Validation of pairs of antagonist teeth for the evaluation of shortened dental arch in epidemiological studies.

The aim of this study was to evaluate the accuracy of pairs of antagonist teeth (epidemiological criterion) for defining pairs of teeth in occlusal contact (clinical criterion) and to estimate the agreement between the prevalence of "shortened dental arch" (SDA) and "functional dentition" (FD) when occlusal units (OUs) or posterior occluding pairs (POPs) are defined by the epidemiological or clinical criterion. Data were collected in an epidemiological oral health survey conducted in a municipality in Minas Gerais, Brazil. OUs and POPs were defined by the epidemiological criterion (dental crown status) or clinical criterion "gold standard" (carbon paper record of occlusal contacts during habitual maximum intercuspation). SDA corresponded to the presence of an intact anterior region and three to five OUs. FD was based on the concomitant presence of ≥ 1 tooth in each arch, 10 teeth in each arch, 12 anterior teeth, ≥ 3 premolar POPs, and ≥ 1 molar POP bilaterally. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the epidemiological criterion were calculated. The study included 197 adults. Sensitivity, specificity, PPV, and NPV were 88.5, 87.9, 92.5, and 81.9%, respectively, and accuracy was 88.3%. The epidemiological criterion proved to be valid and could be used in epidemiological studies to calculate the prevalence of reduced dental configurations that consider POPs. The assessment of oral functionality is an aspect that should be included in the diagnosis of the clinical condition of patients, contributing to a more effective individual and collective oral health care plan.

Spontaneous changes in mandibular incisor crowding from mixed to permanent dentition: a systematic review.

INTRODUCTION: Dental crowding is the most prevalent malocclusion in the mixed and permanent detitions and can have a major impact on dentofacial esthetics. However, adjustments to the development and growth of the dentition can potentiate self-correction of dental crowding during childhood. OBJECTIVE: To evaluate the physiological behavior of mandibular incisor crowding in the transition from mixed to permanent dentition. METHODOLOGY: Five electronic databases (PubMed, Scopus, Web of Science, LILACS and LIVIVO) and part of the gray literature (Proquest and Google Scholar) were investigated, based on the eligibility criteria associated with the acronym PECO, until June 2022. The risk of bias was assessed using the ROBINS-E tool and the certainty of evidence, the GRADE tool. RESULTS: Among the 2.663 studies identified, five were selected for qualitative analysis, of which one have a low risk of bias, and four, a moderate risk. A total of 243 patients were evaluated. Evidence with a high level of certainty was generated indicating a tendency for improvement in mandibular incisor crowding from mixed to permanent dentition, with mandibular incisor crowding decreasing from 0.17 to 4.62 mm on average. The mandibular incisor crowding reduction seems to be associated with the amount of initial crowding and spontaneous dental arch dimensional changes that occur in the mixed dentition and culminate in the increase in arch perimeter, leeway space, incisor protrusion and transverse growth of the maxillary and mandibular arch. CONCLUSION: Based on moderate scientific evidence, spontaneous longitudinal changes in dental arch in the transition from the mixed to the permanent dentition demonstrate a spontaneous improvement in mandibular incisor crowding by up to 4.62 mm. These evidence provide a scientific basis for planning only longitudinal follow-up in patients with mild to borderline moderate mandibular incisor crowding in the mixed dentition avoiding overtreatment.

The impact of software updates on accuracy of intraoral scanners.

BACKGROUND: Digital workflow is showing an increasing tendency in everyday dentistry. Accuracy is essential during digital dental workflows for all indication areas. The present study aimed to evaluate the effect of software updates on the accuracy of intraoral scanner (IOS) devices. METHODS: 3Shape Trios 3 Pod with software versions 18.1.2. (TRI3_1) and 20.1.2. (TRI3_2); 3Shape Trios 4 Move, version 19.2.2. (TRI4_1); and 3Shape Trios 4 Pod, version 20.1.1. (TRI4_2) were used to take direct optical impressions from a polymethyl methacrylate (PMMA) full arch reference model with prepared teeth (FDI 11,14,17 for crowns and FDI 26 for onlay) and an edentulous region (between FDI 14 and 17). The scanners were used eight times; STL files were imported into Geomagic Control X for accuracy assessment by comparing them to a reference data set created by an industrial high-precision scanner (AICON SmartScan-3D C5). The average deviation of the surface points was calculated in three locations: across a full arch (Parameter 1), the region of a four-unit bridge (Parameter 2), and a single prepared abutment (Parameter 3). RESULTS: In parameter 1 and 2, the newest model with the latest software (TRI4_2) reached the highest accuracy (31.06 ± 5.24 µm and 21.69 ± 7.50 µm). In parameter 3, an older generation scanner running legacy software produced the highest accuracy: TRI4_1, 11.75 ± 0.35 µm. CONCLUSION: Appropriate software updates can significantly increase the trueness and precision of intraoral scanner devices. With updated software, the older generation can match the accuracy level of latest equipment.

Correlation between cleft width and dental arch symmetry in cleft lip and palate: a longitudinal study.

This study aimed to evaluate the influence of cleft width on dental arch symmetry of children with unilateral cleft lip and palate. Forty-one children were subjected to impression preoperatively (T1; mean age = 0.31 ± 0.07 years) and postoperatively (T2; mean age = 6 .73 ± 1.02 years). Eighty-two digitized dental casts were analyzed by stereophotogrammetry software. The cleft palate width was measured in the anterior (P-P'), middle (M-M'), and posterior (U-U') regions. Also, the following measurements were obtained: anterior intersegment (I-C') and intrasegment (I-C); total intersegment (I-T') and intrasegment (I-T); cleft-side (C'-T') and non-cleft-side (C-T) canine tuberosity. Paired t test and Pearson correlation coefficient were applied (α = 5%). Cleft width had the following means: 10.16 (± 3.46) mm for P-P', 12.45 (± 3.00) mm for M-M', and 12.57 (± 2.71) mm for U-U'. In the longitudinal analysis, I-C' had a significant reduction, while the other measurements significantly increased (p < 0.001). Asymmetry was verified in the following analyses at T1: I-C' vs. I-C and I-T' vs. I-T (p < 0.001); at T2, only in I-C' vs. I-C (p < 0.001). At T1, P-P' vs. I-C' (r = 0.722 and p < 0.001), P-P' vs. I-T' (r = 0.593 and p < 0.001), M-M' vs. I-C' (r = 0.620 and p < 0.001), and M-M' vs. I-T' (r = 0.327 and p < 0.05) showed a positive and significant correlation. At T2, there was a correlation between M-M' and I-C' (r = 0.377 and p < 0.05). In conclusion, the anterior and middle cleft widths influenced palatal asymmetry in the first months of life, while middle width influenced residual asymmetry.

Intraoral Scans of Full Dental Arches: An In Vitro Measurement Study of the Accuracy of Different Intraoral Scanners.

The aim of this in vitro study was to evaluate the accuracy of different intraoral scanners (IOS), according to different scanning strategies and to the experience of the operator. Six IOS setups were used in this study. Ten scans of a complete epoxy-resin-made maxillary dental arch were performed with each IOS, using four different scanning techniques (manufacturer-suggested scanning strategy, cut-out rescan technique, simplified scanning technique, novel scanning technique). Scans were also performed by an expert operator in the field of digital dentistry. An operator with no experience in the field of intraoral scans performed 10 scans following each of the scanning strategy suggested by the manufacturer. The master model was scanned with an industrial high-resolution reference scanner to obtain a highly accurate digitized reference model. All the digital models were aligned with the reference model using a software aimed at comparing the STL files. A total of n = 300 scans were performed. Once the data were pooled, Medit i700 and Primescan obtained the best results in terms of both trueness and precision, showing no statistically significative differences (p > 0.05) to the first and the second scanning technique, Medit i700 scanner allowed to obtain the best values both in terms of trueness (24.4 ± 2.1 µm and 21.4 ± 12.9 µm, respectively) and precision compared to other IOS (23.0 ± 1.6 µm and 30.0 ± 18.0 µm, respectively). When considering the third scanning technique, Medit i700 recorded the best values in terms of trueness while Primescan recorded the best values in terms of precision (24.0 ± 2.7 µm and 26.8 ± 13.7 µm, respectively). When considering the two operators, significant differences between the two were found only with Medit i700 (p < 0.001). The examined IOS showed statistically significant differences in terms of trueness and precision. The used scanning strategy is a factor influencing the accuracy of IOS. Considering the expertise of the operators, clinically scanning strategies are not operative sensitive in terms of accuracy.

Impact of shortened dental arch therapy on nutritional status and treatment costs in older adults: A systematic review.

OBJECTIVE: This review was undertaken to evaluate, whether a shortened dental arch (SDA) was a good alternative to a conventional prosthodontic rehabilitation (RPD) in older adults when nutritional and economic factors are compared. DATA: A total of 92 studies were included for the full-text analysis, and finally 4 reports from two RCTs qualified for data extraction and analysis. The final search update was performed on 06.11.2022 and no further searches and updates were performed after this date. SOURCES: Electronic databases [PubMed (MEDLINE), Embase, CENTRAL] were systematically searched to identify studies comparing nutritional and economic outcomes in partially edentate adults rehabilitated with conventional RPD and SDA therapy. STUDY SELECTION: Studies were excluded if there were less than 10 participants per group, and if the subjects were not clinically followed up in recall visits. Two investigators performed the data extraction and were reciprocally blinded. Inter-investigator reliability was assessed using Cohen's unweighted kappa (κ). A meta-analysis could not be performed and the results were reported qualitatively. RESULTS: The calculated κ ranged between 0.80 and 1.00. Three reports from two studies reported on nutritional outcomes and one report provided information on economic benefits, when comparing between the SDA therapy and conventional prosthodontic rehabilitation. No significant difference was recorded in the nutritional status of patients rehabilitated using the SDA concept compared with RPDs. Higher costs for treatment provision and maintenance for patients in the RPD group was found when compared to SDA treatment. CONCLUSIONS: This systematic review identified the shortened dental arch concept as a reasonable alternative to the conventional prosthodontic rehabilitation where cost-effectiveness and nutrition are concerned based on the limited evidence obtained from current literature. CLINICAL SIGNIFICANCE: SDA therapy may be considered as a feasible treatment concept in older adults especially in those with complex medical statuses and limited finances.

Does partial adhesive preparation design and finish line depth influence trueness and precision of intraoral scanners?

STATEMENT OF PROBLEM: Intraoral scanners (IOSs) are widely used for partial-coverage adhesive restorations, but data on their performance in such preparations with complex geometries are sparse. PURPOSE: The purpose of this in vitro study was to investigate whether the partial-coverage adhesive preparation design and finish line depth affect the trueness and precision of different IOSs. MATERIAL AND METHODS: Seven partial-coverage adhesive preparation designs (4 different onlays, 2 endocrowns, and 1 occlusal veneer) were tested on copies of the same tooth placed in a typodont mounted on a mannequin. Each preparation was scanned 10 times with 6 different IOSs (total 420 scans) under the same light conditions. Trueness and precision, defined according to the International Organization for Standardization (ISO) 5725-1 standard, were analyzed with a best-fit algorithm by superimposition. The obtained data were analyzed by a 2-way analysis of variance to examine the effects of partial-coverage adhesive preparation design, IOS, and their interactions (α=.05). RESULTS: Significant differences were found among different preparation designs and IOSs (P<.05) in terms of both trueness and precision. Significant differences were also found among mean positive and negative values (P<.05). Moreover, crosslinks observed between the preparation area and the adjacent teeth correlated with the finish line depth. CONCLUSIONS: Complex partial adhesive preparation designs affect the trueness and precision of IOSs, resulting in significant differences among them. Interproximal preparations should take into account the IOS's resolution and placing the finish line close to adjacent structures should be avoided.

Management of mandibular incisors crowding by using passive lower lingual holding arch: a case series and literature review.

Mandibular incisor crowding is a frequently encountered problem in daily orthodontic treatment. Success of the treatment greatly depends on the orthodontist's ability to manage the factors contributing to the existing crowding and implementing the proper interceptive means. The passive lower lingual holding arch (LLHA) helps maintain the position of the permanent first molars after the exfoliation of primary molars and canines. Thus, relieving the mandibular incisor crowding during transitional dentition. Four case reports age ranged from 11-13.5 years old were used to report the effect of using LLHA on mandibular incisor crowding. Little's Irregularity Index (LII) was used to assess the severity of mandibular incisors crowding as well as to compare the severity of the crowding before and after the use of LLHA. Passive LLHA could be considered the appliance of choice for space maintenance during the mixed dentition. Mandibular incisor crowding was reduced as measured by LII after the use of the passive LLHA over a duration of twenty months.

Incisor irregularity and dental arch dimensions changes in subjects with different severity of anterior crowding: a 37-year follow-up.

BACKGROUND: Occlusal stability is one of the goals of orthodontic treatment, and keeping teeth aligned in the long term is a challenge for the orthodontist. This study aimed to compare the long-term incisors irregularity and dental arches dimensions changes in subjects treated with 4 premolar extractions with different pretreatment Little's irregularity index (LII). The knowledge of long-term outcomes is evidence-based information for the prognosis of future treatments. METHODS: In total, 41 treated subjects were divided into two groups according to mandibular Little irregularity value at pretreatment (mild or severe). The maxillary and mandibular LII, transversal, and longitudinal widths were assessed at pretreatment, posttreatment, and 37-year posttreatment. Chi-square and independent t tests were used for intergroup comparison. RESULTS: The groups presented similar behavior for all stages of maxillary and mandibular arch dimensions changes. Maxillary irregularity was corrected in both groups after treatment, and the alignment was acceptable in the long term. In the mild group, the mandibular incisor irregularity returned to pretreatment values in the long term. The mandibular LII increased in the severe group but did not return to pretreatment values in the long term. CONCLUSIONS: The mild crowding group presented proportionally more relapse of mandibular incisor irregularity than the severe crowding group in the long term. Even so, the correction of mild and severe crowding with the extraction of 4 premolars showed satisfactory results in the long term, even with the presence of maturational changes and relapse.

Longitudinal behavior of orthodontic extraction spaces: A retrospective dental cast analysis.

INTRODUCTION: This retrospective study aimed to qualitatively and quantitatively evaluate orthodontic extraction space behavior and size at the end of treatment and the short- and long-term stages in Class I, II, and III malocclusions. METHODS: The sample comprised records of 1283 orthodontic patients treated with extractions (cross-sectional group). From these patients, 1- and 5-year posttreatment records of 214 patients were additionally evaluated (longitudinal group). Orthodontic extraction sites of immediate (end of treatment), short-term (1-year posttreatment), and long-term (5-year posttreatment) stage dental casts were measured with a digital caliper. Extraction spaces were classified according to their qualitative behavior in the open, closed, reopened, and recently closed spaces. Space qualitative longitudinal behavior was compared among the malocclusion types with chi-square tests. Kolmogorov-Smirnov normality tests were performed to check the variable's distribution. All variables showed normal distribution, except the malocclusion group ages. Therefore, parametric tests were used for all comparisons between the malocclusion groups, except for age comparisons in each stage, which were compared with the Kruskal-Wallis tests. Thus, space size and its reduction were compared among the 3 stages, in general, and between the maxillary and mandibular arches, with analysis of variance followed by Tukey tests and t tests, respectively. RESULTS: Classes I, II, and III malocclusion patients presented similar ages at each stage. At the end of treatment, 71.4% and 65.1% of the quadrants were closed in the cross-sectional and longitudinal groups, respectively, and 43.6% and 38.2% of patients presented all quadrants closed at this same stage in both groups. The reopening and late closure tendencies were 2.9 and 2.3 times greater in the short term than in the long term. Reopening tendency in the short-term was greater in Class II than in Class I malocclusion. Of the quadrants closed at the end of treatment, 87% were stable in the long term. From the quadrants with residual spaces at the end of treatment, 28.4% persisted openly in the long term. Residual space size reduced significantly in the short and long term, primarily in the mandibular arch. CONCLUSIONS: The percentage of patients with residual spaces at the end of treatment was 56.4%. Space reopening and late closure occur mainly in the first year after treatment. There was long-term stability in 87% of the quadrants closed at the end of treatment. There was a significant reduction in orthodontic extraction space size in the short and long term, especially in the mandibular arch.

A guide for maximizing the accuracy of intraoral digital scans: Part 2-Patient factors.

OBJECTIVES: To describe the factors related to patient intraoral conditions that impact the scanning accuracy of intraoral scanners (IOSs). A new classification for these influencing factors is proposed to facilitate dental professionals' decision-making and maximize the accuracy and reliability of intraoral digital scans. OVERVIEW: Variables related to intraoral conditions of the patient that can influence the scanning accuracy of IOSs include tooth type, presence of interdental spaces, arch width variations, palate characteristics, wetness, existing restorations, characteristics of the surface being digitized, edentulous areas, interimplant distance, position, angulation, and depth of existing implants, and implant scan body selection. CONCLUSIONS: The knowledge and understanding of the patient's intraoral conditions that can impact the scanning accuracy of IOSs is a fundamental element for maximizing the accuracy of IOSs. CLINICAL SIGNIFICANCE: The patient's intraoral conditions, or patient factors, can significantly impact intraoral scanning accuracy. Dental professionals must know and understand these influencing patient factors to maximize the accuracy of IOSs.

HOW TO IDENTIFY SUBGROUPS IN LONGITUDINAL CLINICAL DATA: TREATMENT RESPONSE PATTERNS IN PATIENTS WITH A SHORTENED DENTAL ARCH.

BACKGROUND: When dental patients seek care, treatments are not always successful,that is patients' oral health problems are not always eliminated or substantially reduced. Identifying these patients (treatment non-responders) is essential for clinical decision-making. Group-based trajectory modeling (GBTM) is rarely used in dentistry, but a promising statistical technique to identify non-responders in particular and clinical distinct patient groups in general in longitudinal data sets. AIM: Using group-based trajectory modeling, this study aimed to demonstrate how to identify oral health-related quality of life (OHRQoL) treatment response patterns by the example of patients with a shortened dental arch (SDA). METHODS: This paper is a secondary data analysis of a randomized controlled clinical trial. In this trial SDA patients received partial removable dental prostheses replacing missing teeth up to the first molars (N = 79) either or the dental arch ended with the second premolar that was present or replaced by a cantilever fixed dental prosthesis (N = 71). Up to ten follow-up examinations (1-2, 6, 12, 24, 36, 48, 60, 96, 120, and 180 months post-treatment) continued for 15 years. The outcome OHRQoL was assessed with the 49-item Oral Health Impact Profile (OHIP). Exploratory GBTM was performed to identify treatment response patterns. RESULTS: Two response patterns could be identified - "responders" and "non-responders." Responders' OHRQoL improved substantially and stayed primarily stable over the 15 years. Non-responders' OHRQoL did not improve considerably over time or worsened. While the SDA treatments were not related to the 2 response patterns, higher levels of functional, pain-related, psychological impairment in particular, and severely impaired OHRQoL in general predicted a non-responding OHRQoL pattern after treatment. Supplementary, a 3 pattern approach has been evaluated. CONCLUSIONS: Clustering patients according to certain longitudinal characteristics after treatment is generally important, but specifically identifying treatment in non-responders is central. With the increasing availability of OHRQoL data in clinical research and regular patient care, GBTM has become a powerful tool to investigate which dental treatment works for which patients.

Accuracy of four recent intraoral scanners with respect to two different ceramic surfaces.

OBJECTIVES: To investigate the complete arch accuracy of intraoral scanners (IOS) on two different ceramic surfaces. METHODS: Two maxillary master cast samples were prepared. The bases of both the master casts were made from zirconium oxide. The difference between the two casts was that the teeth of the [ZR] cast were produced from zirconium oxide and that of the [LD] cast were made of lithium disilicate glass-ceramic. Unlike the zirconia teeth of the [ZR] cast, the lithium disilicate teeth of the [LD] cast were glazed. The two master casts were digitized using a high-resolution scanner (Atos Compact Scan 5 M, GOM GmbH, Braunschweig, Germany) to obtain digital reference casts. Subsequently, each master cast was scanned 15 times using four IOSs. The IOSs were the Cerec Omnicam [OM], Primescan [PR], Trios 4 [TR4], and VivaScan [VS]. On surface comparison, the absolute mean deviation values were obtained for trueness and precision. For multiple comparisons, statistically significant differences were analyzed using one-way ANOVA and the Kruskal-Wallis H test. The p-value was adjusted to control for the increased risk of type I error (p < 0.0083). To compare the two means, the t-test and Mann-Whitney U test were used (p < 0.05). RESULTS: Trueness values for [ZR] ranged from 24.6 (±6.3) µm for [PR] and 77.1 (±8.3) µm for [OM]. Trueness values for [LD] were between 28.3 (±6.3) µm for [PR] and 72.8 (±15.6) µm for [OM]. Precision values for [ZR] ranged from 17.6 (±3.7) µm for [PR] to 37.3 (±9.9) µm for [OM]. Precision values for [LD] ranged from 17.5 (±3.6) µm for [PR] to 41.8 (±8.7) µm for [OM]. Statistically significant differences were found among all the IOSs (p < 0.0083). The trueness values of the four IOSs did not differ significantly (p < 0.05) with respect to either the [ZR] or [LD] cast. The precision values of [OM] and [VS] differed significantly with respect to the scanned surface. CONCLUSIONS: Complete arch scans achieved with the four IOSs showed significantly different trueness and precision results. [VS] and [OM] were more sensitive in terms of the scanned material. CLINICAL SIGNIFICANCE: The latest IOSs showed the required accuracy for complete arch digital impressions in-vitro investigations. These findings should be implemented under conditions relevant to complete arch deviations, such as the construction of occlusal splints, analysis of occlusal relationships, and long-span restorations. Clinicians should be aware that the clinically acceptable threshold varies depending on the purpose of the IOS.

In vitro comparison of five desktop scanners and an industrial scanner in the evaluation of an intraoral scanner accuracy.

OBJECTIVES: The study aimed to compare the precision of ATOS industrial, 3ShapeE4, MeditT710, CeramillMap400, CSNeo, PlanScanLab desktop, and Mediti700 intraoral scanners. The second aim was to compare the trueness of Mediti700 assessed by ATOS and desktop scanners. METHODS: Four plastic dentate models with 7-12 abutments prepared for complete arch fixed dentures were scanned by all scanners three times. Scans were segmented to retain only the abutments. The precision and trueness were calculated by superimposing scans with the best-fit algorithm. The mean absolute distance was calculated between the scan surfaces. The precision was calculated based on the 12 repeats. Trueness was evaluated by superimposing the desktop and IOS scans to the industrial scans. IOS was also aligned with the two most accurate desktop scanners. RESULTS: The precision of 3ShapeE4 and MeditT710 (3-4µm) was only slightly lower than that of ATOS (1.7µm, p<0.001) and significantly higher than CeramillMap400, CSNeo, and PlanScanLab (6-10 µm, p<0.001). The trueness was the highest for the 3Shape E4 (12-13 µm) and Medit T710 (13-16 µm) without significant difference. They were significantly better than CeramillMap400, CSNeo, and PlanScanLab (22-31µm, p<0.001). Accordingly, the Mediti700 trueness was evaluated by ATOS, 3ShapeE4, and MeditT710. The three trueness was not significantly different; ATOS (23-26 µm), 3Shape E4 (22-25 µm), and Medit T710 (20-23 µm). CONCLUSIONS: All desktop scanners had the acceptable accuracy required for a complete arch-fixed prosthesis. The 3Shape E4 and the Medit T710 might be used as reference scanners for studying IOS accuracy. CLINICAL SIGNIFICANCE: 3ShapeE4, MeditT710, CeramillMap400, CSNeo, PlanScanLab laboratory, and Mediti700 intraoral scanners can be used for the prosthetic workflow in a complete arch. 3ShapeE4 and the MeditT710 could be used to test the accuracy of various phases of a laboratory workflow, replacing the industrial scanners.

A guide for maximizing the accuracy of intraoral digital scans. Part 1: Operator factors.

OBJECTIVES: To describe the factors related to the operator skills and decisions that influence the scanning accuracy of intraoral scanners (IOSs). A new classification for these factors is proposed to facilitate dental professionals' decision making when using IOSs and maximize the accuracy and reliability of intraoral digital scans. OVERVIEW: Each IOS system is limited by the hardware and software characteristics of the selected device. The operator decisions that can influence the accuracy of IOSs include the scanning technology and system selection, scanning head size, calibration, scanning distance, exposure of the IOS to ambient temperature changes, ambient humidity, ambient lighting conditions, operator experience, scanning pattern, extension of the scan, cutting off, rescanning, and overlapping procedures. CONCLUSIONS: The knowledge and understanding of the operator factors that impact scanning accuracy of IOSs is a fundamental element for maximizing the accuracy of IOSs and for successfully integrating IOSs in daily practices. CLINICAL SIGNIFICANCE: Operator skills and clinical decisions significantly impact intraoral scanning accuracy. Dental professionals must know and understand these influencing operator factors for maximizing the accuracy of IOSs.

Maxillary arch dimensions, occlusion assessment and space conditions in patients with cleft palate in the period of deciduous dentition-A retrospective study.

PURPOSE: The aim of this study was to evaluate the maxillary arch dimensions, dentoalveolar relationships and spacing conditions in patients with cleft palate in comparison with the control group. METHODS: The subjects consisted of 31 children with cleft palate only (CP) aged 5.5 ± 0.51 (20 with a cleft of hard and soft palate (SHPC group) and 11 with a cleft of soft palate only (SPC group)). In the control group 30 subjects had a normal occlusion at age 5. Maxillary arch dimensions, dentoalveolar relationship according to the Huddard Bodenham index (HBI) and space conditions were compared with the control group. RESULTS: In all variables of maxillary arch dimensions except for total arch height the control group exhibited greater values. Most of the significant differences were on account of differences between the control and the SHPC group, with only three comparisons yielding significant results when comparing the two groups of children with clefts (SHPC vs SPC, IV-IV central: pDunnett T3= 0.0002, 95%CIDifference=-9.9-(-3.18); V-V distopalatal cusps: pDunnett T3= 0.0002, 95%CIDifference=-9.97-(-3.17); Total arch length: pDunnett T3= 0.0014, 95%CIDifference=1.74-7.85). The three groups differed significantly in anterior HBI only (HKruskal-Wallis=15.56, p = 0.0067). The spacing conditions in both jaws were also shown to be significantly dependent on the group of subjects studied (Upper jaw: χ2omnibus= 16.79, p = 0.0018; lower jaw: χ2omnibus= 13.75, p = 0.0102). CONCLUSIONS: The growth of the upper dental arch at the age of five is impeded in participants with CP in comparison to a control group. It is important to assess the effect of cleft subtypes on growth and development to get a better understanding.

Surgical effects of rehabilitation protocols on dental arch occlusion of children with cleft lip and palate

Aim: to evaluate the surgical effects of two rehabilitation protocols on dental arch occlusion of 5-year-old children with or without cleft lip and palate. Methods: this is a retrospective longitudinal study the sample comprised 45 digitized dental casts divided into followed groups: Group 1 (G1) ­ children who underwent to cheiloplasty (Millard technique) at 3 months and to one-stage palatoplasty (von Langenbeck technique) at 12 months; Group 2 (G2) ­ children who underwent to cheiloplasty (Millard technique) and two-stage palatoplasty (Hans Pichler technique for hard palate closure) at 3 months and at 12 months to soft palate closure (Sommerlad technique); and Group 3 (G3) ­ children without craniofacial anomalies. Linear measurements, area, and occlusion were evaluated by stereophotogrammetry software. Shapiro-Wilk test was used to verify normality. ANOVA followed by posthoc Tukey test and Kruskal-Wallis followed by posthoc Dunn tests were used to compared groups. Results: For the measures intercanine distance (C-C'), anterior length of dental arch (I-CC'), and total length of the dental arch (I­MM'), there were statistical differences between G1x G3 and G2xG3, the mean was smaller for G1 and G2. No statistically significant differences occurred in the intermolar distance and in the dental arch area among groups. The occlusion analysis revealed significant difference in the comparison of the three groups (p=0.0004). Conclusion: The surgical effects of two rehabilitation protocols affected the occlusion and the development of the anterior region of the maxilla of children with oral clefts when compared to children without oral clefts.

Dental arch characteristics among South Indian twins - A morphometric study

Genetic and environmental factors are essential in occlusal variations and malocclusion and have been of considerable interest to orthodontists. Studies on twin pairs are one of the most effective methods for investigating genetically determined occlusal variables. Many studies have focused on distances between first molars or between canines but malocclusions can also occur in other regions of the dental arch. Aim: To evaluate the characteristics of the dental arch between pairs of Monozygotic (MZ) and Dizygotic (DZ) twins from Southern India. Methods: A random sample of 51 twin pairs (12­18years old) participated in this study. The zygosity of twin pairs was recorded by facial appearance. The occlusion of the first permanent molars was recorded according to Angle's classification. Study models were prepared to assess dental arch characteristics (i.e., arch form, arch perimeter, arch length; intercanine, intermolar width, and teeth size discrepancy). The obtained data was statistically analyzed using SPSS software 19.0. The student's t-test (two-tailed, independent) and Chi-square test was used to determine the significance of studied parameters. Results: Angle's Class I molar relation was more commonly observed followed by the Class II molar relationship among twins. The measured dental arch dimensions did not show a statistically significant difference among twin pairs. The ovoid arch form was commonly observed among Monozygotic and Dizygotic Twins. There was a similarity among MZ and DZ twins in the anterior and overall Bolton's ratio. Conclusion: There were similar occurrences of measured parameters among twins, which showed genetic predominance in the expression of measured dental arch traits

Effect of preparation type on the accuracy of different intraoral scanners: An in vitro study at different levels of accuracy evaluation.

OBJECTIVE: Evaluation of the effect of preparation type (inlay, onlay, and crown) on the accuracy of different intraoral scanning (IOS) systems at the preparation and arch segment levels. MATERIALS AND METHODS: Three molars were prepared for inlay, onlay, and crown. Each preparation was scanned 10 times by CEREC Omnicam, Trios 3 (TS), and Medit i500 scanners. Each image was trimmed twice. The first trimming produced a preparation image (PI), and the second trimming extracted a segment image (SI) that involved the preparation with the adjacent teeth. Trueness and precision were calculated at the PI and SI levels. RESULTS: At the PI level, all IOS systems had similar trueness pattern for all preparations, where the inlay had the best trueness followed by the crown and onlay. At the SI level, the different preparations showed similar trueness. The precision did not show a clear pattern of superiority for any preparation. The TS was significantly more precise than other IOS systems at the PI and SI levels, for every preparation. The proximal areas suffered from the greatest errors, regardless of preparation type. CONCLUSIONS: The preparation type influenced PI trueness, and the IOS system affected PI and SI precisions. CLINICAL SIGNIFICANCE: The smaller and less complex preparations have greater IOS accuracy than larger and more complex preparations. As the proximal areas are more affected regardless of the preparation, a more accessible proximal area for scanning is desirable.