Esthetic outcomes in orthodontics through digital customization with a lingual appliance system.

BACKGROUND: Contemporary fixed orthodontic appliances are shifting from non-customized pre-adjusted appliances to custom-designed and printed appliances with novel digital setup systems. We are one step closer to precision dentistry and orthodontics using personalized mechanics and custom appliances. However, despite the evidential enhancement and other improvements to fixed appliances, tooth movement is still limited to five degrees of freedom. Opening or closing spaces still requires manually placing elastomeric chains or coil springs. AIM: In this article, we aimed to demonstrate how advancements in CAD/CAM technology, reverse engineering, and digital customization are helping orthodontics constantly evolve, enabling treatment with enhanced esthetics and minimal compliance. The clinical system (InBrace®, Irvine, CA) described in this article uses a patient-specific, digitally designed multiloop NITI wire that delivers friction-free, light, and continuous forces and activates automatically whenever the malocclusion deviates from the digital setup. CONCLUSION: Through digital customization, InBrace allows for automated tooth movement in all six degrees of freedom, including space opening or closure, via programmed non-sliding mechanics. CLINICAL SIGNIFICANCE: Precision orthodontics and personalized treatment have been significant developments in orthodontics recently. This article focuses on how a technologically advanced lingual appliance system could achieve targeted cosmetic results methodically via automation and personalization.

Nonextraction anterior open bite treatment with distalization and intrusion.

This case report describes successful orthodontic retreatment for vertical control with nonextraction orthodontic therapy. A 31-year-old woman complained of anterior open bite and crowding. She had slightly protrusive lips but wanted to correct her malocclusion without extraction. Two palatal temporary skeletal anchorage devices were used for the distalization of the maxillary arch along with posterior intrusion. Mandibular distalization was performed with Class III elastics. The duration of active treatment was 22 months. The plain and efficient mechanics used contributed to the effective distalization of both arches, the intrusion of the maxillary posterior teeth, and favorable profile changes. The results were still stable at the five-year follow-up period.

Connecting the dots towards precision orthodontics.

Precision orthodontics entails the use of personalized clinical, biological, social and environmental knowledge of each patient for deep individualized clinical phenotyping and diagnosis combined with the delivery of care using advanced customized devices, technologies and biologics. From its historical origins as a mechanotherapy and materials driven profession, the most recent advances in orthodontics in the past three decades have been propelled by technological innovations including volumetric and surface 3D imaging and printing, advances in software that facilitate the derivation of diagnostic details, enhanced personalization of treatment plans and fabrication of custom appliances. Still, the use of these diagnostic and therapeutic technologies is largely phenotype driven, focusing mainly on facial/skeletal morphology and tooth positions. Future advances in orthodontics will involve comprehensive understanding of an individual's biology through omics, a field of biology that involves large-scale rapid analyses of DNA, mRNA, proteins and other biological regulators from a cell, tissue or organism. Such understanding will define individual biological attributes that will impact diagnosis, treatment decisions, risk assessment and prognostics of therapy. Equally important are the advances in artificial intelligence (AI) and machine learning, and its applications in orthodontics. AI is already being used to perform validation of approaches for diagnostic purposes such as landmark identification, cephalometric tracings, diagnosis of pathologies and facial phenotyping from radiographs and/or photographs. Other areas for future discoveries and utilization of AI will include clinical decision support, precision orthodontics, payer decisions and risk prediction. The synergies between deep 3D phenotyping and advances in materials, omics and AI will propel the technological and omics era towards achieving the goal of delivering optimized and predictable precision orthodontics.

Evaluation of Dental Root Development Regarding Maxillary Canine Eruption Status after Secondary Alveolar Bone Grafting in Patients with Cleft Lip and Palate.

In children born with cleft lip and palate, the timing of the secondary alveolar bone graft (SABG) is crucial to its success; this involves estimating the eruption of the permanent maxillary canine. Altered dental eruption in this patient group gives impetus to the identification of dental developmental factors concerning maxillary canine eruption, which may steer the clinical decision of SABG timing. Records of over nine hundred patients who received SABG with pre- and post-operative cone beam computed tomography (CBCT) scans were analyzed for inclusion and divided into two groups (erupting or non-erupting canine after SABG). Roots of the maxillary canines and premolars were segmented from the cementoenamel junction then linear and volumetric measurements were performed. The pre- and post-operative root length and volume differences were calculated and compared statistically using independent sample tests and paired t-tests. No statistically significant differences were found in the volume change (%), or reciprocal of mean root length in the erupted and unerupted groups in the canine, first premolar, or second premolar roots except for an association between the post-operative dental root length of the canine and the maxillary canine eruption status. Therefore, assessment of root development from pre-treatment CBCT scans was not deemed worthy from a diagnostic perspective.

Clinical advances in maxillary skeletal expansion and introduction of a new MARPE concept.

BACKGROUND: Transverse maxillary deficiency, typically characterized by the clinical manifestations of unilateral or bilateral crossbite, is a common orthodontic discrepancy. The primary goal of maxillary expansion should be to obtain a nearly maximum width increase in the basal bone of the constricted maxilla and to avoid the dental expansion of the anchor teeth. The introduction of miniscrew anchorage-supported rapid maxillary expansion (MARPE) devices has helped increase the feasibility of obtaining nonsurgical transverse correction in late adolescents and young adults with optimum orthopedic effects. However, the success rate of MARPE shows a negative correlation with age. Although MARPE offers an effective method for correcting a transverse skeletal deficiency, given the appliance cost and increased risk for complications, it could present challenges for adult patients and practitioners in daily practice. AIMS: In this article, current advances in maxillary skeletal expansion are summarized, and a new MARPE concept is introduced. CONCLUSION: The new MARPE design offers several advantages to other existing methods: (1) it can be installed directly to the patient in the clinical setting with no additional laboratory waiting times. (2) It is purely a bone-borne appliance. (3) The appliance is designed to be placed in the thickest part of the anterior palate to maximize the cortical and trabecular bone support. (4) Allows for bicortical placement of the miniscrews with no perforations in the nasal floor. Finally, (5) offers an esthetic and minimalistic approach to maxillary skeletal expansion in late adolescent and adult patients.

Evaluation of current additive manufacturing systems for orthodontic 3-dimensional printing.

INTRODUCTION: The objective of this research was to evaluate and compare linear and surface accuracy of dental models fabricated using 3 different vat photopolymerization printing units: digital light synthesis (M2 Printer; Carbon, Redwood City, Calif), digital light processing (Juell 3D Flash OC; Park Dental Research, New York, NY), and stereolithography apparatus (Form 2; Formlabs Inc, Somerville, Mass), and a material jetting printing unit: PolyJet (Objet Eden 260VS; Stratasys, Eden Prairie, Minn). METHODS: Maxillary and mandibular dental arches of 20 patients with the American Board of Orthodontics Discrepancy Index scores ranging between 10 and 30 were scanned using an intraoral scanner. Stereolithographic files of each patient were printed via the 3-dimensional (3D) printers and were digitized again using a 3D desktop scanner to enable comparisons with the original scan data. One-sample t test and linear regression analyses were performed. To further graphically examine the accuracy between the different methods, Bland-Altman plots were computed. The level of significance was set at P <0.05. RESULTS: Bland-Altman analysis showed no fixed bias of one approach vs the other, and random errors were detected in all linear accuracy comparisons. When a 0.25 mm tolerance level was deemed acceptable for any positive or negative surface changes, only the models manufactured from digital light processing and PolyJet units showed more than 97% match with the original scans. CONCLUSION: The surface area of 3D printed models did not yield an utterly identical match to the original scan data and was affected by the type of printer. The clinical relevance of the differences observed on the 3D printed dental model surfaces requires application-specific judgments.

Functional characterization of ATF1, GREM2 AND WNT10B variants associated with tooth agenesis.

OBJECTIVE: To determine the functional effects of ATF1, WNT10B and GREM2 gene variants identified in individuals with tooth agenesis (TA). SETTINGS AND SAMPLE POPULATION: Stem cells from human exfoliated deciduous teeth (SHED) were used as an in vitro model system to test the effect of TA-associated variants. MATERIALS AND METHODS: Plasmid constructs containing reference and mutant alleles for ATF1 rs11169552, WNT10B rs833843 and GREM2 rs1414655 variants were transfected into SHED for functional characterization of variants. Allele-specific changes in gene transcription activity, protein expression, cell migration and proliferation, and expression of additional tooth development genes (MSX1, PAX9 and AXIN2) were evaluated. Data analyses were performed using Student's t-test. P-values ≤ .05 were considered statistically significant. RESULTS: Mutant variants resulted in significantly decreased transcriptional activity of respective genes (P < 0.05), although no changes in protein localization were noted. Expression of MSX1 was significantly decreased in ATF1- and GREM2-mutant cells, whereas PAX9 or AXIN2 mRNA expression was not significantly altered. Mutant WNT10B had no significant effect on the expression of additional TA genes. ATF1- and GREM2-mutant cells presented increased cell migration. Cell proliferation was also affected with all three mutant alleles. CONCLUSIONS: Our results demonstrate that ATF1, WNT10B and GREM2 mutant alleles have modulatory effects on gene/protein function that may contribute to TA.

Should dentistry be a specialty of medicine? Two viewpoints.

Dentistry and dental education are well-established domains with deep-rooted institutions, educational programs, organizational structures, and advanced specialty fields. Almost 100 years ago, Dr. William Gies, founder of the Columbia University College of Dental Medicine, stated that to best serve the oral health needs of the population, dentistry should be considered a specialty of medicine, and dental students should have the same solid foundation in the basic and clinical sciences as medical students. More recently, the report on "Advancing Dental Education in the 21st Century" recommends an increase in the integration of dental and medical education as a means to address 2 of its key challenges: "shrinking demand for dental services" and "shifting practice environment." However, it has also been argued that making dentistry and dental education a subspecialty of medicine and medical education will create logistical, structural, regulatory, and financial dilemmas. Instead of a drastic change to current dental educational, organizational, and institutional models, some argue a contemporary approach to dental education is required to ensure dentists are well prepared to address the healthcare needs of the population and future healthcare delivery systems and practice models. Recognizing the need for change in dental education to keep pace with changes in patient demographics and healthcare systems, the dental profession has the responsibility and opportunity to develop new models and paradigms that improve educational and clinical outcomes in our educational programs and future practice.

Referral patterns of pediatric dentists and general practitioners to orthodontists based on case complexity.

OBJECTIVE: The objectives of this research were to investigate and compare general and pediatric dentists' subjective judgments of orthodontic case complexity and to determine how their perceptions of case complexity influence their decisions to refer the patient to an orthodontist. METHODS: Twenty pediatric dentists and 21 general dentists participated in the study. Pretreatment orthodontic records of 20 patients with a variety of malocclusions and a range of American Board of Orthodontics Discrepancy Index (DI) scores were used. Respondents were asked about their background and training in orthodontics. They were also asked to identify the subjective complexity of each case with the use of a 100-point visual analog scale (VAS) and whether they would refer the patient to an orthodontic specialist. A mixed-model multivariate data analysis was used to evaluate the subjective case complexity with the use of fixed factors such as DI score, type of panel member, experience, annual continuing education rate, and gender. Generalized linear mixed models were used to investigate the referral patterns of the general dentists and pediatric dentists. Level of significance was set at P < 0.05 for all statistical analyses. RESULTS: General dentists appeared to provide more overall orthodontic treatment than pediatric dentists; many general dentists provide limited orthodontic treatment and clear aligner therapy (P < 0.05). The perceived complexity score for cases was not significantly different between the 2 groups (P = 0.82). The association between DI score and perceived complexity was similar in both groups (P = 0.183) and there was a high correlation between DI and VAS score in the sample (r = 0.71; 95% Cl 0.38-0.87). Pediatric dentists had higher referral rates for cases with DI scores both below and above 20. Significant differences were noted between the pediatric and general dentists in the individual case referral decision as evaluated by the DI (P < 0.037) and VAS (P < 0.042) scores. CONCLUSIONS: General dentists provided more orthodontic care than the pediatric dentists. Both groups identified case complexity similarly, with only minor differences, but pediatric dentists had higher referral rates to orthodontic specialists regardless of the initial case complexity.

Specialist training influences the ability to recognise orthodontic case complexity.

General dentists and other dental specialists may be treating orthodontic cases without a proper understanding of the key components of malocclusion. This mini-review aims to identify the discrepancies in recognition of orthodontic case complexity and to give an insight as to why advanced speciality training is a must for the provision of comprehensive orthodontic care.

Further evidence for the role of WNT10A, WNT10B and GREM2 as candidate genes for isolated tooth agenesis.

OBJECTIVE: To investigate the association of single nucleotide variants in the candidate genes WNT10A, WNT10B and GREM2 with isolated tooth agenesis. SETTING AND SAMPLE POPULATION: A total of 435 Caucasian individuals (88 cases with isolated tooth agenesis and 347 unrelated controls) were ascertained at the University of Texas Health Science Center at Houston School of Dentistry. Clinical and radiographic examination by orthodontists confirmed the diagnosis of tooth agenesis. Genetic evaluation excluded syndromic forms of tooth agenesis. MATERIALS AND METHODS: Saliva samples were collected as source of genomic DNA. Fourteen variants in/nearby WNT10A, WNT10B and GREM2 were genotyped to test for association with tooth agenesis. Genotyping was performed using TaqMan chemistry in a real-time polymerase chain reaction assay. Allelic and haplotype frequencies were compared among cases and controls using chi-square tests as implemented in PLINK v.1.06. Bonferroni correction was used and P ≤ 0.004 indicates statistical differences between groups. RESULTS: Significant associations were found between individual SNPs and SNP combinations in WNT10A, WNT10B and GREM2 SNPs with isolated tooth agenesis (P < 0.004). CONCLUSION: Our findings further support a role for variants in WNT10A, WNT10B and GREM2 genes in the aetiology of isolated tooth agenesis. Functional studies are necessary to investigate the biological effects of these gene variants in tooth agenesis phenotypes.

Evaluation of miniscrew-supported rapid maxillary expansion in adolescents: A prospective randomized clinical trial.

OBJECTIVES:: To evaluate and compare the dental and skeletal changes with conventional and miniscrew-supported maxillary expansion appliances in adolescents. MATERIALS AND METHODS:: Forty patients were divided into two groups, with one group receiving a tooth-borne expander and the other group receiving an expander supported by four miniscrews (bone-borne). Multiplanar coronal and axial slices obtained from cone-beam computed tomography images were used to measure the changes in transverse skeletal widths, buccal bone thickness, tooth inclination, and root length. Paired t-tests and independent-sample t-tests were used to compare the two expansion methods. RESULTS:: Bone-borne expansion increased the maxillary suture opening more than 2.5 times than tooth-borne expansion both anteriorly and posteriorly. Between the maxillary first premolars, sutural expansion accounted for 28% and 70% of the total transverse width increase in the tooth-borne and bone-borne expander groups, respectively. Similarly, 26% and 68% of the total expansion was of skeletal nature in the tooth-borne and bone-borne expander groups between the maxillary first molars. The pattern of expansion was variable, with most of the patients in both groups demonstrating a triangular-shaped sutural opening that was wider anteriorly. Subjects in the conventional group experienced significantly more buccal bone reduction and greater buccal inclination of the teeth. No significant differences were observed for root length measurements between the two groups. CONCLUSION:: Use of bone-borne expansion in the adolescent population increased the extent of skeletal changes in the range of 1.5 to 2.8 times that of tooth-borne expansion and did not result in any dental side effects.

Colorectal Cancer-Associated Genes Are Associated with Tooth Agenesis and May Have a Role in Tooth Development.

Previously reported co-occurrence of colorectal cancer (CRC) and tooth agenesis (TA) and the overlap in disease-associated gene variants suggest involvement of similar molecular pathways. Here, we took an unbiased approach and tested genome-wide significant CRC-associated variants for association with isolated TA. Thirty single nucleotide variants (SNVs) in CRC-predisposing genes/loci were genotyped in a discovery dataset composed of 440 individuals with and without isolated TA. Genome-wide significant associations were found between TA and ATF1 rs11169552 (P = 4.36 × 10-10) and DUSP10 rs6687758 (P = 1.25 × 10-9), and positive association found with CASC8 rs10505477 (P = 8.2 × 10-5). Additional CRC marker haplotypes were also significantly associated with TA. Genotyping an independent dataset consisting of 52 cases with TA and 427 controls confirmed the association with CASC8. Atf1 and Dusp10 expression was detected in the mouse developing teeth from early bud stages to the formation of the complete tooth, suggesting a potential role for these genes and their encoded proteins in tooth development. While their individual contributions in tooth development remain to be elucidated, these genes may be considered candidates to be tested in additional populations.

Accuracy of 3-dimensional curvilinear measurements on digital models with intraoral scanners.

INTRODUCTION: Our objectives were to evaluate and compare the digital dental models generated from 2 commercial intraoral scanners with manual measurements when performing 3-dimensional surface measurements along a curved line (curvilinear). METHODS: Dry mandibles (n = 61) with intact dentition were used. The mandibles were digitized using 2 chair-side intraoral scanners: Cadent iTero (Align Technology, San Jose, Calif) and Lythos Digital Impression system (Ormco, Orange, Calif). Digitized 3-dimensional models were converted to individual stereolithography files and used with commercial software to obtain the curvilinear measurements. Manual measurements were carried out directly on the mandibular teeth. Measurements were made on different locations on the dental arch in various directions. One-sample t tests and linear regression analyses were performed. To further graphically examine the accuracy between the different methods, Bland-Altman plots were computed. The level of significance was set at P <0.05. RESULTS: There were no significant differences between any of the paired methods; this indicated a certain level of agreement between the methods tested (P >0.05). Bland-Altman analysis showed no fixed bias of 1 approach vs the other, and random errors were detected in all comparisons. Although the mean biases of the digital models obtained by the iTero and Lythos scanners, when compared with direct caliper measurements, were low, the comparison of the 2 intraoral scanners yielded the lowest mean bias. No comparison displayed statistical significance for the t scores; this indicated the absence of proportional bias in these comparisons. CONCLUSIONS: The intraoral scanners tested in this study produced digital dental models that were comparatively accurate when performing direct surface measurements along a curved line in 3 dimensions.

Smile esthetics: Evaluation of long-term changes in the transverse dimension.

OBJECTIVE: To analyze the long-term changes in maxillary arch widths and buccal corridor ratios in orthodontic patients treated with and without premolar extractions. METHODS: The study included 53 patients who were divided into the extraction (n = 28) and nonextraction (n = 25) groups. These patients had complete orthodontic records from the pretreatment (T1), posttreatment (T2), and postretention (T3) periods. Their mean retention and postretention times were 4 years 2 months and 17 years 8 months, respectively. Dental models and smiling photographs from all three periods were digitized to compare the changes in three dental arch width measurements and three buccal corridor ratios over time between the extraction and nonextraction groups. Data were analyzed using analysis of variance tests. Post-hoc multiple comparisons were made using Bonferroni correction. RESULTS: Soft-tissue extension during smiling increased with age in both groups. The maximum dental width to smile width ratio (MDW/SW) also showed a favorable increase with treatment in both groups (p < 0.05), and remained virtually stable at T3 (p > 0.05). According to the MDW/SW ratio, the mean difference in the buccal corridor space of the two groups was 2.4 ± 0.2% at T3. Additionally, no significant group × time interaction was found for any of the buccal corridor ratios studied. CONCLUSIONS: Premolar extractions did not negatively affect transverse maxillary arch widths and buccal corridor ratios. The long-term outcome of orthodontic treatment was comparable between the study groups.

Perceptions of orthodontic case complexity among orthodontists, general practitioners, orthodontic residents, and dental students.

INTRODUCTION: Our aims were to assess the perceptions of orthodontic case complexity among orthodontists, general dentists, orthodontic residents, and dental students and to compare their perceptions with the American Board of Orthodontics Discrepancy Index (DI). METHODS: Orthodontists, general dentists, orthodontic residents, and dental students (n = 343) participated in a Web-based survey. Pretreatment orthodontic records of 29 cases with varying DI scores were obtained. Respondents were asked to evaluate case complexity on a 100-point visual analog scale. Additional information was collected on participants' orthodontic education and orthodontic treatment preferences. Pearson correlation coefficients were used to assess the relationship between the average complexity score and the DI score. Repeated measures analysis with linear mixed models was used to assess the association between the average complexity score and the DI score and whether the association between the 2 scores varied by level of difficulty or panel group. The level of significance for all analyses was set at P <0.05. RESULTS: The results showed that 71.6% of general dentists provided some orthodontic services, with 21.0% providing full fixed appliances and 38.3% providing clear aligners. DI score was significantly associated with complexity perceptions (P = 0.0168). Associations between average complexity and DI score varied significantly by provider group (P = 0.0033), with orthodontists and residents showing the strongest associations. When the DI score was greater than 15, orthodontists and residents perceived cases as more complex than did the other provider groups. CONCLUSIONS: Orthodontists and orthodontic residents had better judgments for evaluating orthodontic case complexity. The high correlation between orthodontic professionals' perceptions and DI scores suggested that additional orthodontic education and training have an influence on the ability to recognize case complexity.

Accuracy and mechanical properties of orthodontic models printed 3-dimensionally from calcium sulfate before and after various postprinting treatments.

INTRODUCTION: Dental models fabricated with 3-dimensional printing technologies are revolutionizing the practice of orthodontics, but they generally comprise polymeric materials that may not be suitable for certain applications, such as soldering appliances. The objective of this study was to investigate the dimensional accuracy and mechanical properties of 3-dimensional printed ceramic-based models before and after various treatments intended to improve their mechanical properties. METHODS: Thirty identical models were printed 3-dimensionally from a calcium sulfate-based substrate and divided into 3 groups for treatment: high heat (250°C for 30 minutes), low heat (150°C for 30 minutes), and Epsom salt treatment. Each model was scanned before and after treatment with a laser scanner, and dimensional stability was analyzed by digital superimpositions using a best-fit algorithm. The models were weighed before and after treatment to evaluate mass changes. Additionally, 3-dimensional printed cylinders treated as described above and an untreated control group were subjected to compressive mechanical testing (n = 11 per group). RESULTS: The Epsom salt treatment group had statistically significant increases in both peak compressive stress and modulus of elasticity when compared with the other treatment groups. All treatment groups had statistically significant changes in mass, with the Epsom salt group gaining mass and the 2 heat-treatment groups losing mass. The low-temperature treatment group had a statistically significantly lower mean average for dimensional deviations (0.026 ± 0.010 mm) than did the other treatment groups (0.069 ± 0.006 and 0.059 ± 0.010 mm for high temperature and Epsom salt, respectively). CONCLUSIONS: Dental models printed 3-dimensionally with calcium sulfate and treated with Epsom salt showed significant improvement in compressive mechanical properties and retained clinically acceptable dimensional stability.

Evaluation of staining and color changes of a resin infiltration system.

OBJECTIVE: To analyze the staining and color changes of a resin infiltrant system used for management of white spot lesions (WSLs). MATERIALS AND METHODS: WSLs were artificially created on left buccal halves of 48 extracted human teeth. These sites were then treated with resin infiltration (RI) while the right halves of the teeth remained as nonresin (NRI) areas. Six groups were formed (n = 8 teeth/group) and were exposed to the following: red wine, coffee, orange juice, combined staining agents, accelerated aging, and distilled water for 1 week. The teeth were then polished with a prophy cup and polishing paste. Color properties were assessed using a spectrophotometer at baseline (T0), after each exposure (T1), and after polishing (T2). Color difference (ΔE*) was calculated between each time point for both halves of the teeth (RI and NRI). Data were analyzed with a two-way analysis of variance with presence of resin infiltration and staining agents as the main effects for each time point pair. Multiple comparisons were made with a Bonferroni post hoc test. The level of significance was set at P < .05. RESULTS: The red wine and combined staining agent groups caused the greatest color change between all intervals (P < .05). Significant interactions were recorded between resin infiltration application and staining agents at all time periods (P < .05). The presence of resin infiltration as a main effect did not affect color change between T0 and T2 (P > .05). CONCLUSIONS: RI areas showed higher staining susceptibility than did NRI areas. However, prophylaxis had a strong effect on reversing the discoloration of both RI and NRI areas.

Color Properties of Demineralized Enamel Surfaces Treated with a Resin Infiltration System.

OBJECTIVE: To assess color properties of white spot lesions (WSLs) following resin infiltration treatment in vitro. MATERIALS AND METHOD: WSLs were artificially created on 30 extracted human teeth. Two groups were formed: (a) control, and (b) resin infiltrant group (n = 15, each). Instrumental color measurements were performed using a spectrophotometer and visual color evaluation was performed by three independent evaluators. Color assessment was determined at three time points: baseline (T0), after WSL formation (T1), and after resin infiltrant or control treatment (T2). CIELAB color coordinates were determined and the resultant color difference (ΔE*) was calculated between the time points. Two-way repeated measures analysis of variance (ANOVA) and One-way ANOVA analyses were used to evaluate the color changes. Pearson chi-square analysis was performed to evaluate the visual ratings between treatment and control groups. Level of significance was set p <0.05. RESULTS: After treatment of WSLs there was a significant color change (ΔE*) between treatment and control groups (p <0.05). Resin infiltration group showed a regression of all values toward the pretreatment levels. There was a significant difference in visual evaluation ratings between groups after treatment; treatment group had all surfaces receive a rating of being clinically acceptable, with 73% of these surfaces having no perceptible color difference to adjacent sound enamel. Meanwhile, control group received ratings of all surfaces having a visual color difference that was deemed as unacceptable (p < 0.05). CONCLUSION: In-vitro resin infiltration for the treatment of enamel WSLs produced a significant improvement in color, reverting L*, a*, and b* values back toward baseline values. CLINICAL SIGNIFICANCE: Resin infiltration of enamel white spot lesions on teeth is capable of managing the esthetic problem by reverting the L*, a*, and b* color coordinates back to their baseline values. (J Esthet Restor Dent 28:339-346, 2016).

Analysis of smile esthetics in American Board of Orthodontic patients.

OBJECTIVE: To investigate the common denominators of an esthetically pleasing smile in patients who were considered to be successfully treated upon the submission to American Board Orthodontics (ABO) clinical examination. MATERIAL AND METHODS: A total of 462 patients were examined. Ninety subjects that fulfilled the inclusion criteria were included. Standardized digital smile photographs of the subjects were rated by 30 panel members, including orthodontists, general dentists, and parents of orthodontic patients, using a numeric version of the visual analog scale. Three groups were formed using the mean esthetic score±standard deviation range: unattractive (n=21), average (n=47), and attractive (n=22) smiles. Eleven smile characteristics were digitally measured on the photographs and compared between the groups using one-way analysis of variance and χ2 tests. Additionally, regression analyses were used to investigate the association of the smile characteristics with the esthetic score. RESULTS: A significant difference was found between the three groups for the comparison of smile arc relationship (P<.001). When all the variables used in this study were entered in the regression analysis, a positive association was found (r=0.658; r2=0.434; P<.001). Additionally, two models were defined using stepwise regression. The first model included the smile arc (r=0.478; r2=0.228; P<.001), and the second model had both the smile arc and right gingival display/visible dentition display ratio (r =0.567; r2=0.321; P<.001). CONCLUSIONS: A harmonious smile arc relationship and less gingival display during a smile are significantly associated with smile attractiveness in patients considered successfully treated according to ABO standards.