What do we know about mouthguards? (Report of the 1st International Sports Dentistry Workshop, 2016)

( Richard Leesungbok ),( Jeff Lloyd ),( Yoshinobu Maeda ),( Tomotaka Takeda ) 국제태권도학회 2017 International Symposium for Taekwondo Studies Vol.2017 No.-

Purpose: Our goal is to one day formulate consensus statements related to these questions, which will be based on current scientific evidence-based research, to motivate the international community of the importance of dentally fitted laminated mouthguards and the wearing of them by athletes of all sports. Methods: The 1st International Sports Dentistry Workshop took place in Honolulu, Hawaii, July 26-27, 2016. It was composed of sixteen sports dentists from Japan, Korea, Australia and the USA, who began their work months before the workshop by dividing up into four small groups and developing questions about their assigned topic. The topics were: ㆍ What do we know about mouthguards? ㆍ What do we know about mouthguards and impact force? ㆍ What do we know about mouthguards and performance enhancement? ㆍ What do we know about sports drinks and nutrition? The group searched the literature for current scientific evidence-based articles to try to find answers to questions that they had developed. The body of the work was then reviewed at the Hawaii workshop. Overall, the group shared the following concerns about some of the topics: ㆍ the age of the research could have been more current ㆍ there was a general lack of scientific evidence-based research ㆍ there were conflicting results from researchers on similar topics. It is the intention of the group to continue to meet and search for new scientific evidence-based literature so that consensus statements can eventually be formulated for these topics. Results: The purpose of the international sports dentistry workshop was to formulate and answer leading questions relevant to mouthguards and their use in sports. Dentally fitted laminated mouthguards worn on the upper jaw offer the best protection when compared with the “boil and bite” design in trauma prevention. Workshop collaboration in combination with scientific evidence suggests mouthguard design requires strict adherence to specific dimensions in order to reduce the effects of impact force. On the contrary, there was no difference in effectiveness of reducing impact force to the head with or without a mouthguard without clenching teeth. Mouthguards can attribute to enhancement of postural control and muscle performance during teeth clenching. Additionally, consumption of sports drinks prior to mouthguard use increases places athletes at a higher risk for dental caries. Conclusions: Collectively it was felt amongst all of the participants that more current research with more uniform controls (use of a dentally laminated mouthguard) would be most beneficial in the evaluation of more current scientific evidence based research and facilitate an international consensus statement regarding mouthguards that hopefully could promote more mandated usage internationally.

Specific Temporal Culturing and Microgroove Depth Influence Osteoblast Differentiation of Human Periodontal Ligament Cells Grown on Titanium Substrata

( Richard Leesungbok ),( Suk Won Lee ),( Su Jin Ahn ),( Kyung Hee Kim ),( Su Hee Jung ),( Soo Jeong Park ),( Do Yun Lee ),( Dae Hyeok Yang ),( Il Keun Kwon ) 한국조직공학·재생의학회 2012 조직공학과 재생의학 Vol.9 No.3

The purpose of this study is two-fold: to compare differences in the development of osteoblast differentiation processes between human bone marrow mesenchymal stem cells (MSCs) and human periodontal ligament cells (PLCs) cultured on microgrooved titanium (Ti) substrata and to investigate the effects of microgroove depth on PLCs` osteoblast differentiation. Using photolithography, 60 μm-wide and 10 or 20 μm-deep microgrooves were fabricated on the Ti substrata (NE60/10 or NE60/20). Subsequent acid etching was applied to the fabricated microgrooved Ti to yield the etched microgrooves (E60/10 and E60/20). Smooth and acid-etched Ti were used as the controls(NE0 and E0). Alkaline phosphatase activity and extracellular calcium deposition assays were performed after various timelines of culture on both MSCs and PLCs grown on NE0 and E60/10. For PLCs cultured on NE0, NE60/10, NE60/20, E0, E60/10 and E60/20, cell adhesion, cell proliferation, osteoblast differentiation were determined, followed by the analysis on various osteogenic gene expressions. By comparing the extracellular matrix maturation and mineralization processes on smooth and microgrooved Ti substrata, it was determined that PLCs require more time for osteoblast differentiation than MSCs. Also, E60/10 allowed for the highest levels of adhesion, proliferation, osteoblast differentiation, and osteogenic gene expression by PLCs. PLCs could be an excellent alternative to MSCs for use in future studies investigating cellular processes using microgrooved Ti substrata and other modified surfaces. Optimal Ti microgroove dimensions and osteogenic differentiation timelines are necessary to promote various cellular activities in human PLCs.

Clinical outcome of immediately and early loaded implants with laser treated surface: a 3-year retrospective study

Richard Leesungbok,Jin-Ho Seo,Sung-Am Cho 대한치과보철학회 2018 The Journal of Advanced Prosthodontics Vol.10 No.2

PURPOSE. The marginal bone loss of implants with laser treated surface was investigated after six weeks of loading after implant installation to the mandible molar area. MATERIALS AND METHODS. A total of 23 implants were placed in the edentulous molar area of the mandible: 13 implants were immediately loaded and 10 implants were early loaded. The implants used were made of titanium grade 23, screw shaped, 4.2 mm in diameter, and 10 mm in length. Patients were evaluated with resonance frequency analysis at implant fixture installation and 1, 2 (final prosthesis installation), 3, 5, 8, and 14 months later. X-rays were taken at 2 months after fixture installation and 1, 2, 3 years after to measure the marginal bone loss. RESULTS. The mean ISQ value measured at the implant installation was over 70 at all-time points. The average of marginal bone loss was average 0.33 mm. CONCLUSION. Immediate implant loading for laser treated implants would be possible.

보철 수복 후 임플란트 주위 병변에 대한 항목별 고찰

이성복(Richard Leesungbok),이석원(Suk-Won Lee) 대한치과의사협회 2021 대한치과의사협회지 Vol.59 No.11

Regardless of the type of implant, the loss of the implant crestal bone in the first year during post-implant-treatment and after functioning by prosthetic treatment is often greater than that of the following year. Possible causes for early implant bone loss include surgical trauma, occlusal overload, peri-implantitis, microgap, bio-logical width, and crest modules of the implant itself. Plaque index and Gingival index values were also found significantly higher for implants without KM(keratinized mucosa). KM of at least 2 mm should be maintained. Contour of implant restoration is known as one of the risk indicators of peri-implantitis. Prevalence of peri-implantitis was significantly greater in the bone-level group when the emergence angle was >30 degrees compared to an angle ≤30 degrees. Emergence angle of>30 degrees is a signific ianndti craistokr for peri-implantitis and convex profile creates an additional risk for bone-level implants, but not fo rtissuelevel implants. Biocom-patible materials should be used for all implant prosthetics, especially f otrhmeation of high polished surfaces with a reasonable appearance on the transmucosal part of the imp rlaensttorations. Bacterial products of the biofilm provoke an immune response in the gingival tissues. As btihoefilm matures-more complex inter-reactions occur and bacteria with more virulent qualities apprpoevaork,ing a more complex immune system response. Inflammation and immune response cannot be resolved until the bacteria biofilm is removed. To minimize the incidence of complications, dental professionals should make great effort in choosing reliable components and materials for implant-supported FDPs and the patients should be placed in well-structured maintenance system after treatment.

맞춤형 마우스가드의 효능과 실제

이성복(Richard Leesungbok) 대한치과의사협회 2015 대한치과의사협회지 Vol.53 No.9

The aim of this document is to evaluate the effect of bite balance on physical fitness and motor capacity to determine the importance of the occlusal stability as a possible action mechanism of occlusal appliance including mouthguards on physical performances. We all remember that day when the prominent athlete was in the news wearing a mouthguard to improve human athletic performance. I once had investigated the determinants of athletic performance in all sorts of sports. Most of the studies had overinterpretation of results and lack of evidence to support the information. However, I discovered great expectations for new possibility in this field and settled for a more academic approach to this intriguing subject. The followings are some examples of the subject 1. Archers who wore occlusal appliances to increase the vertical dimension of occlusion by 2~3mm increased their ability to focus and to maintain good sense of balance. Their accuracy rate has been improved. The appliance was made of acrylic resin (a type of plastic). 2. Canoe players who wore occlusal appliances to increase the vertical dimension of occlusion by 5mm surpassed longtime competitor and won the race with 10 seconds gap. 3. A cycle rider who wore an occlusal appliance to treat his malocclusion surpassed his old record from 10.8 seconds to 10.3 seconds. His muscle reflexes (anaerobic exercise) and endurance (aerobic exercise) has been enhanced. 4. Occlusal appliances had a good effect on athletic performance in most sports such as swimming, diving, and weightlifting. As for the clenching on dentition, people clench their teeth when they push their physical and mental limits during sports activities. Clenching can be induced by physical exertion when maximum muscle strength is retained and this is similarly found in different types of exercises. In addition, restraint of respiratory function is observed. Therefore, creating a occlusal balance with occlusal appliance or mouthguard promoted a favorable influence when an athlete clenches.

Effect of microgrooves and fibronectin conjugation on the osteoblast marker gene expression and differentiation

Park, Su-Jung,Leesungbok, Richard,Ahn, Su-Jin,Im, Byung-Jin,Lee, Do Yun,Jee, Yu-Jin,Yoon, Joon-Ho,Cui, Taixing,Lee, Sang Cheon,Lee, Suk Won The Korean Academy of Prosthodonitics 2015 The Journal of Advanced Prosthodontics Vol.7 No.6

PURPOSE. To determine the effect of fibronectin (FN)-conjugated, microgrooved titanium (Ti) on osteoblast differentiation and gene expression in human bone marrow-derived mesenchymal stem cells (MSCs). MATERIALS AND METHODS. Photolithography was used to fabricate the microgrooved Ti, and amine functionalization (silanization) was used to immobilize fibronectin on the titanium surfaces. Osteoblast differentiation and osteoblast marker gene expression were analyzed by means of alkaline phosphatase activity assay, extracellular calcium deposition assay, and quantitative real-time PCR. RESULTS. The conjugation of fibronectin on Ti significantly increased osteoblast differentiation in MSCs compared with non-conjugated Ti substrates. On the extracellular calcium deposition assays of MSCs at 21 days, an approximately two-fold increase in calcium concentration was observed on the etched 60-${\mu}m$-wide/10-${\mu}m$-deep microgrooved surface with fibronectin (E60/10FN) compared with the same surface without fibronectin (E60/10), and a more than four-fold increase in calcium concentration was observed on E60/10FN compared with the non-etched control (NE0) and etched control (E0) surfaces. Through a series of analyses to determine the expression of osteoblast marker genes, a significant increase in all the marker genes except type I collagen ${\alpha}1$ mRNA was seen with E60/10FN more than with any of the other groups, as compared with NE0. CONCLUSION. The FN-conjugated, microgrooved Ti substrate can provide an effective surface to promote osteoblast differentiation and osteoblast marker gene expression in MSCs.

Analysis of crown size and morphology, and gingival shape in the maxillary anterior dentition in Korean young adults

Jae-Won Song,Richard Leesungbok,Su-Jung Park,Se Hun Chang,Su-Jin Ahn,Suk-Won Lee 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.4

PURPOSE. The aim of this investigation was to analyze the dimensions of clinical crowns and to classify the crown and the gingival type in the anterior teeth in Korean young adults. MATERIALS AND METHODS. Casts were obtained from 50 subjects ranging in age from 24 to 32. Measurements of length and width were made on the casts using a pair of digital calipers on the entire dentition. Crown thickness and papilla height were also measured and MDW/CL (mesiodistal width to clinical length) and CW/CL (cervical width to clinical length) ratios of the maxillary anterior teeth were calculated. The K-clustering method was used for CW/CL to classify the anterior tooth shape into three groups (tapered, ovoid, and square), and one-way analysis of variance and Duncan’s post-hoc comparison were used to evaluate statistical significance between the groups. Pearson’s correlation analysis was performed between tooth shape and papillary height (PH) to demonstrate the correlation between tooth shape and gingival morphological characteristics. RESULTS. The average length of the maxillary central incisors was 9.89 mm; the mesio-distal width was 8.54 mm; and the ratio of width/length was 0.86 in Korean young adults. The average bucco-palatal thickness of the central incisor was 3.14 mm at the incisal 1/3 aspect. Ovoid type was the most common tooth shape (48%), followed by square type (29%) and taper type (23%) in the central incisors of Korean young adults. Tooth shape and gingival type were correlated with each other. CONCLUSION. New reference data were established for tooth size in Korean young adults and the data show several patterns of tooth shape and gingival type. Clinicians should diagnose and treat based on these characteristics for better results in the Korean population.

Analysis of dimensions and shapes of maxillary and mandibular dental arch in Korean young adults

Park, Su-Jung,Leesungbok, Richard,Song, Jae-Won,Chang, Se Hun,Lee, Suk-Won,Ahn, Su-Jin The Korean Academy of Prosthodonitics 2017 The Journal of Advanced Prosthodontics Vol.9 No.5

PURPOSE. The aim of this study was to investigate dental arch dimensions and to classify arch shape in Korean young adults. MATERIALS AND METHODS. The sample included 50 Koreans with age ranging from 24 to 32 years. Maxillary and mandibular casts were fabricated using irreversible hydrocolloid and type III dental stones. Incisor-canine distance, $incisor-1^{st}$ molar distance, $incisor-2^{nd}$ molar distance, intercanine distance, $inter-1^{st}$ molar distance, and $inter-2^{nd}$ molar distance in both the maxillary and mandibular arch were measured using a three-dimensional measuring device. The dental arch was classified into three groups using five ratios from the measured values by the K-means clustering method. The data were analyzed with one-way analysis of variance. RESULTS. Arch lengths (IM2D, $incisal-2^{nd}$ molar distance) were 44.13 mm in the maxilla and 40.40 mm in the mandible. Arch widths (M2W, inter $2^{nd}$ molar width) were 64.12 mm in the maxilla and 56.37 mm in the mandible. Distribution of the dental arch form was mostly ovoid shape (maxilla 52% and mandible 56%), followed by the V-shape and the U-shape. The arch width for the U-shape was broader than for the other forms. CONCLUSION. This study establishes new reference data for dental arch dimensions for young Korean adults. The most common arch form is the ovoid type in the maxilla and mandible of Koreans. Clinicians should be aware of these references and classify arch type before and during their dental treatment for effective and harmonized results in Koreans.

Effect of microgrooves and fibronectin conjugation on the osteoblast marker gene expression and differentiation

Su-Jung Park,Richard Leesungbok,Su-Jin Ahn,Byung-Jin Im,Do Yun Lee,Yu-Jin Jee,Joon-Ho Yoon,Taixing Cui,Sang Cheon Lee,Suk Won Lee 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.6

PURPOSE. To determine the effect of fibronectin (FN)-conjugated, microgrooved titanium (Ti) on osteoblast differentiation and gene expression in human bone marrow−derived mesenchymal stem cells (MSCs). MATERIALS AND METHODS. Photolithography was used to fabricate the microgrooved Ti, and amine functionalization (silanization) was used to immobilize fibronectin on the titanium surfaces. Osteoblast differentiation and osteoblast marker gene expression were analyzed by means of alkaline phosphatase activity assay, extracellular calcium deposition assay, and quantitative real-time PCR. RESULTS. The conjugation of fibronectin on Ti significantly increased osteoblast differentiation in MSCs compared with non-conjugated Ti substrates. On the extracellular calcium deposition assays of MSCs at 21 days, an approximately two-fold increase in calcium concentration was observed on the etched 60-μm-wide/10-μm-deep microgrooved surface with fibronectin (E60/10FN) compared with the same surface without fibronectin (E60/10), and a more than fourfoldincrease in calcium concentration was observed on E60/10FN compared with the non-etched control (NE0) and etched control (E0) surfaces. Through a series of analyses to determine the expression of osteoblast marker genes, a significant increase in all the marker genes except type I collagen α1 mRNA was seen with E60/10FN more than with any of the other groups, as compared with NE0. CONCLUSION. The FN-conjugated, microgrooved Ti substrate can provide an effective surface to promote osteoblast differentiation and osteoblast marker gene expression in MSCs.

Effect of etched microgrooves on hydrophilicity of titanium and osteoblast responses : A pilot study

Park, Jung-Ae,Leesungbok, Richard,Ahn, Su-Jin,Lee, Suk-Won 대한치과보철학회 2010 The Journal of Advanced Prosthodontics Vol.2 No.1

PURPOSE. The aim of this pilot study was to investigate the effect of etched microgrooves on the hydrophilicity of Ti and osteoblast responses. MATERIAL AND METHODS. Microgrooves were applied on Ti to have 15 and 60 μm width, and 3.5 and 10 μm depth by photolithography, respectively. Further acid etching was applied to create Ti surfaces with etched microgrooves. Both smooth- and acid-etched Ti were used as the controls. The hydrophilicity of Ti was analyzed by determining contact angles. Cell proliferation and osteogenic activity of MC3T3 mouse preosteoblasts were analyzed by bromodeoxyuridine assay and alkaline phosphatase (ALP) activity test, respectively. One-way ANOVA, Pearson&s correlation analysis and multiple regression analysis were used for statistics. RESULTS. Etched microgrooves significantly increased the hydrophilicity of Ti compared to the smooth Ti. 60 μm-wide etched microgrooves significantly enhanced cell proliferation, whereas the osteogenic activity showed statistically non-significant differences between groups. Result of the osteogenic activity significantly correlated with those of hydrophilicity and cell proliferation. Hydrophilicity was determined to be an influential factor on osteogenic activity. CONCLUSION. This study indicates that increase in hydrophilicity of Ti caused by etched microgrooves acts as an influential factor on osteogenic activity. However, statistically non-significant increase in the ALP activity suggests further investigation.