• 한국치위생학회지
• /
• 제18권5호
• /
• pp.821-830
• /
• 2018

Objectives: This study aimed to examine the factors that affect the school-based oral health education in adolescents. Methods: This study was analyzed using data from the Korea youth risk behavior web-based survey in 2017. A total of 62,276 adolescents participated. The collected data was analyzed using the chi-square test, and logistic regression using SPSS, version 21.0. Results: Among the general factors related to oral health education in schools, male students experienced 1.14 times more oral health education in schools compared to female students, and middle school students experienced 1.81 times more oral health education than other students (p<0.001). With respect to oral health status, the groups without tooth fractures, pain during mastication, or gum pain and bleeding experienced 1.18 times, 0.95 times, and 1.03 times more oral health education in schools, respectively, compared to the group with complaints (p<0.001)(p<0.05). With respect to oral heath behavior, the group that brushed after lunch 'sometimes' during the last seven days received 1.43 times more oral health education compared to the group that 'always'brushed after lunch. Conclusions: It is necessary to supplement, extend, and strengthen oral health education programs in schools as well as motivate and recognize such programs.

• Restorative Dentistry and Endodontics
• /
• 제17권2호
• /
• pp.383-397
• /
• 1992

The purpose of this study was to evaluate the influence of artificial saliva contamination on bonding of several dentin adhesives to dentin. Sixty - three human molar teeth extracted within a month were used. Each tooth was sectioned longitudinally in a buccolingual direction to obtain 126 specimens. These specimens were randomly divided into three groups and were treated by Scotchbond 2, Gluma and All bond. Each group was subdivided into three subgroups; normal group not contaminated with artificial saliva, contaminated with artificial saliva and dried group, and contaminated with artificial saliva and washed and dried group. Enamel/dentin bonding agent(Dental Adhesive of Scotchbond 2) was applied and light cured on the treated dentin surfaces. Thereafter P - 50 were cured on them, and specimens were stored in $37^{\circ}C$ artificial saliva for 24 hours before measuring shear bond strength. Shear bond strengths were determined using an universal testing machine with cross head speed 1mm/min and SEM examinations were conducted to evaluate the resin - dentin interface and degree of penetrating resin string into the dentinal tubules. The following results were obtained. 1. Normal groups not contaminated with artificial saliva showed greater shear bond strength than any other group contaminated with artificial saliva(P<0.01). 2. The shear bond strengths showed no significant difference between washed groups with distilled water and not washed groups after contamination with artificial saliva(P>0.05). 3. In normal groups, the shear bond strength of A group was significantly greater than in any other group(P<0.01). 4. In Sand G groups, fractures after shear bond strength tests occured adhesively on resintooth interface in all specimens. But in A groups, fracture of the normal group occured cohesively in dentin and fracture of the contaminated groups occured adhesively and cohesively. 5. On SEM examination, the number of resin strings penetrated into dentinal tubules were the greatest in normal groups, followed by, in descending order, washed groups and not washed groups after contamination with artificial saliva.

• The Journal of Advanced Prosthodontics
• /
• 제7권2호
• /
• pp.160-165
• /
• 2015

PURPOSE. In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. MATERIALS AND METHODS. Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous$^{(R)}$; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at $30^{\circ}$ in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%. RESULTS. Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes. CONCLUSION. Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants.

• Restorative Dentistry and Endodontics
• /
• 제23권1호
• /
• pp.487-501
• /
• 1998

In the case of CAD/CAM ceramic inlay restorations, if isthmus width is widened too much, it may cause fracture of remaining tooth structure or loss of bonding at the luting interface because of excessive displacement of buccal or lingual cusps under occlusal loads. So to clarify the criterior of widening isthmus width, this study was designed to test the tensile bond strength and bond failure mode between dentin and ceramic cemented with luting composite resin cements. Cylindrical ceramic blocks(Vita Cerec Mark II, d=4mm) were bonded to buccal dentin of 40 freshly extracted third molars with 4 luting composite resin cements(group1 : Scotchbond Resin Cement/Scotchbond Multi-Purpose, group2 : Duolink Resin Cement/ All-Bond 2, group3: Bistite Resin Cement/Ceramics Primer, and group4:Superbond C&B). Tensile bond test was done under universal testing machine using bonding and measuring alignment blocks(${\phi}ilo$ & Urn, 1992). After immersion of fractured samples into 1 % methylene blue for 24 hours, failure mode was analysed under stereomicroscope and SEM. Results: The tensile bond strength of goup 1, 2 & 4 was $13.97{\pm}2.90$ MPa, $16.49{\pm}3.90$ MPa and $16.l7{\pm}4.32$ MPa, respectively. There was no statistical differences(p>0.05). But, group 3 showed significantly lower bond stregnth($5.98{\pm}1.l7$ MPa, p<0.05). In almost all samples, adhesive fractures between dentin and resin cements were observed. But, in group 1, 2 & 4, as bond strength increased, cohesive fracture within resin cement was observed simultaneously. And, in group 3, as bond strength decreased, cohesive fracture between hybrid layer and composite resin cement was also observed. Cohesive fracture within dentin and porcelain adhesive fracture were not observed. In conclusion, although adhesive cements were used in CAD/CAM -fabricated ceramic inlay restorations, the conservative priciples of cavity preparation must be obligated.

• Restorative Dentistry and Endodontics
• /
• 제48권2호
• /
• pp.16.1-16.11
• /
• 2023

Objectives: The aim of this study was to evaluate the influence of peak kilovoltage (kVp) and a metal artifact reduction (MAR) tool on image quality and the diagnosis of vertical root fracture (VRF) in cone-beam computed tomography (CBCT). Materials and Methods: Twenty single-rooted human teeth filled with an intracanal metal post were divided into 2 groups: control (n = 10) and VRF (n = 10). Each tooth was placed into the socket of a dry mandible, and CBCT scans were acquired using a Picasso Trio varying the kVp (70, 80, 90, or 99), and the use of MAR (with or without). The examinations were assessed by 5 examiners for the diagnosis of VRF using a 5-point scale. A subjective evaluation of the expression of artifacts was done by comparing random axial images of the studied protocols. The results of the diagnoses were analyzed using 2-way analysis of variance and the Tukey post hoc test, the subjective evaluations were compared using the Friedman test, and intra-examiner reproducibility was evaluated using the weighted kappa test (α = 5%). Results: The kVp and MAR did not influence the diagnosis of VRF (p > 0.05). According to the subjective classification, the 99 kVp protocol with MAR demonstrated the least expression of artifacts, while the 70 kVp protocol without MAR led to the most artifacts. Conclusions: Protocols with higher kVp combined with MAR improved the image quality of CBCT examinations. However, those factors did not lead to an improvement in the diagnosis of VRF.

• Restorative Dentistry and Endodontics
• /
• 제48권2호
• /
• pp.21.1-21.15
• /
• 2023

Objectives: This study evaluated the effects of Biodentine (BD), Bio-C Repair (BCR), and mineral trioxide aggregate (MTA) plug on the fracture resistance of simulated immature teeth with replacement root resorption (RRR) and in vitro-induced osteoclastogenesis. Materials and Methods: Sixty bovine incisors simulating immature teeth and RRR were divided into 5 groups: BD and BCR groups, with samples completely filled with the respective materials; MTA group, which utilized a 3-mm apical MTA plug; RRR group, which received no root canal filling; and normal periodontal ligament (PL) group, which had no RRR and no root canal filling. All the teeth underwent cycling loading, and compression strength testing was performed using a universal testing machine. RAW 264.7 macrophages were treated with 1:16 extracts of BD, BCR, and MTA containing receptor activator of nuclear factor-kappa B ligand (RANKL) for 5 days. RANKL-induced osteoclast differentiation was assessed by staining with tartrate-resistant acid phosphatase. The fracture load and osteoclast number were analyzed using 1-way ANOVA and Tukey's test (α = 0.05). Results: No significant difference in fracture resistance was observed among the groups (p > 0.05). All materials similarly inhibited osteoclastogenesis (p > 0.05), except for BCR, which led to a lower percentage of osteoclasts than did MTA (p < 0.0001). Conclusions: The treatment options for non-vital immature teeth with RRR did not strengthen the teeth and promoted a similar resistance to fractures in all cases. BD, MTA, and BCR showed inhibitory effects on osteoclast differentiation, with BCR yielding improved results compared to the other materials.

• 구강회복응용과학지
• /
• 제25권2호
• /
• pp.139-155
• /
• 2009

연구목적: 원추형(Superline) 임플란트를 발치와에 1회법으로 즉시 식립한 후 주변 조직의 생물학적 안정성을 관찰하는 것이다. 연구 방법: 치근부에 명백한 병적 소견이 있는 경우는 제외한 기타 치아의 발치와에 원추형 임플란트를 즉시 식립한다. 1회법을 식립한 후 임플란트 주변 연조직의 치유를 도모한다. 수술 후 32주에 획득한 표준화된 방사선상에서, 임플란트 주변골의 변화(depth of the distance from the implant shoulder (IS) and from the alveolar crest (AC) to the bottom of the defect (BD)) 등을 관찰했다. 결과 : 13명의 피검자 (남자 10명/ 여자 3명)를 선별하여 15개의 원추형 임플란트를 발치와에 즉시 식힙하였으며 모든 임플란트의 초기 고정은 양호했다. 평균 수술시간은 $41{\pm}10.0$분이었다. 모든 임플란트survival rate 는100% 였다. Mean ISQ values 는 상대적으로 안정했으며, 술 후 32주까지 계속 관찰에, 임플란트 인접 치조골 감소량은 $1.69{\pm}1.2mm$ (mesial), $1.65{\pm}1.2mm$ (distal) 로 나타났다. FMPS, FMBS, PPD와 각 은의 폭의 유의한 변화는 없었다. 결론: 파절이나, 근관치료의 실패 등의 이유로 해서 치아를 발치할 경우 치근형 (Superline)임플란트를 발칭하에 1회법으로 즉시 식립하는 술식은 임상적으로 예지성있는 치료법으로 판단된다.

• 대한치과교정학회지
• /
• 제12권2호
• /
• pp.145-154
• /
• 1982

Plaster models were constructed and orthopantomographs were taken for 86 male and 70 female primary school pupils, whose upper and lower permanent 4 incisors and 1st molars were completely erupted without crowding; whose deciduous canines and molars were found almost uniformly even without any visible tooth fractures, dental caries or restorations on proximal surfaces of the teeth. Certain reference points on the orthophantomograph were set up and measured and the values were compared with actual or predicted values from the models. The following results were obtained: 1. In regards to available space, the values from the orthopantomograph were greater than the values from the models by a mean of 3.24% on the upper and 10.06% on the lower for males; 3.05% on the upper and 10.01% on the lower for females. 2. In regards to total mesiodistal widths of permanent canine, 1st and 2nd premolars, the values from the orthopantomograph were greater than the presumed values based on the size of lower permanent 4 incisors from the models by a mean of 18.50% on the upper and 24.09% on the lower for males; 14.54 on the upper and 20.51% on the lower for females. 3. Comparing the magnified values of total mesiodistal widths of permanent canine, 1st and 2nd premolars with those of available space, the regression constants of regression equation (Y = a + bX) between them were a=3.2336, b=0.6533 on the upper and a=5.0138, b=0.3290 on the lower for males; a=2.5994, b=0.6521 on the upper and a=3.0113, b=0.6586 on the lower for females. 4. The correlation coefficients between the magnified values of available space and permanent canine, 1st and 2nd premolars were moderately positive as 0.6474 in the upper and 0.505 on the lower for males; 0.6493 on the upper and 0.6183 on the lower for females. 5. In regards to magnified values of the available space from the orthopantomographs there were no significant difference between sexes, (P>0.05) but of the total mesiodistal widths of permanent canine, 1st and 2nd premolars, a significant difference between sexes was found.(p<0.01).

• 대한치과보철학회지
• /
• 제40권6호
• /
• pp.545-559
• /
• 2002

There has been increasing use of IPS Empress $2^{(R)}$ owing to easy fabrication method, high esthetics similar to natural teeth, good marginal accuracy, and sufficient fracture strength. However, in clinical application, although a luting agent and the tooth cementation bonding procedure influence the marginal accuracy and fracture strength restoration, there has been a controversy in the selection of proper luting agent. This study was to measure the marginal fidelites and fracture strength of IPS Empress crowns according to three cement types, Protec $cem^{(R)}$, Variolink $II^{(R)}$ and Panavia $21^{(R)}$. After construction of 12 experimental dies for each group, IPS Empress $2^{(R)}$ crowns were fabricated and luted the metal master die prepartion of the maxillary right premolar. Marginal gaps before cementation and after cementation were measured. Buccal incline on the functional cusp of specimens were loaded until the catastrophic failure and fracture strength was measured. The results of this study were as follows: 1. The range of gap was $34.04{\pm}4.84{\mu}m$ before cementation and $37.88{\pm}5.00{\mu}m$ after cementation, which showed significant difference by paired t-test (p<0.05). The difference in the results from marginal accuracy according to measuring point proved to be not statistically significant by two-way ANOVA test (p>0.05). 2. The difference in the results from marginal accuracy according to three cement types Proved that The Variolink $II^{(R)}$ cement group had the least gap, $35.43{\pm}5.03{\mu}m$, and showed superior marginal accuracy while there existed statistic significance in Protec $cem^{(R)}$ cement group, $39.06{\pm}4.41{\mu}m$ or Panavia $21^{(R)}$ cement group, $39.16{\pm}4.39{\mu}m$ by two-way ANOVA test & multiple range test (p<0.05). 3. The difference in the results from fractures strength testing according to three cement type groups proved to be statistically significant (p<0.05). The Variolink $II^{(R)}$ cement group shows highest fracture strength of $1257.33{\pm}226.77N$, Panavia $21^{(R)}$ cement group has $1098.08{\pm}138.45N$, and Protec $cem^{(R)}$ cement group represents the lowest fracture strength of $926.75{\pm}115.75N$. 4. Three different cement groups of different components showed acceptable marginal fidelity and fracture strength. It is concluded that IPS Empress $2^{(R)}$ crowns luted using Variolink $II^{(R)}$ cement group had stronger fracture strength and smaller marginal gap than the other cement groups. Although Variolink $II^{(R)}$ resin cement seemed acceptable to clinical applications in IPS Empress $2^{(R)}$ system, the IPS Empress $2^{(R)}$ system still requires long-term research due to the lack of data in clinical applications.

• 대한소아치과학회지
• /
• 제28권4호
• /
• pp.654-660
• /
• 2001

상아질형성부전증은 유전적인 상아질의 결함으로 치아 발육과정 중 조직분화기에 발생되며 유치와 영구치 모두에서 나타난다. Shields등은 상아질형성부전증을 type I, II, III로 분류하였으며, Witkop에 따르면 1/8000명의 빈도로 이러한 유전적 소인을 갖게 되며, 남녀간의 차이는 뚜렷하지 않다고 한다. 이환받은 치아는 적갈색의 변색과 함께 심한 마모현상으로 인해 구치부 교합면과 전치의 절단면의 법랑질이 파괴되고 그후 급속도로 상아질의 파괴가 뒤따른다. 방사선학적으로 가느다란 치근과 구근상치관, 치경부 협착, 작거나 결손된 치수강이 관찰되고, 유치열에서 치근단병소나 다발성 치근파절이 관찰되기도 한다. 본 증례의 4세 남자환아는 치아색이 이상하다는 것을 주소로 연세대학교 치과병원 소아치과에 내원하였다. 치아는 전반적으로 황갈색의 변색과 중등도의 마모도를 보였으며, 방사선 검사 소견에서 치아의 치수강 폐쇄, 구근상치관, 짧은 치근들이 관찰되었다. 가족력상 각 세대마다 환아와 같은 치아변색과 마모의 유전양상이 관찰되었으며, 10세된 환아의누나는 영구치열에 전체적으로 회갈색의 변색과 경도의 마모도를 보였다. 임상 및, 방사선학적 검사소견상 상아질형성부전증으로 판단되어 환아의 손상된 치아에 대해 구치부는 기성금관 수복을, open-faced stainless steel crown으로 치근파절로 인해 발거된 상악 좌측 유중절치를 포함한 손상된 전치부를 수복해 기능적, 심미적으로 만족할 만한 결과를 얻어 이에 보고를 하는 바이다.