Evaluating the impact sequences of operation have on the implementation of occupant-centric controls.

Partial occupancy of commercial offices has become the norm in the wake of the COVID-19 pandemic. Given this, occupant-centric control (OCC), which adapt building systems based on occupants' presence or preferences, offer an alternative to traditional control that assumes full occupancy. However, poor sequences of operation can degrade the benefits of OCC. This paper explores this interaction by examining energy data from two buildings - one with two control logic faults corrected and an occupancy-based ventilation OCC implemented in 2020, and one with traditional ventilation - from 2019 to 2020. Sequences that impacted implementation in the first building are discussed. Then, a calibrated energy model of the second building is developed to evaluate how occupancy-based ventilation alongside changes to the sequences of operation - namely supply air temperature (SAT) reset and economizer high limits - impacted energy use. The inclusion of OCC and improved sequences in the second building saved 30.6% and 9.6% of annual heating and cooling energy, respectively. Without an SAT reset, OCC saved 4.4% and 3.9% of heating and cooling, respectively, compared to 15.7% and 5.7% when an SAT was present. These results begin to characterize the relationship sequences of operation and OCC implementations have with one another in commercial offices.

The Effect of Plaster of Paris on Reliabilities of RUST and mRUST Scoring Systems.

PURPOSE OF THE STUDY The aim of our study is to investigate the reliabilities of the radiographic union score for tibial fracture (RUST) and modified RUST scoring systems in the evaluation of fracture healing in adult tibia fractures treated with intramedullary nailing and pediatric tibia fractures treated with closed reduction and cast immobilization and to compare the reliabilities between two groups. MATERIAL AND METHODS Between January 2016 and January 2020, the informations of patients (ages of 4-10) with tibia fractures treated with closed reduction and casting and patients (aged 18-65 years) with tibia fractures treated with intramedullary nailing were analyzed retrospectively. Forty-seven good quality AP and lateral radiographs (represent different healing stages) each for pediatric and adult fracture groups were selected and were included in two PPTs separately. The radiographs were assessed twice with an interval of three weeks by an observer group consisting of four senior orthopedic surgeons and four orthopedic residents, and fractures were evaluated according to the RUST and mRUST scoring systems. RESULTS The inter-observer agreement of RUST and mRUST were 'perfect' in adult tibia fractures and 'substantial' in pediatric tibia fractures in both evaluations. However, in deciding fracture consolidation, inter-observer agreement was found to be 'perfect' in pediatric tibia fractures, while it was 'substantial' in adult fractures in both assessments. The mean intra-observer reliability of RUST system in adult tibia fractures was 0.860 (0.674-0.968) and 0.818 (0.693-0.909) in pediatric tibia fractures, respectively. The mean intra-observer agreement of mRUST system was 0.842(0.745-0.979) in adult fractures and 0.857 (0.756-0.932) in pediatric fractures, respectively. The mean intra-observer reliability of decision on union was 0.842 (0.638-1.000) in adult fractures and 0.785 (0.611-0.977) in pediatric fractures, respectively. DISCUSSION The decision of union in tibia shaft fractures is based on repeated clinical and radiological evaluations but there are no universally accepted guidelines to evaluate radiographic union. It has been shown in previous studies that the RUST and mRUST scoring systems can be used safely in the evaluation of fracture healing in adult patients with tibia fracture treated with intra-medullary nailing. To our knowledge, there are no studies investigating the reliability of RUST and mRUST systems in conservatively treated pediatric tibial fractures. We hypothesized that the plaster of Paris makes it difficult to assess fracture union on direct radiographs and reduce the reliabilities of these scoring systems in pediatric tibial fractures. CONCLUSIONS Our study showed that both RUST and mRUST scoring systems are useful tools that can be used safely assessing fracture healing in both pediatric and adult tibia fractures. The presence of a plaster of Paris on the extremity did not adversely affect the inter-observer and intra-observer agreement of the RUST and mRUST scoring systems. Key words: pediatric tibia fracture, radiographic union score for tibial fracture (RUST), modified RUST, radiographic union, reliability.

A review of data collection and analysis requirements for certified green buildings.

While the research community widely recognizes the importance of post-occupancy measurement of buildings to verify performance, requirements of green building certification schemes are highly varied. To assess the effectiveness of building certification schemes during the operation and maintenance stage of certified buildings, this paper critically reviews recent case studies that report on post-certification performance. The review of relevant case studies from the literature reveals some important findings in relation to the performance gap of certified buildings. Subsequently, major operation and maintenance-related building certification schemes are surveyed to reveal the underlying reasons behind this performance gap. Post-certification actions that require post-occupancy data collection and analysis are identified through this survey and compared to highlight their strengths and shortcomings and pinpoint the major discrepancies in data infrastructure and archiving practices that hinder certified buildings in performing according to their design intent. Lastly, suggestions are extracted which may shed light on the re-certification pathways.

A prospective study of angle grinder injuries in the hands and forearms during a one-year period.

Angle grinders are powerful tools used for cutting, shaving and polishing metal, stone, concrete and many hard surfaces in the work and hobby context. The aim of this study was to evaluate the acute hand injuries caused by angle grinders and to identify risk factors. Out of 742 acute hand and forearm injuries presenting in our emergency department between March 2016 and March 2017, 82 cases of injury due to angle grinder were included in the study. The age, gender, occupation, experience and education level of the injured patients were recorded. In addition, the location, mechanism, time of day, cigarette or alcohol use and occupational cases were determined. The Modified Hand Injury Severity Score (MHISS) was used to determine the injury severity. The vast majority of injuries (except 8) were not occupational injuries. They often occurred when individuals were using this tool outside of a work context (home, etc.); 44% of the patients were retired. There were more injuries between the hours of 3 pm and 6 pm. The mean overall MHISS score of was 74 (2-330). These angle grinder injuries, many of which are severe, are difficult to treat and the resulting disability is high. Many factors, such as smoking, age and time of day contribute to these injuries. Precautions should be taken and safety training should be provided for this powerful tool which is widely used and easy to obtain.

Influence of fruit consumption and fluoride application on the prevalence of caries and erosion in vegetarians--a controlled clinical trial.

BACKGROUND/OBJECTIVES: Caries and erosion are common diseases of the dental hard tissues. The influence of vegetarianism on the development of caries and erosion has scarcely been investigated in the past. The aim of the present study was to evaluate the influence of fruit consumption and topical fluoride application on the prevalence of caries and erosion in vegetarians. SUBJECTS/METHODS: In 100 vegetarians and 100 nonvegetarians, a dental examination was performed. The indices for decayed, missing, filled teeth (DMFT) and surfaces (DMFS) were determined. DMFT and DMFS were subdivided into decayed teeth (DT), filled teeth (FT), decayed surfaces (DS) and filled surfaces (FS). In addition, the hygiene index and the number of teeth with dental erosion (DE), root caries (RC) and overhanging restoration margins (ORM) were recorded. A questionnaire assessed patients' eating habits, frequency of oral hygiene, dentist visits and topical fluoride application. For statistical analysis, unpaired t-test, Mann-Whitney test and Pearson's chi-square test were applied. RESULTS: Vegetarians had significantly more DT (P<0.001), DS (P<0.001), more teeth with DE (P=0.026), RC (P=0.002) and ORM (P<0.001) than nonvegetarians. Daily consumption of fruits was significantly more prevalent (P<0.001), and topical fluoride application was less prevalent (P<0.001) in vegetarians compared with nonvegetarians. In particular, fluoride-containing toothpaste (P<0.001) and table salt (P=0.039) were less frequently used in vegetarians. CONCLUSION: The presented data suggest that vegetarians have an increased risk for caries and erosion. Topical fluoride application was shown to be effective in preventing caries, but not in preventing erosion.

Periodontal conditions in vegetarians: a clinical study.

BACKGROUND/OBJECTIVES: Investigations about possible correlations between vegetarian diet and periodontal conditions are rare and characterized by small case numbers. The aim of this clinical study was to investigate the influence of a vegetarian diet on periodontal parameters with an appropriate sample size. SUBJECTS/METHODS: A total of 200 patients, 100 vegetarians and 100 non-vegetarians, were included in the study. All patients were examined including a full mouth assessment of the periodontal and dental conditions. In addition, a questionnaire was handed out to ask for patients' oral hygiene habits and level of education. For statistical analysis the Mann-Whitney Test (χ(2) for analysis of the questionnaire) was applied (level of significance: P<0.05). RESULTS: Well known periodontal risk factors like age, gender and smoking habits were equally distributed within each group (71 females, 29 males, respectively and 10 smokers in each group; mean age: 41.45 years vegetarians versus 41.72 years non-vegetarians). Vegetarians had significantly lower probing pocket depths (P=0.039), bleeding on probing (P=0.001), periodontal screening index (P=0.012), a better hygiene index (P<0.001) and less mobile teeth (P=0.013). Dental examinations revealed significantly less missing teeth (P=0.018) but also more decayed (P=0.001) and eroded (P=0.026) teeth in vegetarians. Furthermore, vegetarians had a higher level of education (P<0.001), but visited dentists significantly less frequent. CONCLUSIONS: Vegetarians revealed better periodontal conditions (less inflammation signs, less periodontal damage and a better dental home care). However, it should be considered that vegetarians are not only avoiding meat in their nutrition but are also characterized by an overall healthier life style.

Simulating waste temperatures in an operating landfill in Québec, Canada.

A bioreactor landfill operated in Sainte-Sophie, Québec, Canada was instrumented to better understand the waste stabilization process in northern climates. Instrument bundles were placed within the waste to monitor temperature, oxygen, moisture content, settlement, total load, mounding of leachate and electrical conductivity. A finite element model was developed to simulate the heat fluxes to and from the waste, as well as heat generation within the waste from both anaerobic and aerobic processes. The results of the analysis suggest the majority of the aerobic activity occurs in the top portion of the waste lift exposed to ambient air. In addition, the model indicates that frozen waste lifts require a significant amount of heat to thaw the liquid fraction. The model also demonstrates that when a lift of cold waste is placed at the bottom of the landfill, the subsurface acts as a significant source of heat.

Heat budget for a waste lift placed under freezing conditions at a landfill operated in a northern climate.

A landfill operated in Ste. Sophie, Québec, Canada was instrumented to better understand the waste stabilization process in northern climates. Instrument bundles were placed within the waste to monitor temperature, settlement, oxygen, moisture content, total load, mounding of leachate and electrical conductivity. A finite element model was developed to simulate the heat budget for the first waste lift placed in the winter months and was calibrated using the first 10.5 months of collected temperature data. The calibrated model was then used to complete a sensitivity analysis for the various parameters that impact the heat budget. The results of the analysis indicated that the heat required for phase change to thaw the liquid fraction within frozen waste had a significant impact on the heat budget causing sections of waste to remain frozen throughout the simulation period. This was supported by the data collected to date at Ste. Sophie and by other researchers indicating that frozen waste placed during the winter months can remain frozen for periods in access of 1.5 years.

Conservative treatment of periodontal recessions with class v-defects using gingiva-shaded composite--a systematic treatment concept.

Periodontal recessions can cause aesthetic and functional problems, especially in the anterior region or when combined with exposed crown margins. A combination of periodontal disease, recession with exposed root surface, hard-tissue defects and age emphasizes the need for treating these defects. If crown margins are exposed and surgical treatment is not possible, aesthetics and function can only be improved by replacement of the restoration. The restorative treatment option with a gingiva-shaded composite is especially valuable for dental fear patients or older patients with general or local risk factors, surgical contra-indications or Class III and IV recessions with questionable prognosis of surgery. The step-by-step-approach described in this article is an alternative, minimal-invasive treatment concept for cervical lesions in combination with all kinds of periodontal recessions, that is especially suitable for wedge-shaped defects next to exposed crown margins.

The effects of colloid pre-loading on thromboelastography prior to caesarean delivery: hydroxyethyl starch 130/0.4 versus succinylated gelatine.

This prospective, randomized, double-blind study compared the effects on thromboelastography (TEG) of pre-loading with two different colloid fluids prior to spinal anaesthesia for caesarean section. Healthy full-term parturients received either 500 ml 6% hydroxyethyl starch 130/0.4 (HES, n = 25) or 500 ml 4% succinylated gelatine (GEL, n = 25) prior to spinal anaesthesia. TEG parameters including reaction time (r-time), clot formation time (k-time), clot formation rate (α-angle) and maximum amplitude (MA) were measured immediately before and after pre-loading. Both groups had significantly shorter r-time and lower MA after pre-loading. The α-angle was significantly decreased after pre-loading with HES but not with GEL. No significant differences in k-time were induced pre-loading. In conclusion, pre-loading with HES or GEL was associated with a mild hypocoagulable effect in healthy parturients presenting for elective caesarean section; however, all TEG parameters in both groups remained within or very close to the normal range after pre-loading.

Shear bond strength of self-adhesive resins compared to resin cements with etch and rinse adhesives to enamel and dentin in vitro.

Self-adhesive resin cements should ease the placement of dental restorations. The purpose of this study was to evaluate their shear bond strength to enamel and dentin. Sixty molars were randomly assigned to 12 test groups (each n = 10), and the approximal surfaces were ground flat to get an enamel and dentin surface with a diameter of at least 4 mm. Ceramic specimens were bonded to the surfaces with either Variolink/Syntac Classic (VSC), Panavia F2.0 (PAF), RelyX Unicem (RLX), Maxcem Elite (MCE), iCem (IC), or an experimental self-adhesive resin cement (EXP). The shear bond strength (crosshead speed: 1 mm/min) was measured after 24-h storage in NaCl (37 degrees C). The fracture modes were determined with a stereomicroscope (magnification, 8-50-fold). VSC had the highest shear bond strength within the enamel groups (42.9 +/- 9 MPa) and IC the lowest (10.5 +/- 4.2 MPa, p < 0.001). The highest dentin shear bond strength was determined for VSC (39.2 +/- 8.9 MPa, p < 0.001) and the lowest for EXP (7.8 +/- 3.9 MPa, p < 0.001). Self-adhesive resin cements fractured mainly between resin and enamel or dentin. The shear bond strength of self-adhesive resin cements was inferior compared to conventional composite resin cements.

Highly concentrated EDTA gel improves cleaning efficiency of root canal preparation in vitro.

Debris and smear layer, as a product of mechanical root canal instrumentation, reduce the effectiveness of pharmacological substances to prevent post-treatment diseases and impair direct contact of filling materials with a clean dentinal surface. The aim of this in vitro study was to investigate the presence and localization of debris and smear layer via scanning electron microscope analysis after standardized root canal preparation with different chelating agents. Dentin surfaces received treatment with: (1) 15% ethylenediaminetetraacetic acid (EDTA), (2) 18.6% EDTA (3) and 24% EDTA or without any demineralizing chemicals as control. Forty vertically split human premolars were sputtered and divided into coronal, middle, and apical sections, followed by a randomized, blinded score evaluation using five scores. Pairwise comparisons of all treatment groups against a control group have been performed by Mann-Whitney U test and the Kruskal-Wallis test. Debris grades showed no significant difference between the three regions of the root canals, except for 18.6% EDTA in the central third. Smear layer and smear plug removal was concentration-dependent. Removal of the smear layer in the three areas showed that there was a statistically significant difference between all parts when using 18.6% and 24% EDTA concentrations compared with the control. The best smear layer removal in the apical region was observed using a 24% EDTA gel as chelating agent and lubricant. The usage of EDTA gel >/=18.6% presented a better cleaning regime when compared to the control group.

Effects of low-concentrated chlorhexidine on growth of Streptococcus sobrinus and primary human gingival fibroblasts.

The aim of this study was to investigate the in vitro effects of low concentrations of chlorhexidine (CHX) on the proliferation of Streptococcus sobrinus (ATCC 33478) and primary human gingival fibroblasts (HGF). Liquid cultures of bacteria or human gingival fibroblasts were exposed to CHX concentrations ranging from 0.07 to 40 microM in microtiter plates at 37 degrees C for 24 h. Bacteria or cells grown without CHX served as controls. The effects of CHX were determined either by measurements of the optical density (OD) of bacterial cultures or by evaluation of cell growth with the DNA-intercalating fluorescent stain H33342 in comparison to untreated controls. Results were evaluated calculating means and standard deviations. Data were statistically analyzed by an ANOVA using Post Hoc tests ( p<0.005). No growth inhibition of S. sobrinus was found at concentrations between 0.07 and 0.15 microM CHX, whereas 0.3 microM CHX led to an elongated (2 h more) lag phase and 0.6 microM CHX induced a lag phase of 4 h more and a minor inclination of the curve in the log phase. Concentrations of CHX>/=1.25 microM completely inhibited growth of S. sobrinus. On the contrary, CHX showed no significant effect on growth of HGF at concentrations

Chemical-biological interactions of NaF with three different cell lines and the caries pathogen Streptococcus sobrinus.

Fluoride is used in dentistry as a prophylactic agent to reduce caries rates due to the demineralization/remineralization effect and its influence on the metabolism of cariogenic bacteria. The purpose of this study was to evaluate the cytotoxic effects of sodium fluoride (NaF) on three different cell lines and the antibacterial potency on Streptococcus sobrinus. Cell lines were treated with various concentrations of NaF ranging from 0.039 mM to 10 mM for 24 h. For microbial assays, concentrations of NaF between 0.03 mM and 10 mM were added to liquid cultures of bacteria. Our results showed that immortalized human keratinocytes (HaCaT) and human osteogenic sarcoma cells (SAOS-2) were similarly affected by concentrations up to 2.5 mM. However, cell growth of HaCaT was slightly more inhibited at 2.5 mM of NaF than SAOS-2. At concentrations between 0.62 mM and 10 mM, 3T3 mouse fibroblast cells reacted more sensitively than HaCaT and SAOS-2 to NaF. The 3T3 cells did not survive in the presence of 10 mM NaF. NaF caused no significant effect on all tested cells at concentrations of < or = 0.31 mM. NaF at 0.039 mM and 0.06 mM did not affect growth of S. sobrinus. At concentrations of 0.125 mM and 0.5 mM, growth was slightly reduced. The proliferation of S. sobrinus significantly decreased at 1 mM and 2 mM NaF. S. sobrinus survived at 4 mM, revealing a delayed log phase with a decreased proliferation. No viable S. sobrinus cells were detected at concentrations of > or = 8 mM NaF. Data analysis revealed that overall treatment effects were highly significant (P<0.05, analysis of variance, Tukey's difference test). This study indicates that cytotoxic effects due to NaF significantly vary in dependence upon the applied cell line. The toxicity of NaF approached 50% (TC50) at concentrations of 6 mM for HaCaT, 2.3 mM for 3T3 cells, and 7.5 mM for SAOS-2. Additionally, NaF revealed antimicrobial effects only at concentrations that are significantly higher than oral fluoride concentrations.

Compatibility of resorbable and nonresorbable guided tissue regeneration membranes in cultures of primary human periodontal ligament fibroblasts and human osteoblast-like cells.

The purpose of this study was (a) to evaluate the cytocompatibility of three resorbable and nonresorbable membranes in fibroblast and osteoblast-like cell cultures and (b) to observe the growth of those cells on the various barriers by scanning electron microscopy (SEM). Primary human periodontal ligament fibroblasts (HPLF) and human osteoblast-like cells (SAOS-2) were incubated with nonresorbable polytetrafluoroethylene (ePTFE) barriers and resorbable polylactic acid as well as collagen membranes. Cytotoxic effects were determined by XTT (mitochondrial metabolic activity) and sulforhodamine B assays (cellular protein content). In addition, HPLF and SAOS-2 grown for 21 days on the investigated barriers were evaluated by SEM. Data were analyzed statistically by ANOVA using the Wilcoxon-Mann-Whitney test (P < 0.05). No changes were established in the periodontal ligament fibroblasts and human osteoblast-like cells after incubation with the collagen membrane. Cytotoxic effects, however, were induced by the polylactic acid barrier which slightly inhibited cell metabolism of the periodontal fibroblasts (XTT: 90.1% +/- 3.6 of control value). Moderate cytotoxic reactions were caused by the nonresorbable ePTFE membrane in HPLF-cultures (XTT: 82.7% +/- 3.5) and osteoblast-like cell monolayers (XTT: 80.0% +/- 0.6%). Mitochondrial activity in both cell cultures was significantly reduced by ePTFE barriers in comparison to non-incubated control cells (P = 0.028). SEM analysis of cell behavior on barriers demonstrated the differences between these materials: collagen barriers were densely populated with HPLF and SAOS-2, whereas only few or no cells were seen to adhere to the ePTFE and polylactic acid membranes. Our findings indicate that the collagen barrier investigated is very cytocompatible and may be integrated into connective tissue well. On the contrary, the ePTFE and polylactic acid membranes induced slight to moderate cytotoxic reactions which may reduce cellular adhesion. Thus, gap formation between the barrier surface and the connective tissue may be promoted which may facilitate epithelial downgrowth and microbial accumulation. Consequently, these effects may reduce the potential gain in periodontal attachment.

Placement of the preparation line and periodontal health--a prospective 2-year clinical study.

The aim of this prospective clinical 2-year study was to determine whether the placement of the proximal margins of crowns within the zone of the biologic width results in periodontal alterations. In 41 patients, 116 prepared teeth as well as 82 unrestored, healthy contralateral teeth were examined. The following indices were determined before as well as 3, 6, 12, and 24 months after preparation: hygiene index, papillary bleeding index (PBI), and probing depth. After preparation, the distance between the restoration margins and the alveolar crest was measured with a modified periodontal probe on both proximal aspects of each tooth. These values were classified into 3 groups: I = < or = 1 mm between crown margin and alveolar crest, II = 1 to 2 mm, and III = > 2 mm. In addition, radiographs were taken directly after cementation of each restoration and after 12 and 24 months. The hygiene index did not significantly vary during the investigation, but PBI increased in all groups. The highest PBI increase was found in group I; in this group, the most significant increase was found between 3 and 6 months after preparation. The mean probing depth only increased in group I during the first 3 months after preparation on the mesial aspects. Only minor changes were found on the distal aspects of the teeth in group I and on all aspects in groups II and III. No alterations of the bone levels were diagnosed on the radiographs. These results indicate that the location of the restoration margins within the zone of the biologic width may impair the periodontal health of restored teeth.

Cytocompatibility of periodontal dressing materials in fibroblast and primary human osteoblast-like cultures.

Purpose of this investigation was to determine the cytocompatibility of various periodontal dressing materials by means of human primary gingival fibroblasts (HGF), human osteoblast-like cells (HObl) derived from the alveolar bone, and permanent 3T3 mouse fibroblasts (3T3). Cell culture medium extracts (time periods of extraction: day 1 and between day 2 and day 8 after setting) as well as solid specimens of the following materials were investigated: Coe-pak, Voco pac, Peripac, and Barricaid. Responses of cultures exposed for 24 h and 48 h to these materials were monitored by the fluorescent dyes H33342 and sulforhodamin 101 as well as by light microscopy. It was found that most extracts of Voco pac, Peripac, and Barricaid did not inhibit growth of HGF. Coe-Pak, however, clearly reduced the proliferation of HGF compared to untreated controls. Peripac decreased growth of HObl whereas Coe-Pak, Voco pac, and Barricaid caused no cytotoxic alterations in any of the test assays. Contrary to HGF and HObl, 3T3 cells were much more irritated by the test materials. But the light-curing resinous material Barricaid reduced proliferation of 3T3-fibroblasts only slightly. Our data indicate that Barricaid is exceedingly cytocompatible, whereas all other materials revealed moderate or severe cytotoxic effects according to the cell type.

Nicotine-induced alterations in human primary periodontal ligament and gingiva fibroblast cultures.

Various in vivo and in vitro investigations have indicated that tobacco smoking as well as the use of smokeless tobacco products may be important risk factors for the development and severity of inflammatory periodontal disease. The purpose of this study was to determine the cytotoxicity of nicotine by means of human primary oral fibroblast cultures and a permanent cell line. The cytotoxicity of nicotine was evaluated by determination of cell growth, cell membrane integrity, protein content, and alterations of the cytoskeleton. Furthermore, recovery following nicotine exposure was assessed by vital staining (trypan blue). Dose-dependent toxic effects of nicotine were measured within a range of 0.48 mM to 62 mM. Growth of fibroblasts was decreased by nicotine concentrations higher than 7.8 mM. Additionally, the protein content was significantly decreased and cell membranes were damaged. Morphological alterations of microtubules and vimentin filaments were observed at concentrations higher than 3.9 mM. Nicotine-exposed cells revealed atypical shapes and vacuoles. The toxic effects of nicotine became irreversible in the range between 10.5 and 15.5 mM, whereas at lower concentrations cells recovered after the withdrawal of nicotine. Our results confirm clinical oberservations regarding the important role of nicotine as a risk factor in the etiology and progression of periodontal disease.

Effect on caries experience of a long-term preventive program for mothers and children starting during pregnancy.

The aim of this three-phase prospective study was to determine the effects of a primary-primary prevention program on the oral health of children. Eighty-six pregnant women from various social backgrounds participated in the first phase of this study. In the second phase (at 3 years of age) 54 of the mother-child couples and in the third phase (at 4 years of age) 47 of the mother-child couples remained. Participants were recalled every 6 months and received individual prophylactic care. The following clinical parameters were assessed at each examination period for mother and child: DMF-S or dmf-s, proximal plaque index, and the salivary level of Streptococcus mutans (Dentocult SM). The control group consisted of 65 (at 3 years of age) and 45 (at 4 years of age) children from various kindergartens. All children in the second phase of the study group revealed a naturally healthy dentition with an API of 0-25% and a salivary S. mutans score of 0 (0-10(3) cfu/ml). In the third phase, only four of the 47 children of the study group showed caries, with a mean dmf-s of 1.5. No S. mutans could be detected in 20 (42.6%) children. Ten (21.3%) children of the study group showed a S. mutans score of > or = 2 (> 10(5) cfu/ml). In contrast, only 53 of the 65 children of the control group (second phase) and 26 of the 45 control children (third phase) revealed a naturally healthy dentition. The remaining 19 children of the control group revealed a mean dmf-s of 7.0 at 4 years of age. In the control group, no S. mutans could be detected in 25 (38.5%) children at 3 years of age whereas 21 (32.3%) children showed a S. mutans score of > or = 2. In the third phase, a salivary S. mutans score of > or = 2 was found in 27 (60%) children of the control group. The statistical comparison between the study and the control groups revealed significant differences for all results determined (P < 0.001). Additionally, all mothers revealed a significant improvement in oral health and a reduction of salivary S. mutans colonization. From our data we conclude that a pre- and postnatal prevention program (primary-primary vs primary prevention) may significantly improve the oral health of mother and child.