastru ctu ra l ch aracteristics of th e hum an enam el organ in an early stage of developm ent. J B alti Coll Dent Surg 22: 1, 8 , 1967. 117. Decker, J.D. Th e fin e structure of th e developm ent of a vascular supply to th e rat m olar enam el organ. Arch Oral Biol 12:453, 1967. 118. Reith, E.J. The early stage of am elogenesis as ob­ served in m olar teeth of young rats. J U ltrastru ct Res 17:5, 50 3, 1967. 119. B ennett, I.C., and Law, D.B. Incorporation o f te tra ­ cycline in developing dog enam el and dentin. J D ent Res 44 :4, 78 8, 1965. 120. Bevelander, G., and Nakahara, H. Correlation between tetra cyc lin e binding and m ineralization of d entine and enam ­ el. Anat Rec 15 3:14 1, 1965. 121. Goren, A., and Gerstner, R. Autoradiographic localiza­ tion in fetal oral tissues of m aternally stored calcium 45. J Dent Res 4 4 :6 , 1272, 1965. 122. Hwang, W .S.S., and Tonna, E.A. A utoradiographic anal­ ysis of labelling indices and m igration rates of c e llu la r com ­ ponents of m ouse incisors using tritia te d th ym idin e. J Dent Res 4 4 :4 2 , 1965. 123. Stew art, J.M .; Claibourne, P.A., and Luikart, G.A. A histologic and histochem ical study of lipids in human odonto­ blasts. J D ent Res 4 4 :2 , 608, 1965. 124. Thonard, J.C. The effect of fraction al radiation on den­

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in keratinizing hum an oral epithelium . J U ltrastru ct Res 12: 3, 37 1, 1965. 152. W aterhouse, J.P., and Squier, C.A. Form and function of oral lysosomes in epithelium^ N ature 2 1 1 :4 2 0 , 1966. 153. W aterhouse, J.P., and Squier, C.A. T h e Langerhans cell in hum an gingival epith elium . Arch Oral Biol 12:341, 1967. 154. Barker, D.S. Th e dend ritic cell system in human gin­ gival epith elium . Arch Oral Biol 12:2, 20 3, 1967. 155. Squier, C.A., and W aterhouse, J.P. The u itrastructure of th e m elanocyte in hum an gingival epith elium . Arch Oral Biol 12:119, 1967. 156. H all, W .B. S tain in g m ast cells in human gingiva. Arch Oral Biol 11 :12, 1325, 1966. 157. W einstock, A., and Albright, J.T. The fin e structure of m ast cells in norm al hum an gingiva. J U ltrastru ct Res 17:3, 2 4 5 , 1967. 158. Gaunt, W.A. Som e observations upon th e histology of th e oral m ucosa o f th e albino mouse. Acta A nat 60 :4, 516, 1965. 159. M elcher, A.H. Gingival reticulin in h isto gen esis-of collagen fibers. J Dent Res 4 5 :4 2 6 , 1966. 160. M elcher, A.H. Histological recognition of gingival reticulin . Arch Oral Biol 11:2, 219, 1966. 161. M elcher, A.H. Th e nature o f th e “ basem ent m em brane” in human gingiva. Arch Oral Biol 10:5, 785, 1965. 162. Stern, I.B . E lectron m icroscopic observations of oral ep ith elium . P eriodontics 3:224, 1965. 163. Dhawan, A.S., and Toto, P.D. Renewal of cell popula­ tion in palate and tongue ep ith elia of m ice. J D ent Res 44: 9 8 9 , 1965. 164. Bowman, A.J., and Latham, R.A. M id palatal mucosa: persistence of a fetal pattern. J Dent Res 4 6 :2 9 5 , 1967. 165. Jepsen, A., and Theilade, J. Electron m icroscope iden­ tific a tio n of ep ith elial cells in tissue cu ltu re of oral m u­ cous m em brane. J Cell Biol 32 :3, 770, 1967. 166. Wolf, J. The gingivodental barrier in th e area o f the enam el. Parodontologie 19:4, 198, 1965. 167. Zussman, W.V. E ffe ct of oestrogens on th e dental epi­ th elia l attach m ent. Arch Oral Biol 10:315, 1965. 168. Listgarten, M.A. Electron m icroscopic study of the gingivo-dental ju n ctio n of man. Amer J Anat 11 9:14 7, 1966. 169. Listgarten, M.A. U ltrastru ctu re of enam el-epith elial junction in unerupted human teeth. Arch Oral Biol 11:999, 1966. 170. Porter, K., and Lefkowitz, W. Glycogen in developing and young rat oral ep ith elium . J Dent Res 4 4 :9 5 4 , 1965. 171. Nakam ura, R., and others. A lkaline and acid phospha­ tase activities in th e gingiva and alveolar bone in scurvy. Arch Oral Biol 10:5, 7 6 5 , 1965. 172. Smulow, J.B., and Glickm an, I. In vitro cultural and histochem ical characteristics o f human oral mucosa. Arch Oral Biol 11:11, 1143, 1966. 173. Steinberg, A.D., and Jeffay, H. Incorporation of radio­ active am ino acids into oral tissue proteins. J D ent Res 45: 81 2, 1966. 174. Sw ift, J.A., and Saxton, C.A. The ultrastructural loca­ tion o f th e p e rio date-S ch iff reactive basem ent m em brane a t th e derm oepiderm al junctions of human scalp and m on­ key gingiva. J U ltrastru ct Res 17:1, 23, 1967. 175. S m ith, C.J., and Cim asoni, G. Cholinesterases in buc­ cal and gingival mucosa of m onkey and man. Histochem ical dem onstration and e ffe c t of local anaesthetics. Arch Oral Biol 12:3, 34 9, 1967. 176. Murphy, T.R., and Thomson, J.M .D. The num ber and size of m yelinated fib ers in th e inferior alveolar nerve of a young sheep. Arch Oral Biol 11:307, 1966. 177. Alexander, R.W., and Fitzgerald, M.J.T. An exam ple of transm edian neurom uscular innervation. J Dent Res 46: 26 1, 1967. 178. Tolm an, D.E.; W inkelm ann, R.K., and Givilisco, J.A. N erve endings in gingival tissue. J Dent R e s 44 :4, 65 7, 1965.

179. M um ford, J.M . Pain perception threshold and ad apta­ tion of normal human te eth . Arch Oral Biol 10:6, 9 5 7 , 1965. 180. Ten Cate, A.R., and S helton, L. C holinesterase activity in human teeth. Arch Oral Biol 11:4, 4 2 3 , 1966. 181. Devoto, F.C.H.; Arias, N .H ., and Perrotto, B.M. Growth of rats’ lower incisor te eth a fte r un ilateral section of alveolar nerve. J D en t Res 4 5 :1 0 7 8 , 1966. 182. M a rtin elli, C., and R ulli, M .A. Th e innervation of chronic inflam m atory hum an periapical lesions. Arch Oral Biol 12:5, 593, 1967. 183. Karlsen, K. Location of m otor end plates and d istribu­ tion and histological stru ctu re of m uscle spindles in jaw m uscles o f the rat. Acta O dont Scand 2 3 :5 2 1 , 1965. 184. Marlow, C.D.; W inkelm ann, R.K., and Gibilisco, J.A. General sensory in nervation of th e hum an tongue. Anat Rec 1 5 2:503, 1965. 185. Marlow, C.D.; W inkelm ann, R.K., and G ibilisco, J.A. Special sensory innervation of th e human tongue. J Dent Res 4 4 :6 , 1381, 1965. 186. Kubota, K.; Fukuda, N., and Asakura, S. C om parative anatom ical and neurohistological observations on th e tongue o f the porcupine (H is trix c ris ta ta ). Anat R ec 15 5 :2 6 1 , 1966. 187. Kubota, K. C om parative anatom ical and neurohistolog­ ical observations on th e tongues o f elephants. A nat Rec 157: 50 5, 1967. 188. Gray, E.G., and W atkins, K.C. Electron m icroscopy of ta ste buds o f th e rat. Z Zellforsch 6 6 :5 8 3 , 1965. 189. Farbman, A .I. Fine stru ctu re of th e taste bud. J U ltra­ struct Res 12:3, 3 2 8 , 1965. 190. Murray, R.G., and M urray, A. Fine stru ctu re o f taste buds of rabbit fol ¡ate papil lae. J U ltrastru ct Res 1 9 :3 2 7 ,1 9 6 7 . 191. Bradley, R .M ., and S tern, I.B . T h e developm ent of the human taste bud during th e foetal period. J A nat 101:4, 743, 1967. 192. Brown, J.C. Observations on nuclei and central connec­ tions o f th e nervus trig e m in u s in th e hedgehog, E rinace us europa eus. Acta A nat 6 0 :3 8 2 , 1965. 193. Rhoton, A.L., Jr.; O ’Leary, J.L., and Ferguson, J.P. T h e trigem inal, facial, vagal, and glossopharyngeal nerves in th e monkey. A ffe re n t connections. Arch N eurol 14:530, 1966. 194. Johnston, M.C. A radioautographic study o f th e m igra­ tion and fa te of cranial neural crest cells in th e ch ick em ­ bryo. Anat Rec 15 6:14 3, 1966. 195. Humphrey, T. D evelopm ent of trigem in al nerve fibers to oral mucosa, com pared with developm ent to cutaneous surfaces. J Comp Neurol 12 6 :9 1 , 1966. 196. W inkler, G.F., and W olf, M .K . T h e developm ent and m aintenance of m yelin ated tissue cultu res o f rat trigem inal ganglion. Amer J Anat 11 9:2, 179, 1966. 197. Henderson, W .R. Th e anatom y of th e gasserian ganglion and the distribution of pain in relation to in jections and operations for trigem inal neuralgia. Ann Roy Coll Surg Engl 3 7 :346 , 1965. 198. Moses, H.L. C om parative fin e stru ctu re of th e trig e m i­ nal ganglia, including hum an autopsy studies. J Neurosurg 2 6:1, 112, 1967. 199. Shear, M . S tru ctu re and fu n ctio n o f m yoepithelial cells in salivary glands.-Arch Oral Biol 11:769 , 1966. 200. Tam arin, A. M yoepithelium o f th e rat subm axillary gland. J U ltrastru ct Res 16:3, 3 2 0 , 1966. 2 0 1 . Caram ia, F. U ltrastru ctu re o f mouse subm axillary gland. I. Sexual differences. J U ltrastru ct Res 16:5, 505, 1966. 20 2. Devi, N.S., and Jacoby, F. S ub m axillary gland o f the golden ham ster and its post-natal developm ent. J Anat 100: 26 9, 1966. 20 3. Alm gren, O., and others. C ellu lar localization of m ono­ am ine oxidase in rat salivary glands. Acta Physiol Scand 6 7 :2 1 , 1966. 2 0 4 . Ravetto, C.; Galluzzo, F., and Siervo, R. On th e pres­ ence o f sialic acid and sulph ate groups in rat subm axillary

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gland. J Histochem Cytochem 14:114, 1966. 2 0 5 . Santangelo, M .V ., and Toto, P.D. DNA m etabolism of th e m ouse subm andibular gland. J Dent Res 4 4 :1 3 0 4 , 1965. 2 0 6 . Sreebny, L.M.; W anam aker, B.B., and Robinovitch, M. D N ase of rat parotid gland. J D ent Res 4 4 :4 6 3 , 1965. 2 0 7 . C aldw ell, R.C., and Shackleford, J.M . A chem ical, im m unological and electron-m icroscopic study of c e n tri­ fuged human subm axillary saliva. Arch Oral Biol 12:3, 333, 1967. 2 0 8 . S antangelo, M .V., and Toto, P.D. Radiation effects on m ouse subm andibular gland. J Dent Res 4 4 :6 ,1 2 9 1 , 1965. 2 0 9 . Bhaskar, S.N .; Lilly, G.E., and Bhussry, B. Regenera­ tion o f th e salivary glands in th e rabbit. J Dent Res 4 5 :1 , 37, 1966. 2 1 0 . Shaw, J.H ., and Krumins, I. M astication, subm andib­ ular gland en largem en t and th e periodontal syndrome in th e rice rat. Arch Oral Biol 11:3, 279,-1 966 . 2 1 1 . T ravill, A. E ffe c t o f pregnancy on th e subm andibular glands o f m ice. Anat Rec 15 5:217, 1966. 2 1 2 . Kronman, J.H ., and Leventhal, M .M . A histochem ical study of th e e ffe c t o f im paired thyroid function and replace­ m en t therapy on th e mouse subm andibular gland. Arch Oral Biol 12:3, 3 6 7 , 1967. 21 3. Takaham a, N., and Barka, T. Electron m icroscopic al­ teratio n s of subm axillary gland produced by isoproterenol. J U ltrastru ct Res 17:5, 4 5 2 , 1967. 2 1 4 . Crouse, G.S., and Cucinotta, A.J. Progressive neu­ ronal d ifferen tiatio n in th e subm andibular ganglia of a series o f human fetuses. J Comp Neurol 12 5:25 9, 1965. 2 1 5 . Goldstein, M .N ., and Burdman, J.A. S tudies of th e nerve growth fa cto r in subm andibular glands of fem ale m ice treated w ith testosterone. Anat Rec 15 1:19 9, 1965. 21 6. Dixon, J.S. Th e fin e structure of parasym pathetic nerve c e lls in th e o tic ganglia of the rabbit. Anat Rec 156: 2 3 9 , 1966. 2 1 7 . Genis-Galvez, J.M .; Santos G utierrez, L., and M artin Lopez, M . Double innervation of th e parotid gland: experi­ mental. study. Acta A nat 63 :3 9 8 , 1966. 2 1 8 . M a rtin , W .D., Jr., and Sm ith, R.D. W eight changes of th e subm andibular glands in the rat resulting from denerva­ tio n. Anat Rec 15 6 :3 2 5 , 1966. 2 1 9 . Burdi, A.R. S agittal growth o f th e nasom axillary com ­ plex during th e second trim ester o f human prenatal develop­ m ent. J D en t Res 4 4 :1 1 2 , 1965. 2 2 0 . Burdi, A.R., and Lillie, J.H. A catenary analysis o f the m axillary dental arch during human embryogenesis. Anat Rec 15 4:13 , 1966. 2 2 1 . Bowman, A.J., and Latham, R.A. M id palatal mucosa: persistence of a fetal pattern . J Dent Res 46 :1, 29 5, 1967. 2 2 2 . Anderson, J.H.; Furstm an, L., and Bernick, S. Post­ nasal developm ent of th e rat palate. J D ent Res 4 6 :2 , 366, 1967. 2 2 3 . Hughes, L.V.; Furstm an, L., and Bernick, S. Prenatal developm ent of th e rat palate. J Dent Res 46:2, 3 7 3 , 1967. 2 2 4 . Chaudhry, A.P.; Schwartz, S., and Schm utz, J.A., Jr. E ffe cts o f cortisone and th alid om ide on m orphogenesis of secondary palate in A /H ej Mice. J Dent R e s 4 5 :6 ,1 7 6 7 , 1966. 2 2 5 . Jacobs, R .M . E ffe c t of vitam in A on p a late hydration in m ouse embryos. J D en t R e s 4 6 :1 , 31 0, 1967. 2 2 6 . C olem an, R.D. Developm ent of the rat palate. Anat Rec 1 5 1:10 7, 1965. 2 2 7 . Poswillo, D., and Roy, L.J. Pathogenesis o f c le ft palate: anim al study. B rit J Surg 52:902 , 1965. 2 2 8. Jordan, R.E.; Kraus, B.S., and Neptune, C .M . Dental ab no rm alities associated with c le ft lip and/or palate. C left P aiate J 3 :22, 1966. 2 2 9 . Reeve, W.L.; Porter, K., and Lefkowitz, W. In vitro closure of th e rat palate. J Dent Res 4 5 :1 3 7 5 , i9 6 6 . 2 3 0 . Chaudhry, A.P., and Siar, S. In vitro study of fusion o f palatal shelves in A/Jax mouse embryos. J D ent Res 46 :1, 2 5 7, 1967. 2 3 1 . Konegni, J.S., and others. Comparison o f standard or­

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gan cu ltu re and standard tran splant techniques in fusion of palatal processes of rat em bryos. C left P alate J 2:219, 1965. 2 3 2 . Burke, G.W., and others. Som e aspects o f th e origin and fa te of m idpalatal cysts in hum an fetuses. J Dent Res 4 5 :1 , 159, 1966. 23 3. Frazier, P.D.; Zipkin, I., and M ills, L.F. X-ray d iffrac­ tion study of hum an bone. Arch Oral Biol 12:73, 1967. 2 3 4 . Eanes, E.D., and others. S m all-an gle X-ray diffraction analysis o f th e e ffe c t o f flu o rid e on human bone apatite. Arch Oral Biol 10:1, 161, 1965. 23 5. M cConnell, D. Crystal ch em istry of hydroxyapatite. Its relation to bone m ineral. Arch Oral Bioi 10:3, 4 2 1 , 1965. 23 6. Rolle, G. H istochem istry o f bone form ation in normal and tetracycline-treated ch ick embryos. I. Lipkis. Arch Oral Biol 10:393, 1965. 2 3 7 . Epker, B.N ., and Frost, H .M . B iom echanical control of bone growth and developm ent: histological and tetracy­ cline study. J D ent Res 4 5 :3 6 4 , 1966. 23 8. Scheim an-Tagger, E., and Brodie, A.G. Lead acetate as a m arker o f grow ing ca lcified tissues. A m odified m ethod. A nat Rec 15 0:435, 1964. 23 9. Goldhaber, P. R em odeling o f bone in tissue culture. J Dent Res 4 5 :3, 4 9 0 , 1966. 24 0. Susi, F.R.; Goldhaber, P., and Jennings, J..M. Histo­ chem ical and biochem ical study o f acid phosphatase in resorbing bone in cu ltu re. A m er J Physiol 2 1 1 :9 5 9 , 1966. 24 1. Yeomans, J.D., and U rist, M .R . Bone induction by de­ calcified dentine im planted into oral, osseous and m uscle tissues. Arch Oral Biol 12:8, 9 9 9 , 1967. 24 2. Schulte, W.C. E ffect of an osteogenic extract on th e healing o f extraction wounds. J D ent Res 4 6 :4 , 65 6, 1967. 24 3. Steier, A., and others. E ffect o f vitam in D 2 and fluoride on experim ental bone fractu re healing in rats. J Dent Res 4 6 :4 , 67 5, 1967. 24 4. Cernavskis, N., and H unter, H.A. A study o f th e vascu­ lar pattern of th e rat m and ible using m icroangiography. J D ent Res 4 4 :6, 1264, 1965. 24 5. Huelke, D.F., and C astelli, W.A. Th e blood supply of th e rat m andible. Anat Rec 15 3:33 5, 1965. 2 4 6 . Bang, S., and Enlow, D .H . Postnatal growth of th e rabbit m andible. Arch Oral Biol 12:8, 9 9 3 , 1967. 24 7. C leall, J.F., and others. Expansion of th e m idpalatal suture in th e m onkey (M rh e su s). Angle O rthodont 35:23, 1965. 2 4 8 . Enlow, D.H ., arid Bang, S. Growth and rem odelling of th e human m axilla. Amer J O rthodont 51 :446 , 1965. 24 9. Bjork, A. S utu ral growth of th e upper face studied by th e im plant m ethod. Acta Odont Scand 2 4 :1 0 9 , 1966. 25 0. Enlow, D.H. M orphogenetic analysis o f fa cial growth. Amer J Orthodont 5 2 :2 8 3 , 1966. 25 1. Tracy, W.E.; Savara, B.S., and Brant, J.W.A. Relation of height, width and depth of th e m andible. Angle O rthodont 3 5 :2 6 9 , 1965. 252. Heath, M .R. C ephalom etric study of th e m idd le third of th e ad ult human face related to age and loss of dental tissue. Arch Oral Biol 11 :677 , 1966. 2 5 3 . Richardson, A. P attern of alveolar bone resorption follow ing extraction of an terior teeth . Dent Pract 16:77, 1965. 25 4. Pietrokovski, J., and Massler, M. Ridge rem odeling af­ te r tooth extraction in rats. J Dent Res 4 6 :1 , 22 2, 1967. 25 5. Sarnat, B.G., and W exler, M .R . Growth o f the face and jaws a fte r resection of th e septal cartilage in th e rabbit. Amer J Anat 118:3, 75 5, 1966. 25 6. Sprinz, R. Division o f th e neck o f th e m andible in rats. J Anat 101:4, 76 5, 1967. 257. Sharpe, C.J.; Gee, E.J., and G riffin , C.J. Osteogenic potential of th e human condyle. Aust D ent J 10:287, 1965. 2 5 8 . Oberg, T., and others. Vascularization o f th e m andib­ ular disk in th e guinea pig. O dont Rev 16:3, 159, 1965. 25 9. Blackwood, H.J.J. V ascularization of th e condylar

cartilage o f th e human m andible. J Anat 99:551, 1965. 260. Posselt, U., and T hilander, B. Influence o f innervation of th e tem porom andibular capsule on m andibular border movements. Acta Odont Scand 23:601, 1965. 261. Parsons, M.T., and Boucher, L.J. The bilam inar zone of th e m eniscus. J Dent Res 45:1, 59, 1966. 262. Blackwood, H.J.J. C e llular rem odeling in a rticu la r tissue. J Dent Res 45:3, 480, 1966. 263. Blackwood, H.J.J. Growth o f the m andibular condyle of th e rat (as shown by) using tritia te d th ym id in e . Arch Oral Biol 11:493, 1966. 264. Frommer, J. Prenatal developm ent of th e m andibular jo in t in m ice. Anat Rec 150:449, 1964. 265. Symons, N.B.B. A histochem ical study o f th e second­ ary ca rtilag e o f the m andibular condyle in the rat. Arch Oral Biol 10:4, 579, 1965. 266. Frommer, J., and Monroe, C.W. Development and d is trib u tio n o f e la stic fib e rs in th e m andibular jo in t of the mouse. A com parison of fetal, suckling, ju ve n ile and a d u lt stages. Anat Rec 156:333, 1966. 267. Frommer, J., and Monroe, C.W. The nature o f the p eri­ a rtic u la r tissues o f th e m an dibular jo in t in th e mouse and rat. Arch Oral Biol 11:947, 1966. 268. Furstm an, L.L. Normal age changes in th e rat m andib­ ular jo in t. J Dent Res 45:2, 291, 1966. 269. Frommer, J., and Monroe, C.W. The m orphology and d is trib u tio n o f nerve fib e rs and endings associated w ith the m andibular jo in t o f th e mouse. J Dent Res 45:1762, 1966. 270. G reenfield, B.E., and Wyke, B. Reflex innervation of the tem porom andibular jo in t. N ature 211:940, 1966.

271. M offett, B. M orphogenesis of th e tem porom andibular jo in t. A m erJ O rthodont 52:401, 1966. 272. Vuodelis, R.A. O ssification o f th e human tem porom an­ d ib u la r jo in t. J Dent Res 45:1, 192, 1966. 273. Yuodelis, R.A. The morphogenesis o f th e human tem ­ porom andibular jo in t and its associated structures. J Dent Res 45:1, 182, 1966. 274. Das, A.; Meyer, J., and Sicher, H. X-ray and alizarin studies on the e ffe c t o f b ila te ra l condylectom y in th e rat. Angle O rthodont 35:138, 1965. 275. Furstm an, L. E ffect o f loss o f occlusion upon th e man­ d ib u la r jo in t. Am er J O rthodont 51:245, 1965. 276. Gianelly, A.A., and Moorrees, C.F.A. C ondylectom y in th e rat. Arch Oral Biol 10:101, 1965. 277. Peskin, S., and Laskin, D.M. C o n trib u tio n o f autogenous condylar g ra fts to m an dibular growth. Oral Surg 20:517, 1965. 278. Hayes, A.M. H istologic study of regeneration o f th e m an d ib u la r condyle a fte r u n ila te ra l condylectom y in the rat. J Dent Res 46:3, 483, 1967. 279. Schneider, B.J., and Meyer, J. In te rre la tion s o f con­ dylar growth and alveolar bone fo rm a tio n (in rats). Angle O rthodont 35:187, 1965. 280. Irving, J.T., and Durkin, J.F. A com parison o f th e changes in th e m andibular condyle w ith those in th e upper tib ia l epiphysis d u rin g th e onset and healing o f scurvy. Arch Oral Biol 10:1, 179, 1965. 281. Hedegard, B., and Lundberg, M. Tem porom andibular jo in t (changes) in pa tie nts w ith im m ediate upper dentures. Acta O dont Scand 23:163, 1965.

The bright lights reflect the after-dark entertainm ent available in Miami Beach, the site of the 109th annual session of the American Dental Association, October 27-31, 1968.

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