Evaluation of trueness in a denture base fabricated by using CAD-CAM systems and adaptation to the socketed surface of denture base: An in vitro study.

STATEMENT OF PROBLEM: Computer-aided design and computer-aided manufacturing (CAD-CAM) systems are increasingly used to fabricate removable complete dentures. However, comparisons and analyses of the trueness and adaptation of the socketed surface of denture bases produced by milling (MIL) and digital light processing (DLP) are lacking. PURPOSE: The purpose of this in vitro study was to evaluate and compare the trueness and socketed surface adaptation of denture bases fabricated by using additive and subtractive manufacturing. MATERIAL AND METHODS: Based on a denture base standard tessellation language (STL) file, a total of 15 denture bases were produced by using DLP (horizontal and vertical direction) and MIL. The intaglio and cameo surfaces of the fabricated denture bases were scanned with a dental scanner. The scanned intaglio and cameo surfaces were overlapped with the corresponding reference denture base STL file for trueness evaluation. In addition, the ridge lap STL file of the diagnostic tooth arrangement, in which reverse normal was performed, was superimposed on the socketed surface of the denture base of all groups to evaluate adaptation. RESULTS: The root mean square (RMS) values of trueness and adaptation showed statistically significant differences (P<.05). For the trueness RMS value of the intaglio surface of the denture base, the MIL-denture base (MDB) group had the lowest value of 150 ±6 µm, whereas the vertical denture base (VDB) of the DLP group was the largest with 328 ±4 µm. For the trueness RMS value of the cameo surface, the MDB group was the lowest with 50 ±1 µm, whereas the VDB group was the largest with 334 ±24 µm. For the adaptation RMS value of the socketed surface of the denture base, the MDB group was the lowest with 44 µm, whereas the VDB group was the largest with 117 ±2 µm. CONCLUSIONS: Within the limits of this in vitro study, the MDB group showed better trueness and socketed surface adaptation than the DLP groups (HDB and VDB).

Effect of layer thickness setting on the adaptation of stereolithography apparatus-fabricated metal frameworks for removable partial dentures: An in vitro study.

STATEMENT OF PROBLEM: A staircase effect is noted in the fabrication of metal frameworks for removable partial dentures (RPDs) when using stereolithography apparatus (SLA). It affects the adaptation of the definitive metal framework depending on the layer thickness setting. However, studies on the effect of the layer thickness setting on the adaptation of metal frameworks are lacking. PURPOSE: The purpose of this in vitro study was to determine the optimal layer thickness through comparative analysis of the adaptation of SLA-fabricated metal frameworks with different layer thickness settings. MATERIAL AND METHODS: A total of 15 metal RPD frameworks were SLA-fabricated by using 3 different layer thickness settings (16 µm, 50 µm, and 100 µm). The adaptation of the frameworks was measured by using the silicone replica technique, sectioned at the canine, first molar, and second molar regions by using a guide. The thickness of the light-body silicone was measured with a digital microscope at 3 points in each of the 3 areas. The measurements of the adaptation were statistically analyzed using the nonparametric Kruskal-Wallis test and post hoc Mann-Whitney U test with Bonferroni correction. RESULTS: The gaps measured in each area showed statistically significant differences in all 3 groups (P<.05). In the anterior, middle, and posterior areas, the 16-µm metal framework group showed the narrowest gaps (207 ±46 µm, 195 ±49 µm, and 188 ±40 µm, respectively). The 3 groups showed statistically significant differences in total gaps in the RPD frameworks relative to the layer thickness settings (P<.05); the total gap was lowest (197 ±42 µm) for the 16-µm group. CONCLUSIONS: For SLA, 50 µm is the recommended layer thickness considering the effect of layer thickness settings on the adaptation of the RPD framework and the fabrication time.

Mucilaginibacter aquaedulcis sp. nov., isolated from fresh water.

An aerobic, Gram-stain-negative, rod-shaped bacterium, designated strain PGW1-R01(T), was isolated from fresh water from the Yeongju in the Republic of Korea. The strain grew optimally at 30 °C and at pH 6-8 on R2A agar. The major cellular fatty acids were summed feature 3 [comprising C16 : 1ω7c and/or C16 : 1ω6c (50.2 %) and iso-C15 : 0 (24.8 %)]. The major respiratory quinone was MK-7. The G+C contents were 39.4 mol% and the predominant respiratory quinone was MK-7. Based on 16S rRNA gene phylogeny, the strain belongs to the genus Mucilaginibacter. The strain PGW1-R01(T) was closely related to 'Mucilaginibacter ginsenosidivorax' (96.6 % sequence similarity), Mucilaginibacter lappiensis (96.4 %) and Mucilaginibacter flavus (96.4 %). On the basis of the evidence presented in this study, strain PGW1-R01(T) represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter http://dx.doi.org/10.1601/nm.11437aquaedulcis sp. nov., is proposed. The type strain is PGW1-R01(T)( = KCTC 23942(T) = CECT 8102(T)).

Ferruginibacter yonginensis sp. nov., isolated from a mesotrophic artificial lake.

A Gram-stain-negative, rod-shaped, aerobic and reddish-pigmented strain, designated HME8442(T), was isolated from a mesotrophic artificial lake. The strain grew optimally at 30 °C and pH 7 on R2A agar. The major fatty acid was iso-C15 : 0. The polar lipids were phosphatidylethanolamine, one unidentified aminolipid and three unidentified polar lipids. The predominant respiratory quinone was MK-7. The DNA G+C content was 35.8 mol%. Strain HME8442(T) was closely related to Ferruginibacter lapsinanis HU1-HG42(T) (94.4 % 16S rRNA gene sequence similarity) and Ferruginibacter alkalilentus HU1-GD23(T) (93.9 %). The phylogenetic tree based on 16S rRNA gene sequences showed that strain HME8442(T) formed a lineage within the genus Ferruginibacter. On the basis of the evidence presented in this study, strain HME8442(T) represents a novel species of the genus Ferruginibacter, for which the name Ferruginibacter yonginensis sp. nov. is proposed. The type strain is HME8442(T) ( = KACC 17314(T) = CECT 8289(T)).

Sediminibacterium goheungense sp. nov., isolated from a freshwater reservoir.

A novel bacterial strain designated HME7863(T) was isolated from a freshwater reservoir in Goheung, Republic of Korea. Cells of strain HME7863(T) were Gram-staining-negative, strictly aerobic, orange-pigmented, rod-shaped and motile by gliding. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain HME7863(T) formed a lineage within the genus Sediminibacterium. Strain HME7863(T) was closely related to Sediminibacterium ginsengisoli DCY13(T) (96.9 % sequence similarity) and Sediminibacterium salmoneum NJ-44(T) (96.4 %). The major cellular fatty acids were iso-C15 : 1 G, iso-C15 : 0, iso-C17 : 0 3-OH and iso-C16 : 0 3-OH. Polar lipid analysis revealed the presence of phosphatidylethanolamine, five unidentified aminolipids, two unidentified aminophospholipids, one unidentified phospholipid and two unidentified polar lipids. The only respiratory quinone was MK-7. The DNA G+C content was 40.5 mol%. On the basis of the evidence presented in this study, strain HME7863(T) represents a novel species of the genus Sediminibacterium, for which the name Sediminibacterium goheungense sp. nov., is proposed. The type strain is HME7863(T) ( = KCTC 23945(T) = CECT 8100(T)).

Chitinimonas viridis sp. nov., isolated from a mesotrophic artificial lake.

A Gram-staining-negative, rod-shaped bacterium, strain HMD2169(T), was isolated from a mesotrophic artificial lake in Korea. Strain HMD2169(T) grew in the presence of 0-3.0% (w/v) NaCl, at pH 5-10 and at 20-37 °C. The predominant quinone of strain HMD2169(T) was ubiquinone (UQ)-8. The major fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, two unidentified aminolipids and two unidentified lipids. The DNA G+C content was 59.8 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMD2169(T) was a representative of a lineage within the genus Chitinimonas. Strain HMD2169(T) was closely related to Chitinimonas taiwanensis (95.8 % sequence similarity) and Chitinimonas koreensis (94.6 %). On the basis of the evidence presented in this study, strain HMD2169(T) is a representative of a novel species of the genus Chitinimonas, for which the name Chitinimonas viridis sp. nov. is proposed with the type strain HMD2169(T) ( = KCTC 22839(T) = CECT 7703(T)).

Mucilaginibacter soyangensis sp. nov., isolated from a lake.

A non-motile, yellow-orange-pigmented bacterial strain, designated HME6664(T), was isolated from Lake Soyang, Republic of Korea. The major fatty acids of strain HME6664(T) were summed feature 3 (comprising C16 : 1ω6c and/or C(16 : 1)ω7c; 44.7%) and iso-C15 : 0 (20.2%). The DNA G+C content was 40.8 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME6664(T) formed a lineage within the genus Mucilaginibacter. Strain HME6664(T) was closely related to Mucilaginibacter ximonensis (96.7%), Mucilaginibacter dorajii (96.5%) and Mucilaginibacter lappiensis (96.3%). On the basis of the evidence presented in this study, strain HME6664(T) represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter soyangensis sp. nov., is proposed. The type strain is HME6664(T) ( = KCTC 23261(T) = CECT 7824(T)).

Lacihabitans soyangensis gen. nov., sp. nov., a new member of the family Cytophagaceae, isolated from a freshwater reservoir.

A Gram-staining-negative, non-motile and orange-pigmented bacterium, designated strain HME6675(T), was isolated from freshwater of a reservoir in Korea. The major fatty acids of strain HME6675(T) were iso-C15 : 0 (33.4 %) and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c; 31.3 %). The major respiratory quinone was MK-7. The polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified aminophospholipid and three unidentified polar lipids. The DNA G+C content of strain HME6675(T) was 37.7 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME6675(T) formed a lineage within the family Cytophagaceae and was related to Leadbetterella byssophila 4M15(T) (93.0 % sequence similarity), Fluviimonas pallidilutea TQQ6(T) (90.6 %) and Emticicia oligotrophica GPTSA100-15(T) (89.1 %). On the basis of the evidence presented in this study, strain HME6675(T) represents a novel genus and species of the family Cytophagaceae, for which the name Lacihabitans soyangensis gen. nov., sp. nov. is proposed. The type strain of Lacihabitans soyangensis is HME6675(T) ( = KCTC 23259(T) = CECT 7826(T)).

Mucilaginibacter flavus sp. nov., isolated from wetland.

A non-motile, pale yellow, colony-forming strain, designated HME6839(T), was isolated from the wetland of Jeju Island, Republic of Korea. The major fatty acids of strain HME6839(T) were summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c), iso-C15 : 0 and C16 : 1ω5c. The DNA G+C content was 41.2 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HME6839(T) formed a lineage within the genus Mucilaginibacter. Strain HME6839 (T) [corrected] was closely related to Mucilaginibacter dorajii (96.7 %), Mucilaginibacter polysacchareus (96.5 %) and Mucilaginibacter lappiensis (96.3 %). On the basis of the chemotaxonomic and phylogenetic results presented in this study, strain HME6839(T) represents a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter flavus sp. nov., is proposed. The type strain is HME6839(T) ( = KCTC 23441(T) = CECT 7857(T)).

Effect of rinsing time on the accuracy of interim crowns fabricated by digital light processing: An in vitro study.

PURPOSE: This study was to evaluate the effect of rinsing time on the accuracy of interim crowns fabricated by digital light processing. MATERIALS AND METHODS: The maxillary right first molar master die was duplicated using a silicone material, while a study die was produced using epoxy resin. Scans of the epoxy resin die were used in combination with CAD software to design a maxillary right first molar interim crown. Based on this design, 24 interim crowns were fabricated with digital light processing. This study examined the trueness and precision of products that were processed with one of the three different postprocessing rinsing times (1 min, 5 min, and 10 min). Trueness was measured by superimposing reference data with scanned data from external, intaglio, and marginal surfaces. Precision was measured by superimposing the scan data within the group. The trueness and precision data were analyzed using Kruskal-Wallis, nonparametric, and post-hoc tests, and were compared using a Mann-Whitney U test with Bonferroni correction (α=.05). RESULTS: The trueness of the external and intaglio surfaces of crowns varied significantly among the different rinsing times (P =.004, P =.003), but there was no statistically significant difference in terms of trueness measurements of the marginal surfaces (P =.605). In terms of precision, statistically significant differences were found among the external, intaglio, and marginal surfaces (P =.001). CONCLUSION: Interim crowns rinsed for 10 minutes showed high accuracy.

Evaluating the accuracy (trueness and precision) of interim crowns manufactured using digital light processing according to post-curing time: An in vitro study.

PURPOSE: This study aimed to compare the accuracy (trueness and precision) of interim crowns fabricated using DLP (digital light processing) according to post-curing time. MATERIALS AND METHODS: A virtual stone study die of the upper right first molar was created using a dental laboratory scanner. After designing interim crowns on the virtual study die and saving them as Standard Triangulated Language files, 30 interim crowns were fabricated using a DLP-type 3D printer. Additively manufactured interim crowns were post-cured using three different time conditions-10-minute post-curing interim crown (10-MPCI), 20-minute post-curing interim crown (20-MPCI), and 30-minute post-curing interim crown (30-MPCI) (n = 10 per group). The scan data of the external and intaglio surfaces were overlapped with reference crown data, and trueness was measured using the best-fit alignment method. In the external and intaglio surface groups (n = 45 per group), precision was measured using a combination formula exclusive to scan data (10C2). Significant differences in accuracy (trueness and precision) data were analyzed using the Kruskal-Wallis H test, and post hoc analysis was performed using the Mann-Whitney U test with Bonferroni correction (α=.05). RESULTS: In the 10-MPCI, 20-MPCI, and 30-MPCI groups, there was a statistically significant difference in the accuracy of the external and intaglio surfaces (P <.05). On the external and intaglio surfaces, the root mean square (RMS) values of trueness and precision were the lowest in the 10-MPCI group. CONCLUSION: Interim crowns with 10-minute post-curing showed high accuracy.

Pedobacter soyangensis sp. nov., isolated from Lake Soyang in Korea.

Strain HME6451(T) was isolated from Lake Soyang in Korea. Phylogenetic tree based on 16S rRNA gene sequence showed that strain HME6451(T) formed a lineage within the genus Pedobacter. The strain HME6451(T) was closely related to Pedobacter daechungensis (95.4% sequence similarity), Pedobacter lentus (94.4%), and Pedobacter glucosidilyticus (93.8%). And strain HME6451(T) was a Gram-staining-negative, short rod-shaped, strictly aerobic bacterium. The major fatty acids were iso-C15:0 (41.2%), summed feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c; 23.1%), and iso-C17:0-3OH (10.1%). The polar lipids of HME6451(T) were consisted of one phosphatidylethanolamine, one unidentified aminolipid, one unidentified phospholipid and four unidentified polar lipids. The DNA G+C content was 36.0 mol%. On the basis of the evidence presented in this study, strain HME6451(T) represent a novel species of the genus Pedobacter, for which the name Pedobacter soyangensis sp. nov., is proposed the type strain HME6451(T) (=KCTC 23467(T) =CECT 7865(T)).

Pontibacter jeungdoensis sp. nov., isolated from a solar saltern in Korea.

A Gram-staining-negative, rod-shaped and red-pigmented bacterial strain, HMD3125(T), was isolated from a solar saltern in Jeungdo, Republic of Korea. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMD3125(T) formed a lineage within the genus Pontibacter and was similar to Pontibacter salisaro (96.1%) and P. korlensis (95.3%). The major fatty acids of strain HMD3125(T) were summed feature 4 (comprising iso-C17:1 I and/or anteiso-C17:1 B; 30.4%), iso-C15:0 (20.4%) and iso-C17:0 3OH (17.2%). The polar lipid profile of HMD3125(T) consisted of the phosphatidylethanolamine, four unidentified polar lipids, unidentified phospholipid, unidentified aminolipid and unidentified aminophospholipid. Strain HMD3125(T) contained MK-7 as the predominant menaquinone and sym-homospermidine as the major polyamine. The DNA G+C content of strain HMD3125(T) was 45.6 mol%. Strain HMD3125(T) assigned as a novel species in the genus Pontibacter, for which the name Pontibacter jeungdoensis sp. nov. is proposed. The type strain is HMD3125(T) (=KCTC 23156(T) =CECT 7710(T)).