Rachel Sarig

Middle pleistocene dental remains from Qesem Cave (Israel)

This study presents a description and comparative analysis of Middle Pleistocene permanent and deciduous teeth from the site of Qesem Cave (Israel). All of the human fossils are assigned to the Acheulo-Yabrudian Cultural Complex (AYCC) of the late Lower Paleolithic. The Middle Pleistocene age of the Qesem teeth (400-200 ka) places them chronologically earlier than the bulk of fossil hominin specimens previously known from southwest Asia. Three permanent mandibular teeth (C(1) -P(4) ) were found in close proximity in the lower part of the stratigraphic sequence. The small metric dimensions of the crowns indicate a considerable degree of dental reduction although the roots are long and robust. In contrast, three isolated permanent maxillary teeth (I(2) , C(1) , and M(3) ) and two isolated deciduous teeth that were found within the upper part of the sequence are much larger and show some plesiomorphous traits similar to those of the Skhul/Qafzeh specimens. Although none of the Qesem teeth shows a suite of Neanderthal characters, a few traits may suggest some affinities with members of the Neanderthal evolutionary lineage. However, the balance of the evidence suggests a closer similarity with the Skhul/Qafzeh dental material, although many of these resemblances likely represent plesiomorphous features.

The earliest modern humans outside Africa

Earliest modern humans out of Africa Recent paleoanthropological studies have suggested that modern humans migrated from Africa as early as the beginning of the Late Pleistocene, 120,000 years ago. Hershkovitz et al. now suggest that early modern humans were already present outside of Africa more than 55,000 years earlier (see the Perspective by Stringer and Galway-Witham). During excavations of sediments at Mount Carmel, Israel, they found a fossil of a mouth part, a left hemimaxilla, with almost complete dentition. The sediments contain a series of well-defined hearths and a rich stone-based industry, as well as abundant animal remains. Analysis of the human remains, and dating of the site and the fossil itself, indicate a likely age of at least 177,000 years for the fossil—making it the oldest member of the Homo sapiens clade found outside Africa. Science, this issue p. 456; see also p. 389 Fossilized mouthparts indicate the presence of Homo sapiens in the Levant 160,000 years ago. To date, the earliest modern human fossils found outside of Africa are dated to around 90,000 to 120,000 years ago at the Levantine sites of Skhul and Qafzeh. A maxilla and associated dentition recently discovered at Misliya Cave, Israel, was dated to 177,000 to 194,000 years ago, suggesting that members of the Homo sapiens clade left Africa earlier than previously thought. This finding changes our view on modern human dispersal and is consistent with recent genetic studies, which have posited the possibility of an earlier dispersal of Homo sapiens around 220,000 years ago. The Misliya maxilla is associated with full-fledged Levallois technology in the Levant, suggesting that the emergence of this technology is linked to the appearance of Homo sapiens in the region, as has been documented in Africa.

Socioeconomic and physical characteristics of individuals with degenerative lumbar spinal stenosis.

Study Design. A descriptive study of the association between demographic factors, and physical characteristics, and degenerative lumbar spinal stenosis (DLSS). Objective. To shed light on the association between socioeconomic parameters, physical characteristics, and DLSS. Summary of Background Data. Lumbar spinal stenosis is a prevalent and disabling condition in the aging population. DLSS is considered to be the most common type and is essentially associated with disc disease, facet joint arthrosis, ligamentum flavum thickening, and osteophyte formation. Although there is ample information regarding the association between body mass index, cardiovascular disorders, smoking habits, and disc disease, very little is known about their association with DLSS. Data on the association of body physique (e.g., height and weight) and DLSS are limited. Methods. Two sample populations were studied. The first included 165 individuals with DLSS (mean age, 64 ± 9.9 yr) and the second 180 individuals without spinal stenosis related symptoms (mean age, 62.5 ± 12.6 yr). An evaluation of the cross-sectional area of the dural sac and degenerative listhesis for all participants was performed using computed tomographic lumbar spine images, obtained by Philips EBW station (Brilliance 64, Philips Medical System, Cleveland, OH). All participants were interviewed to obtain demographic, physical, and health data. Independent t test, Mann-Whitney and &khgr;2 tests were used to determine the association between parametric and nonparametric variables and DLSS. Logistic regression analysis was carried out to reveal predicting variables for DLSS. Results. Females with stenosis were significantly heavier and shorter than their counterparts in the control group. We also noticed that they delivered babies more often than those in the control group. Prevalence of individuals experiencing diabetes mellitus was significantly higher in the males with stenosis than control group. In the stenosis group, the frequencies of individuals engaged in heavy manual labor (males) and housekeeping (females) were significantly higher than that of their counterparts in the control group. Conclusion. Heavy manual labor and diabetes mellitus in males and housekeeping (females) play major roles in the genesis of DLSS.

Malocclusion in Early Anatomically Modern Human: A Reflection on the Etiology of Modern Dental Misalignment

Malocclusions are common in modern populations. Yet, as the study of occlusion requires an almost intact dentition in both the maxilla and mandible, searching for the ultimate cause of malocclusion is a challenge: relatively little ancient material is available for research on occlusal states. The Qafzeh 9 skull is unique, as its preserved dentition allowed us to investigate the presence and manifestations of malocclusion. The aim of this study was thus to examine the occlusal condition in the Qafzeh 9 specimen in light of modern knowledge regarding the etiology of malocclusion. We revealed a pathologic occlusion in the Qafzeh 9 skull that probably originated in the early developmental stage of the dentition, and was aggravated by forces applied by mastication. When arch continuity is interrupted due to misalignment of teeth as in this case, force transmission is not equal on both sides, causing intra-arch outcomes such as mesialization of the teeth, midline deviation, rotations and the aggravation of crowding. All are evident in the Qafzeh 9 skull: the midline deviates to the left; the incisors rotate mesio-buccally; the left segment is constricted; the left first molar is buccally positioned and the left premolars palatally tilted. The inter-arch evaluation revealed anterior cross bite with functional shift that might affect force transmission and bite force. In conclusion, the findings of the current study suggest that malocclusion of developmental origin was already present in early anatomically modern humans (AMH) (the present case being the oldest known case, dated to ca. 100,000 years); that there is no basis to the notion that early AMH had a better adjustment between teeth and jaw size; and that jaw-teeth size discrepancy could be found in prehistoric populations and is not a recent phenomenon.

The arrangement of the interproximal interfaces in the human permanent dentition

ObjectivesThe interproximal interface (IPI) is the interface between two adjacent teeth, i.e., the site where forces are transmitted along the dental arch. We investigated the IPI arrangement of the human permanent dentition. Specifically, the IPI morphometrical characteristics were studied and interpreted within a biomechanical framework.Subjects and methodsA novel in vivo IPI measurement was developed based on diversity in transillumination of Polyvinyl siloxane impression of the interproximal region. The study group included 30 subjects, aged 27, ±4.0xa0years. Eleven parameters were examined in each of the 26 IPIs of the permanent dentition.ResultsThe IPI showed intra-arch similarity and interarch diversity between the tooth groups. The IPI shape was predominantly oval (60–100xa0%), yet kidney-shaped in some molars (22–40xa0%). From incisors to molars: the IPI increased significantly (pu2009<u20090.001) in size (1.72 to 6.05xa0mm2), occupied more of the proximal wall (7.8–12xa0%), changed its orientation from vertical to horizontal (88.66–14.80°), and was mainly located in the buccal–occlusal quadrant of the proximal wall, chiefly in the molar teeth.ConclusionsThe IPI is a product of proximal wall attrition and is dictated by the mastication forces, number of cusps, and crown inclination. IPI arrangement counteracts the adverse crowding effect of the anterior component of the mastication forces.Clinical relevanceThe IPI characteristics found in the present study provide guidelines for crown and proximal filling restorations to meet dental physiology requirements. Further, IPI determines correct tooth alignment and proximal wall stripping applied to resolve arch length deficiency.

Pattern of maxillary and mandibular proximal enamel thickness at the contact area of the permanent dentition from first molar to first molar

INTRODUCTIONnProximal enamel thickness (PET) at the mesial and distal contact areas of the complete permanent dentition has not been previously reported. Anatomic investigation of PET is essential for interproximal reduction treatment. Our objectives were to measure the PETs of the complete maxillary and mandibular dentitions at the contact areas, to compare the PETs of adjacent teeth, and to evaluate the vertical position of each contact area.nnnMETHODSnWe evaluated 720 extracted teeth; of these, 109 intact teeth were selected. The mesial and distal contact areas were demarcated, and each tooth was embedded in transparent epoxy resin. Blocks were prepared so that the 2 demarcated contact areas were exposed, and 6 measurements were taken and statistically analyzed.nnnRESULTSnBoth jaws showed the same PET pattern characterized by 5 features: PET increased progressively from incisor (0.63 mm) to first molar (1.48 mm). Per tooth, mesial and distal PET did not differ. Total maxillary (26.86 mm) and mandibular (24.52 mm) PETs were similar. Paired PETs at the interproximal interface were similar, with the exception of the lateral incisor-canine interfaces. From incisor to first molar, the contact area becomes located farther gingivally.nnnCONCLUSIONSnThe existing guideline of maximal 0.5-mm interproximal reduction per 2 adjacent teeth should be kept in the anterior region and could be increased to 1 mm in the posterior region, when an equal amount is removed.

A Possible Case of Cherubism in a 17th-Century Korean Mummy

Cherubism is a benign fibro-osseous disease of childhood limited specifically to the maxilla and mandible. The progressive replacement of the jaw bones with expansile multilocular cystic lesions causes eventual prominence of the lower face, and hence the classic “cherubic” phenotype reflecting variable extents of jaw hypertrophy. Histologically, this condition has been characterized as replacement of the normal bone matrix with multicystic pockets of fibrous stroma and osteoclastic giant cells. Because of radiographic features common to both, primarily the presence of multiloculated lucencies with heterogeneous “ground-glass” sclerosis on CT imaging, cherubism was long mistaken for a craniofacial subtype of fibrous dysplasia. In 1999, however, the distinct genetic basis for cherubism was mapped to chromosome 4p16.3 and the SH-3 binding protein SH3BP2. But while there are already three suspected cases of fibrous dysplasia amongst archaeological populations, no definitive cases of cherubism have yet been reported in historical populations. In the current study we describe micro- and macro-structural changes in the face of a 17th century Joseon Dynasty Korean mummy which may coincide with the clinic-pathologic and radiologic features of cherubism.

Proximal attrition facets: morphometric, demographic, and aging characteristics

Although interproximal attrition is considered to be limited in modern populations, it has important clinical implications. However, in contrast to occlusal attrition, proximal attrition receives limited scientific attention. The main purpose of the current study was to fill this void. Seven-hundred and sixty-five teeth were collected from 255 skulls of subjects 18-75 yr of age. For each individual, three mandibular teeth (the first and second premolars and the first molar) were examined for proximal attrition facets (PAFs). The results provide detailed information on the size, shape, and location of the facets according to age cohort, gender, and ethnicity. The validity of the method used to measure the facets was also examined. The major findings were as follows: PAFs are usually located on the upper half of the crown proximal aspect; in each tooth, the mesial facet is more lingually positioned and the distal facet is more buccally positioned; the majority of the facets are subrectangular in shape; the size of the facets tends to increase in an anteroposterior direction (from premolars to molars); and facet size and location are age- and sex-dependent and ethnicity-independent. It is our recommendation that dentists bear in mind that interproximal attrition is a dynamic, long-term process and needs to be considered in many clinical scenarios.

Efficacy of three hygienic protocols in reducing biofilm adherence to removable thermoplastic appliance

OBJECTIVESnTo examine the ability of a removable thermoplastic appliance (RTA) to adsorb hygienic solutions and inhibit bacterial growth and to examine the efficacy of three hygiene protocols in reducing bacterial biofilm adherence to RTA.nnnMATERIALS AND METHODSnSolution adsorption and bacterial growth inhibition were examined in vitro using paper vs RTA discs. Subsequently, 11 patients treated with RTA (mean age, 29.1 ± 4.7 years) were assigned into a sequence of three hygiene protocols: regular RTA brushing (baseline), immersion RTAs in chlorhexidine mouthwash (CHX), and using a vibrating bath with cleaning solution (VBC). For each patient, 12 upper RTAs were examined (2 baseline RTAs, 5 CHX RTAs, and 5 VBC RTAs), for a total of 132 RTAs. All RTAs were stained with gentian violet, and biofilm presence was measured using a photodensitometer.nnnRESULTSnThe RTA discs did not adsorb CHX or cleaning solution. The later agent did not show antibacterial features. Baseline RTAs showed significant biofilm adherence (P < .001) on the posterior palatal side of the aligner and on the anterior incisal edge. CHX and VBC hygienic protocols significantly (P < .001) reduced baseline biofilm adherence by 16% and 50%, respectively. Hygienic improvement was maintained over 140 days when CHX and VBC were used. However, VBC was three times more efficient than CHX.nnnCONCLUSIONSnThis study highly recommends the use of a VBC protocol. Biofilm deposits on the RTA, especially on incisal edges and attachment dimples, could lead to inadequate tooth/RTA and attachment/RTA overlap and consequently impair tooth alignment.

The plastered skulls from the Pre-Pottery Neolithic B site of Yiftahel (Israel)--a computed tomography-based analysis.

Three plastered skulls, dating to the Pre-Pottery Neolithic B, were found at the site of Yiftahel, in the Lower Galilee (Israel). The skulls underwent refitting and restoration processes, details of which are described herein. All three belong to adults, of which two appear to be males and one appears to be a female. Virtual cross-sections were studied and a density analysis of the plaster was performed using computed tomography scans. These were utilized to yield information regarding the modeling process. Similarities and differences between the Yiftahel and other plastered skulls from the Levant are examined. The possible role of skull plastering within a society undergoing a shift from a hunting-gathering way of life to a food producing strategy is discussed.