Model-free digital workflow and immediate functional loading of implant-supported monolithic glass-ceramic crowns: A case series.

OBJECTIVES: The aim of this study was to evaluate surgical and prosthetic outcomes of immediate functional loading of implants with glass-ceramic screw-retained single crowns. METHODS: A total of 22 implants were placed. Within 24 h, functional full-contour glass ceramic crowns were delivered to patients. The amount of attached gingiva, Simplified Oral Hygiene Index Score, bleeding on probing, time after extraction, bone type, implant size, soft tissue thickness, primary stability, a general fit of the restoration, occlusal and proximal contacts were recorded. Restorations were followed-up at 1, 3, and 6 months tracking marginal bone loss (MBL), noting changes in occlusal and interproximal contacts, checking other possible complications. RESULTS: One implant failed and was removed after 4 weeks (95.5% survival rate). The rest of the implants and crowns functioned with no complications during the follow-up period of 6 months. Factors such as time after extraction, bone type, implant size, soft tissue thickness, and primary stability recorded in Ncm and implant stability quotient (ISQ) values, were not associated with MBL (p<0.05). Mean MBL was found to be 0.3 mm (standard deviation = 0.42) mesially and 0.4 mm (standard deviation = 0.66) distally. One distal and one mesial proximal contact were found to be missing at the 6-month check-up appointment. CONCLUSIONS: Within the limits of this study, fully digital workflow without a 3D printed model could be successfully employed for immediate functional loading with single-unit implant-supported crowns. Further studies are needed to obtain long-term results with a larger sample of patients. CLINICAL SIGNIFICANCE: Model-free digital workflow and immediate functional loading of implant-supported monolithic glass-ceramic crown might be viable option to restore a single tooth defect.

Microcomputed tomography evaluation of contamination with endodontic obturation material remnants in teeth with different root canal anatomy after post space preparation.

STATEMENT OF PROBLEM: Whether the amount of the endodontic obturation material remnants in a root canal prepared for a post is related to variations in the anatomic shape of the canal or whether it varies in different parts of the post space is unclear. PURPOSE: The purpose of this in vitro study was to estimate the extent of root canal contamination with remnants of the obturation material after post space preparation in relation to the anatomic shape of the root canals by means of microcomputed tomography. MATERIAL AND METHODS: Fifty freshly extracted teeth were divided into 5 test groups with respect to the root anatomy of different tooth types. The root canals were shaped and obturated with gutta percha. The space for the glass fiber post was prepared with standardized drills, and all specimens were scanned by microcomputed tomography. The areas of residual obturation material on the root canal walls in the coronal and apical parts of the prepared post space were estimated by using a 3D visualization software program. Parametric and nonparametric dispersive analysis (analysis of variance and Kruskal-Wallis) and Wilcoxon tests were used for statistical data evaluation (α=.05). RESULTS: The estimates of the root canal surface areas contaminated with residual obturation material after post space preparation were significantly larger in premolars (P≤.01), as compared with mandibular incisors and with the palatal roots of maxillary first molars. The contamination areas in different parts of the root canal (apical and coronal) reported significant differences within and between the test groups. CONCLUSIONS: The extent of root canal contamination with remnants of endodontic obturation material after post space preparation was related to the anatomic shape of the roots and varied in the coronal and apical parts of the prepared post space.

Oral bony outgrowths: prevalence and genetic factor influence. Study of twins.

OBJECTIVE: The aim of the study was to verify the influence of a genetic factor on the etiology of oral bony outgrowths and to determine the prevalence and type of oral bony outgrowths (tori and exostoses) among a group of Lithuanian twins. MATERIALS AND METHODS: In total, 162 twins (81 twin pairs) were analyzed for the presence or absence, type, and size of oral bony outgrowths. Statistical analysis was carried out to find the prevalence of bony protuberances and the relationship between zygosity and occurrence of oral bony enlargements. Zygosity of twins was confirmed by DNA analysis. RESULTS: 59.9% of the subjects had oral bony outgrowths. Mandibular tori were found in 56.8% and palatal tori in 1.8% of the sample. Palatal exostoses and mandibular exostoses were present in 1.8% and 3.1% of the sample, respectively, whereas maxillary exostoses were not found. A higher percentage of tori and exostoses were found in the group of older subjects (>18 years old, p=0.025). No significant difference was found between men and women in the prevalence of bony outgrowths. High κ and r values (0.91±0.062) showed very good concordance of oral bony outgrowths between monozygotic and moderate concordance (0.58±0.141) between dizygotic co-twins (p<0.001). The calculation of heritability estimate verifies dominant influence of genetic factor on the etiology of oral bony outgrowths (h(2)=0.658). CONCLUSION: The most common bony outgrowth was torus mandibularis. Our results show that the genetic factor is dominant in the etiology of oral bony outgrowths.

Multifactorial etiology of Torus mandibularis: study of twins.

OBJECTIVE: The aim of this study is to investigate the multifactorial etiology of mandibular tori analyzing the influence of genetics, occlusal overload, various clinical variables and their interactions. METHODS: Overall, plaster casts of 162 twins (81 twin pairs) were analyzed for the presence or absence of mandibular tori. Atypical wear facets on canine tips or incisors were recorded to diagnose bruxism. Angle Class, any kind of anterior open bite and positive, negative or flat curve of Wilson were recorded. Zygosity determination was carried out using a DNA test. RESULTS: Mandibular tori were found in 56.8% of the cases. In 93.6% of all monozygotic twin pairs both individuals had or did not have mandibular tori (κ=0.96±0.04; p<0.001), compared to 79.4% concordance of mandibular tori in dizygotic co-twins (κ=0.7±0.12; p<0.001). Prevalence of mandibular tori was significantly higher in the group of bruxers (67.5%) compared to non-bruxers (31.3%) (p<0.001). Significant association between mandibular tori and negative or flat curve of Wilson in the maxillary second premolars and first molars was found (OR=2.55, 95% CI (1.19-5.46), p=0.016). In all monozygotic bruxers, 97.1% showed concordance of mandibular tori presence in both co-twins compared to 78.9% dizygotic bruxers, and this difference is statistically significant (p=0.007). CONCLUSION: Our results suggest that the mandibular tori are of a multifactorial origin. Mandibular tori seem to have genetic predisposition, and may be associated with teeth grinding as well as with negative or flat CW in region of maxillary second premolar and first molar.

Symmetry of external auditive meatus. A pilot study on human skulls.

OBJECTIVES. To evaluate the perpendicularity of the line connecting external auditive meatus to the midsagital plane and the palatal suture as a midsagittal symmetry reference line. Setting and Sample Population - 62 randomly chosen human skulls from osteological collection (Vilnius University). MATERIAL AND METHODS. The skulls were photographed (Nikon 40 D, Nikkor lens 50 mm) from basal, frontobasal and frontal views. Photos were analysed with Adobe Photoshop CS5 (Adobe). The first line connected frontal points of external auditive meatus and the angle to the midsagittal plane was measured. The second line (the palatal suture) was compared to the median sagittal plane. Data was analysed with SPSS 17 (IBM). RESULTS. The mean value for the angles of the line between the external auditive meatus and the midsagittal plane in basal views was 90.12° (SD=1.48°) and in frontobasal 90.36° (SD=2.25°). No statistically significant differences were found between groups of age and sex. The inter-rater agreement for evaluation of the adequacy of palatal suture with the midsagital plane was high (Cohen's Kappa 0.702 (p<0.05)) as well as the coincidence of both lines in basal and frontobasal views (90.3% and 85.5% respectively). CONCLUSION. Considering the limits of this study the angle between external auditive meatus and midsagital skull plane has a characteristic fluctuating asymmetry. The congruence of palatal suture and midsagital plane is debatable.