GSDM: Historical Theses and Dissertations (Open Access)

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This is a historical collection of GSDM Theses and Dissertations that were originally submitted in print from 1964-2015. With permission from the authors, we have been able to make these openly accessible. For more recent Dental School theses and dissertations, please go to the BU Theses & Dissertations Collection: https://open.bu.edu/handle/2144/8520.

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Now showing 1 - 20 of 269

An analysis of orthodontic relapse
(Boston University, 1973) Pezza, Joseph E.
Orthodontic treatment often changes a patient’s appearance so radically, that his very personality is greatly improved. Even minor orthodontic changes are rewarding and satisfying to both the orthodontist and the patient. If there is to be one area in orthodontic results which promotes disappointment and frustration most often, relapse must be this area. Thus, it is the intention of this paper to present the incidence of retention problems, specifically lower incisor recrowding, intercanine and intermolar width stability, rotational stability, activity of extraction sites, and the influence of third molars on the extraction site and on the incisor recrowding. Forty-two cases were selected which underwent and completed active orthodontic treatment. Their records taken two to four years after treatment were compared to records taken at the time of treatment completion and again compared to their pre-treatment records. The data were analyzed. The results indicated that lower incisor recrowding is the most common occurrence, intercanine and intermolar expansion during treatment is not stable, rotational relapse is high, opening of extraction spaces is common, and the influence of third molars is highly questionable. Due to the limited number of cases examined it is not clinically significant to draw accurate conclusions. However, the results show correlations among the various relapse areas. Favorable progress has been made in an attempt to solve the retentions problem, but much further research is needed in this area.
Quantitative study of the effect of moisture on Kerr's root canal sealer's setting time
(Boston University, 1978) Zequeira, Maria D.
This study was performed to determine the effect of moisture on the setting time of Kerr's Root Canal Sealer. It was found that moisture in the following places decreased the setting time: 1. Liquid of sealer (left open to ambiental conditions it will pick up moisture). 2. Mixing surface and mixing instruments (eye dropper, glass slab and spatula). 3. Root canal system 4. Ambiental conditions
A survey of complete denture prosthesis service by means of a questionnaire
(Boston University, 1975) Yulzari, Jean-Claude
Success of complete denture construction is usually evaluated by two persons. In the first place the dentist evaluates and approves his own work prior to insertion which in second place is approved and accepted by the patient. In general few opportunities are given to patients to express their feelings of satisfaction or dissatisfaction. A study was therefore designed to allow patients that received complete denture care to express their complaints and satisfaction in a questionnaire which was sent out by mail to one hundred patients. Another group of ninety patients were approached directly and interviewed personally. Some questions in the questionnaire were broad, others were very specific. The analysis of data was arranged in three categories; age, sex, and satisfaction. The results of this study are essentially in agreement with the few studies performed by other investigators. 81% of the patients claim to be satisfied and men are easier to please than women. From the data it appears that the most difficult group appears to bbe the 60 to 70 years of age group. Although a high percentage of satisfaction was recorded specific questions revealed less optimistic feelings about fit of the dentures, mastication, speech and esthetics. Psychological acceptance of complete dentures is a definite factor associated with successful treatment. Another finding of interest was the fact that only 17% of the test population would advise other people to seek complete denture treatment. The amount of data collected was so enormous that statistical analysis of all possible combinations would require a huge amount of time. The data is still open for analysis however and based on the same questionnaire or modifications thereof a larger population can be investigated to see whether the results are valuable or not.
Aging of dental gutta-percha
(Boston University, 1981) Yu, Donald C.
Gutta-percha is the natural form of trans-1, 4-polyisoprene from trees belonging to the genus Dichopsis. It has been used by dentists for at least 130 years as a compounded mixture of gutta hydrocarbon, zinc oxide, barium sulfate, waxes, resins such as albane, fluavil and coloring agent. However, its physical, mechanical properties have never been elicited until this decade. In 1967, Dr. Schilder (140) at Boston introduced the warm gutta-percha technique to the dental profession. This technique includes the vertical compaction of warm gutta percha together with a sealer into the entire complesities of the root canal system three dimensionally. Since the introduction of this modern concept and unique method of accomplishing successful result most predictably, studies on dental gutta-percha concerning its physical properties, mechanical properties, molecular structure, chemistry, composition by improved scientific facilities and investigative capabilities are now in full swing. With the comprehensive knowledge of the material science, biologic concept, clinical technique and judgement, endodontic care can then be delivered to the public at the highest quality. This study was attempted toward the investigation of the aging of dental gutta-percha so that a method of storing the dental gutta-percha is formulated. One of the most important characteristics of gutta-percha for commercial purposes is its aging which may be assumed to vary according to conditions of storage and use. Two primary classes of physical tests were performed on the dental gutta-percha products from different manufacturers namely Mynol, Hygenic, Kerr and Unitek. The first class consists of tests designed to measure 1) the hardness indentation and 2) bending property. The second class is directed toward the determination of the variables or factors possibly affecting the clinical service value of the guttapercha. These storage variables include 1) oxygen, 2) temperature, 3) ultra-violet light and ozone; 4) alcohol, 5) saline and 6) 2.5% of sodium hypochlorite solution. The results of this study indicates that all the four endodontic gutta-percha specimens behave the similar aging process, Oxygen itself alone, without any other catalysts such as ultra-violet light or heat, will not accelerate the aging effect such as brittleness against bending. However, the specimens stored at 65°c for 3O days, the endodontic gutta-percha cones are brittle and are no longer usable for all clinical purposes. Ultra-violet light acts as a catalyst causing the aging of endodontic gutta-percha. Alcohol and saline apparently help to retard the aging process. Fresh endodontic gutta-percha shows a modified Brinell Hardness Number of 2.84, and the aged (65°c for 30 days) specimens show 4.97. This study also demonstrates that dental gutta-percha is an autooxidative substance which is autocatalytic with a induction period of about 20 days when subject to a temperature of 65°c.
An evaluation of the effects and interactions of several factors upon the cementation of cast metal crowns
(Boston University, 1990) Wang, Chu-June
This study evaluates the effects and interactions of cements, cement space, seating forces, marginal designs and bite materials on crown seating upon cementation. Two stainless steel dies of 6 mm crown preparations with 10 degree axial tapers were used. Both were designed with 1 mm wide shoulders, one with a simple shoulder, the other, a shoulder with a 65 degree bevel. Ten impressions (Impregum, Premier) were made from each die and poured in die stone (Super-Die, Whip Mix). Four coats of die-spacer (Tru-Fit, Taub.) were painted on 5 dies of each type. The dies were divided into 4 groups as follows: spacer; B: shoulder, no die-spacer; A: shoulder, with die C: shoulder-bevel, with die-spacer; D: shoulder-bevel, waxed up on all dies and cast no die-spacer. Crowns were in Rexillium (Rx Jeneric). Before and after cementation, the seating of crowns on metal dies was measured with a micrometer (Starrett). Comparisons were made between zinc phosphate cement (Mizzy, Fleck's) and ionomer cement (Ketac-Cem, Premier) under 2 seating forces (5 and 30 pounds) in an Instron machine using an orangewood stick (Aidaco, Interstate) or the E-Z-bite (Gingipak). Five pairs of dead flat metal disks (2 mm thick, 11 mm in diameter) were also used to test the cement film thickness attributable to the use of the above-mentioned cements, seating forces, and bite materials. The use of ANOVA and Newman Keuls tests revealed that die-spacer, heavy force (30 pounds), glass ionomer cement (Ketac-Cem) all significantly improve crown seating upon cementation. Die-spaced shoulder bevel preparations yielded superior crown seating when 30 pounds of force or ionomer cement (Ketac-Cem) were used. Orangewood stick and E-Z-bite were equivalent in effectiveness.
An evaluation of master cast techniques for multiple abutment implant prostheses
(Boston University, 1991) Vigolo, Paolo
This study evaluates the accuracy of three different techniques used to obtain a master cast for the construction of a prosthesis that will fit passively onto osseointegrated implants. A machined metal model with six fixtures and abutments and a matching template were fabricated. Impressions of this master model were taken and poured in stone. The master casts were divided into three groups of fifteen as follows: 1. Solid 2. Pindex-sectioned 3. Zeiser-sectioned Each master cast was evaluated for the accuracy with which the template passively fit the abutment replicas. Clinical judgment was assisted by the use of an optical comparator. Only those master casts sectioned with the Zeiser system allowed an accurate passive fit of the template. This conclusion is attributable to the predetermination of die positions prior to pouring impressions that is the distinguishing feature of the Zeiser system.
Ultrastructural study of the skeletal muscle fibers in the diabetic Chinese hamster
(Boston University, 1976) Vecchini, Marcos F.
A study of skeletal muscle fiber biopsies from the tongue and soleus muscle of diabetic Chinese hamsters revealed the presence of lipid droplets within the muscle fibers. These droplets were found in the cytoplasm near a mitochondria, partially inside or surrounded by one or more mitochondrium. Glycogen granules were found in great quantities in the cytoplasm of the tongue and soleus muscle. These granules were also found within the mitochondria of the tongue muscle.
Connective tissue growth factor in human gingiva, and studies of lysyl oxidase processing proteinases
(Boston University, 2001) Uzel, Mehmet Ilhan
The first part of our studies is focused on gingival overgrowth. Gingival overgrowth is characterized by excess extracellular matrix (ECM) accumulation. TGF-J31 regulation of connective tissue growth factor (CTGF) was assessed for the first time in human gingival cells and tissues. CTGF protein is strongly induced by TGF-J31 in human gingival fibroblasts. Exogenous addition of CTGF to gingival fibroblasts stimulates production of lysyl oxidase enzyme activity up to 1.5-fold after 48 hours, and 50 ng/ml CTGF stimulated insoluble collagen accumulation by only 1.5 to 2.0 fold after 4 to18 days of treatment. Thus, although CTGF itself contributes to increased insoluble collagenous extracellular matrix accumulation, CTGF does not mediate more potent effects of TGF-J31. Gingival overgrowth samples obtained from patients undergoing therapy with phenytoin, nifedipine, and cyclosporin A and control tissues from systemically healthy donors were subjected to immunohistochemistry by staining with CTGF, and TGF-J3 l antibodies. The results indicate for the first time increased levels of CTGF protein in overgrown gingival tissues, particularly in phenytoin induced gingival overgrowth. The second part of our studies is focused on the Bmpl-related genes. The Bmpl gene encodes bone morphogenetic protein 1 (BMP-1) and mammalian Tolloid-like (mTLD), both of which have procollagen C-proteinase activity. Two BMP-1/mTLDrelated protease genes named mammalian Tolloid-like 1 and 2 (Till and Tll2) have recently been described. The present study determines and compares the abilities of recombinant BMP-1, mTLD, mTLL-1, and mTLL-2 to process a recombinant pro-lysyl oxidase fusion protein in vitro. Results suggest that recombinant BMP-1, mTLD, and mTLL-1 productively cleave pro-lysyl oxidase at the correct physiological site in vitro, and that BMP-1 itself appears to be the most efficient lysyl oxidase processing activity while mTLL-2 was shown to process pro-lysyl oxidase slowly in vitro. These studies suggest that pro-lysyl oxidase processing may depend principally on the presence of Bmpl gene products, and that mTLL-1, and mTLL-2 may contribute to pro-lysyl oxidase processing.
An investigation of dental student's attitudes towards the elderly
(Boston University, 1983) Underhill, Susan M.
Demographic data indicates that the elderly population of the United States has been increasing in size and will continue to do so. Studies indicate that health professionals possess negative stereotypes for this age group and are generally disinclined to accept them as patients. Current trends in professional health education attempt to minimize these attitudes through interdisciplinary instruction and increased clinical experience with the elderly. An attitudinal survey designed by the investigator was administered at the beginning and end of a four month time interval to the second, third, and fourth year students at a private dental school in Boston, Massachusetts. The purpose was to determine if there was a difference in the attitudes toward the elderly held by students at the three stages in their dental education. In addition, the effect that an extramural geriatric screening program had on the attitudes of an experimental group of participants was evaluated through a comparison of their attitudes to those of a non-participating control group of students. Results of the survey indicated that a statistical difference in attitudes did exist among students in the class levels which was incrememtally positive over the three years. Data analysis also indicated that participation in the extramural geriatric program did not further increase the existing positive attitudes of the experimental group of students.
Contrast ratio and masking ability of pressed veneers as a function of their thickness and resin cement variables
(Boston University, 2009) Succaria, Faysal
Objectives: The restoration of discolored teeth using ceramic veneers is an accepted conservative treatment modality. However, due to the translucency and limited thickness of the ceramic veneers, their color could be affected by the underlying cement and the shade of the substrate. This study aims to evaluate the effect of both the thickness of the pressed ceramic and the cement used on the optical properties of the veneers. Materials and Methods: The experiment was conducted in two parts. In the first part, disk-shaped samples of IPS e.max Press Low Translucency shade 81 were fabricated in two thicknesses: 0.Smm(n=18) and 0.8mm(n=18). A spectrophotometer, ColorIS (Xrite, USA), was used to measure the contrast ratio (CR), the translucency parameter (TP), and the color differences of the samples when placed over an A4 and 81 backgrounds (LiE [S(A4 backing), S(Bl backing)]). In the second part of the experiment, six resin cement shades in two systems were applied to the original e.max samples and pressed against a glass slab. The samples were cured then separated from the glass. The six cements used where RelyX Veneer cement (Shades: White Opaque, 80.5, and A1) and Choice 2 Veneer cement (Shades: Milky Bright, A1, and 81). Groups were again tested for CR, TP, and color change over two backgrounds A4 and B1. T-test, One way ANOVA and Tukey, as well as paired t-test were used to analyze the data. Results: Independent t-test results suggest that the two groups of thicknesses of e.max (0.5mm and 0.8mm) were significantly different in all three parameters tested (P[less than]0.01). For the e.max with cement groups, AN OVA and Tukey's post-hoc tests were performed to study the effect of varying the cement brand and shade. The results suggest that the groups of different cements used with 0.5mm e.max were significantly different. However, when using 0.8mm e.max, there were no significant differences between the cements (P[less than]0.05). All 0.8 mm e.max groups exhibited significantly higher opacity and masking ability values than 0.5mm e.max groups except for 0.5mm e.max with RelyX WO and Choice 2 MB. The paired t-test of samples with and without cement suggests that RelyX veneer WO and Choice2 veneer cements significantly improved opacity and masking ability of 0.5mm e.max. However, the remaining 4 cements used in conjunction with 0.5mm e.max and all cements tested with 0.8mm e.max did not exhibit any significant difference. The three parameters tested were strongly correlated with Pearson correlation values above 0.9. Conclusions: Varying the thickness and the cement shade significantly affected opacity and masking ability. For 0.8mm e.max, none of the cements tested contributed to opacity and masking ability. Two cements (RelyX Veneer WO and Choice 2 MB) increased the opacity and masking ability of 0.5mm e.max comparable to 0.8mm e.max values. None of the groups tested achieved full masking.
A survey of dental needs and the problems of dental care delivery in three nursing homes
(Boston University, 1976) Stevenson, Sheila
An investigation of an electronic heat transfer instrument
(Boston University, 1984) Stephens, James R.
Dentists have heated gutta percha using a variety of methods for at least 130 years. Warmed gutta percha is easily deformed and suited the needs of restorative dentists as well as endodontists. For more than 20 years, the Schilder OOP heat carrier has been the instrument of choice for transferring heat during the vertical compaction of warm gutta percha. Recently, however, an electronic instrument has been manufactured which produces heat at the tip of a specially designed heat probe. Prior to this study, no information existed regarding the control of the tip temperature or the use of the instrument in endodontic This investigation determined the maximum tip temperatures corresponding to each power setting of the instrument and determined the power setting which would provide the same temperature distribution patterns as those produced with a Schilder OOP heat carrier during the vertical compaction of warm gutta percha. A type K thermocouple was welded to the tip of the Touch 'N Heat Model 5001 probe tip and connected to a Fluke 2240-A recording instrument. The maximum temperature and performance curve were determined for each power setting. The thermocouple monitoring of temperatures within an obturated root canal was done to evaluate the temperature distribution patterns created with the Schilder OOP heat carrier and the Touch 'N Heat Model 5001 on various power settings. The temperature elevations resulting after multiple simulated two minute compaction procedures were used to determine the power setting of the Touch 'N Heat which duplicated the thermoprofile created with a Schilder OOP heat carrier. The results show that the Touch 'N Heat performs rapidly and allows accurate control of the heat probe tip temperatures. The maximum tip temperatures ranged from 32°c (setting #1) to 732°c (setting #10). A comparison of thermoprofiles produced with the Schilder heat carrier and Touch 1 N Heat Model 5001 indicate that power setting #3.5 and a three second penetration time provide nearly identical temperature distribution patterns as a Schilder heat carrier. The maximum temperature of the probe tip at power setting #3.5 is 330°c, approximately 500°c below the temperature of a "cherry red" Schilder heat carrier. Additional observations in this study reveal the poor thermal conductivity of gutta percha as well as the high thermal conductivity of the Schilder pluggers. It is anticipated that conclusions derived from the acquired data will assist endodontists understanding of the vertical compaction of warm gutta percha.
Efficacy of a new papilla generation technique in implantology:
(Boston University, 2004) Shahidi, Peyman
Thirty-three patients with 67 implants were recruited for a prospective randomized controlled blinded study to compare the efficacy of a new uncovering technique with the conventional uncovering technique for papilla generation between implants and between an implant and an adjacent tooth. Patients were randomly distributed in a test and control group, and also were randomly assigned to two periodontal residents. Resident #1 was the inventor of the technique and Resident #2 had been trained in this technique. The residents measured the baseline thickness of the tissue covering the implant before and following the uncovering technique, along with the height of the papilla. The Pocketing probing depth, Plaque Index, Gingival Index, Bleeding Of Probing were measured at 0 and 6 months, and standardized reproducible radiographs were taken at 0, 3 and 6 months. A faculty member who was blinded to the study measured the height of each papilla at 3 and 6 months. Statistical analysis revealed a consistency between the 0, 3, and 6 month measurements. Hence the baseline data was included for a better evaluation. The mean difference between two surgical methods in favor of the new technique was over 1.5 mm in all three visits and statistically was highly significant. The mean difference between the two groups for papilla height between implant and tooth was 1.41mm (P=0.001), 1.76mm (P[less than]0.001), 1.71mm (P[less than]0.001) at 0, 3 and 6 months respectively. An overall significant difference in papillae height between the two groups was detected for implants adjacent to teeth (p=0.0003). However, no change in papillae height was detected over time (p=0.856) or by either group over time (p=0.788). The mean difference between the two groups for papilla height between implants was 1.14 mm (P[less than]0.018), 1.11 mm (P[less than]0.012), 0 .78 mm (P[less than]0.138) at 0, 3 and 6 months. An overall significant difference for papilla height between the implants was detected between the two groups (p=0.020). However, the alteration in papilla height between adjacent implants over time did not achieve statistical significance (p=0.062). There was no significant difference in PPD, PI, GI, BOP and in the thickness of the soft tissue covering the implant between the two groups. No statistical difference was found on the overall bone level between two groups at 3 months (P[less than]0.185) and 6 months (P[less than]0.911). In conclusion, a highly significant difference of papilla height was found between test and control groups, with the test group having greater papilla height than the control group. This is the first study that provides data comparing the papilla regeneration between implant and adjacent tooth and between two adjacent implants.
Examiner inconsistency in replicate radiographic interpretation as related to the effect of a caries inhibiting agent
(Boston University, 1970) Schuster, Steven Joel
An in-vitro assessment of fracture resistance of five porcelain crown systems
(Boston University, 1986) Rodrigues, Antonio H C
A total of forty five crowns of five different porcelain systems (Porcelain-fused-to-metal, Porcelain jacket, Dicor, Cerestore and Renaissance) were fabricated to uniform dimension and shape on identical metal dies by different sources (Manufacturers, commercial laboratories, and investigator). The crowns were permanently cemented to their dies and subjected to shear forces directed at a 130 degree angle to their incisal edge in an Instron testing machine. The fracture patterns were observed microscopically. Mean fracturing loads for the five different crowns systems were calculated and compared. The recorded mean fracture loads (in lbs) were: Group 1 (porcelain-fused-to-metal fabricated by manufacturer), 132 ±5; Group 2 (porcelain jacket fabricated by commercial laboratory), 42 ±4; Group 3 (Dicor crowns fabricated by commercial laborato ry), 79 ±5; Group 4 (Dicor crowns fabricated by manufacturer), 87 ±9; Group 5 (Dicor crowns at 1.5mm thickness fabricated by manufacturer), 98 ±6; manufacturer), 92 ±4; Group 6 (Cerestore crowns fabricated by Group 7 (Cerestore crowns fabricated by investigator), 68 ±15; group 8 (Renaissance crowns fabricated by manufacturer), 60 ±7; and Group 9 (Renaissance crowns fabricated by investigator), 27 ±4; The normal ranking of the results (i.e. p.f.m.- strong, p.j. - weak) and the fine discrimination between similar groups suggest that this testing modality has merit.
A retrospective analysis of bone and its relationship to implant success and patients' age
(Boston University, 2004) Pourati, Jacob A.
Implants have been overwhelmingly successful. After the first series of implant follow-up studies in the early 1980's, a trend was noticed with implant failure that was directly related to the bone density of future implant site (FIS). For this reason Lekholm and Zarb (L&Z) as well as their colleagues created new bone quality classifications to accommodate the implant treatment plan. After the introduction of the CT-scan, advances in bone augmentation techniques, implant surface modifications, a better understanding of implant force distribution and the effect of age on bone density, the relationship between bone quality and implant retention has become a more controversial topic. This research study will attempt to answer some of those preliminary questions about bone density and its effect on implant retention using a retrospective chart and CT-scan analysis of patients treated with implants using multiple methods to determine bone quality. The following topics are reviewed in this study. (1) Evaluate bone quality of FIS using Lekholm and Zarb technique and Quantitative CT (QCT) and its affect on implant retention. (2) Relation between 3 age groups' (17-50, 51-65, 65-85) bone quality and implant success. (3) Systemic influence, such as diabetes and smoking habits, on implant retention. MATERIAL AND METHODS: In this retrospective IRB reviewed and accepted research study, 73 implant patients of Boston University Goldman School of Dental Medicine (BUGSDM) Center of lmplantology from the time period 1999-2002 with available references were evaluated. The preoperative CT-scan of FIS of these patients with undisturbed bone (virgin bone) were evaluated for average cortical thickness, cancellous density measured in Houndsfield Units (HU), cancellous volume percent, quality of the bone inside the projected implant site or inside of the implant (HU), quality of the bone surrounding 1mm of the projected implant site (HU) or outside of the implant and also evaluated using the Lekholm and Zarb classification. Other implant sites that were done with bone modifying procedures were also documented to achieve a statistically larger population to evaluate the affects of age, smoking and diabetes on long-term implant retention. Patients received either 3i (West Palm Beach, Florida) or Zimmer implant system and were allowed a 4-6 months healing period before loading. Patient's charts were followed up to 24 months. RESULTS: Seventy-three patients (31.5 % of the total patients evaluated) were eligible to be used for the bone analysis portion of this research. This allowed 137 implants in our bone analysis study with 6 reported failures, all reported as early failures. Due to the fact that this is a retrospective chart review, the follow up period varied among the implants from the time of loading to more than 24 months. The original population of 73 patients with 137 implants was evaluated for Lekholm and Zarb bone classification, QCT bone variables described in this study and their affects on implant retention. The results indicated that the Lekholm and Zarb classification (Dl-D4) (analyzed by one calibrated study personnel) correlated with statistical significant with the QCT variables analyzed, and neither of these bone quality classifications and variables had correlation with the age of the patient or their respective implant retention. No statistical significant correlation was seen between the evaluated bone variables and implant outcome. Total patient population of 232 (538 implants with 20 reported failures), which included the original 73 patients and additional 159 patients who did not have a virgin bone site to allow them to qualify for the bone analysis, was divided into 3 age groups to evaluate the effects of age on implant retention. Group one (18-50) had 115 patients, group two (51-65) had 86 and group three (65-85) had 31 patients. With the whole population, the success rate of the implants was 93.7 percent. There was no statistical significance between patient age groups and implant success. Among the values evaluated in the patients, reported smoking habit (p value 0.03) and diabetes (p value 0.063) both had a significant impact on implant failure rate. Patients who are reported as smokers on their health questioner, had a 4.7 times increase in failure rate than reported non-smokers. Reported diabetic patients had similar failure odds ratio of 6.
A survey of level IV nursing home residents to assess dental care delivery preference
(Boston University, 1992) Plemmons, Linda C.
The over 65 year old population is growing rapidly. More people will be residing in long-term care facilities (LTCFs). Dental care delivery is needed to meet the increasing requirements of this population. The purpose of this research was to determine if elderly residents of rest, retirement, or Level IV nursing homes have a preference for on-site versus off-site dental care delivery. In Massachusetts, nursing homes, rest and retirement homes are equivalent because they provide residential as opposed to skilled nursing care due to the limited nursing needs of their residents. Fifty residents of Level IV LTCFs located in the greater Boston, Massachusetts area were selected for this study using an 11 question "Mini-Mental State" screening examination (MMS) and a 21 question survey. The survey included questions on perceived need for care, location where residents received that care, and preference for location of care. Data analysis included the generation of frequency distributions to determine subjects' preference for dental care delivery sites. The preference stated was for on-site delivery based upon reasons of convenience and lack of mobility. Of those residents who preferred on-site care, 83% resided in the facilities for more than two years. Familiarity with their dental staff, desire to maintain autonomy and the perception of greater professionalism were factors cited by the residents who preferred off-site care.
The human dentinal tubule and its associated odontoblast process : A scanning electron microscope study
(Boston University, 1985) Pannkuk, Terrell F.
The following study was designed to explore the controversy surrounding the nature of the contents of the human dentinal tubules. Freshly extracted human third molars were gathered and subjected to one of five techniques prior to examination with the scanning electron microscope. The results exemplified the effect of procedure variation upon the observed tubule con tents, artifacts, and the spatial arrangement of structures. The photomicrographs revealed tubule contents that were consistent with the odontoblast process, the hypomineralized lining of pertibular dentin, dendritic neuronal processes, and collagen; and these structures were evident through the entire thickness of dentin in the root and crown. Unusual "grape-like" clusters in the outer third of dentin were found to be consistent with vesicular outbudding of cell processes. Positive identification of tubular contents requires methodology different from that currently used in scanning electron microscopy.
An attitudinal survey assessing awareness, need, and interest toward dental implants in a population of senior adults
(Boston University, 1989) Pankowski, Nikki A.
An attitudinal survey on dental implants was conducted at two retirement communities in Rhode Island. Residents at the two communities were interviewed to determine their awareness of, possible need for, and interest in dental implants. Results indicated that seventy percent of the twentythree respondents were unaware of implants at the time of the interview. Fifty percent of the senior adults indicated a possible need for dental implants. Ninety-one percent of the respondents indicated an interest in implants by requesting additional information on implants. Forty-five percent indicated that they would consider receiving dental implants. However, advanced age was cited as the reason for a smaller percentage of the respondents considering receiving dental implants than those desiring additional information on implants.
The dolichol pathway of protein N-glycosylation: molecular genetics and functional significance
(Boston University, 1998) Lennon, Kelley L.
Protein N-glycosylation is metabolic process that is obligatory for viability in all eukaryotes. It results in the modification of appropriate asparagine residues of polypeptides with oligosaccharide structures, influencing their properties and bioactivities. N-glycosylation is initiated, via the dolichol pathway, with the synthesis of the lipid-linked oligosaccharide precursor that is later transferred to protein. This synthesis occurs in the endoplasmic reticulum and involves the expression of a set of evolutionarily conserved ALG genes. Contrary to the previous dogma, recent studies suggested that the early dolichol pathway genes are highly regulated, early growth response genes (Kukuruzinska and Lennon, 1994). RNA blotting assays presented here indicate that all the ALG genes, as well as two oligosaccharyltransferase (OT) subunits, are coordinately regulated with growth early in G1, at the GJG1 transition point. In contrast, at a second point in the cell cycle critical to proliferation, late in G1, the genes of the dolichol pathway and OT are differentially regulated. Specifically, ALG7 expression is selectively downregulated in response to cell cycle arrest. This proliferation dependent expression of the first dolichol pathway gene, ALG7, is also demonstrated in a higher vertebrate system, zebrafish, via immunohistochemistry and Western blotting. The mechanisms involved in the regulation of ALG7 expression in yeast were assessed with RNA blotting assays. Evidence is provided that this gene is controlled on transcriptional and post-transcriptional levels. Moreover, data from in vitro transcription/translation studies of the mammalian ALG7 gene suggest the possibility of additional control of this gene's expression, on the level of translation. Finally, the functional significance of the early dolichol pathway genes, and ALG7 in particular, is demonstrated through the use of disparate methodologies that include RNA blotting, flow cytometry, fluorescence and light microscopy. The results suggest that the early ALG genes have developmental relevance, since unwarranted changes in their expression cause defects in proliferation, differentiation and cytoskeletal organization. Moreover, these studies reveal potential downstream genetic targets for the ALG genes, and protein N-glycosylation in general, that include G1 cyclins and proteins involved in organization of the actin cytoskeleton.

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