Crown Dimensions Research Articles

Machine learning-based prediction of tree crown development in competitive urban environments

In urban forestry, managing trees is crucial for sustainable urban environments, especially in the context of climate change and the urban heat island effect. This research explores the complex dynamics of tree crown geometry development by asking the question: how do surrounding objects, such as nearby trees, buildings, and other urban structures, affect the shape of tree crowns? It aims to uncover how competition for light and space influences tree crown development in competitive urban environments. Our study employs machine learning models on six main species in Munich, using the measured data from the LiDAR scans, with the Hist Gradient Boosting Regressor (HGBR) emerging as the most promising performer across various metrics. Notably, the evaluation of 13 models reveals the HGBR’s consistent ranking as the best or second-best across all tree crown dimensions assessed, with R2 values reaching 0.83 for the tree height model and 0.7 on average for crown radiuses in eight directions. Employing SHapley Additive exPlanations (SHAP) values elucidate factors influencing model predictions, emphasising the significant impact of adjacent trees and buildings. After evaluating the models to include additional tree species in Munich, the models show strong predictive capabilities for some additional species. Despite the studies’ limitations - the models are only valid for selected species, and there are constraints in predicting tree crown start height - our findings contribute valuable insights for urban forestry management and planning.

Monitoring ink disease epidemics in chestnut and cork oak forests in central Italy with remote sensing

Forests provide multiple ecosystem services including water and soil protection, biodiversity conservation, carbon sequestration, and recreation, which are crucial in sustaining human health and wellbeing. Global changes represent a serious threat to Mediterranean forests, and among known impacts, there is the spread of invasive pests and pathogens, often boosted by climate change and human pressure. Remote sensing can provide support to forest health monitoring, which is crucial to contrast degradation and adopt mitigation strategies. Here, different multispectral and SAR data are used to detect the incidence of ink disease driven by Phytophthora cinnamomi in forest sites in central Italy, dominated by chestnut and cork oak respectively. Sentinel 1, Sentinel 2, and PlanetScope data, together with ground information, served as input in Random Forests to model healthy and disease classes in the two sites. The results indicate that healthy and symptomatic trees are clearly distinguished, whereas the discrimination among disease classes of different severity (moderate and severe damage) is less accurate. Crown dimension and sampled spectral regions are a critical factors in the selection of the sensor; better results are obtained for the larger chestnut crowns with Sentinel 2 data. In both sites, the red and near infra-red bands from multispectral data resulted well suited to monitor the spread of the ink disease.

The Relationship between the Length/Width of the Face and the Length/Width of the Crown of the Permanent Upper Central Incisors.

Background: The face, with its attractiveness, is positively connected with self-esteem and interpersonal relationships, and the maxillary central incisors are the most noticeable teeth and crucial for smile aesthetics. The aim of this study is to examine facial and permanent upper central incisors' clinical crown dimensions and their correlations to establish whether there is a relationship between the length/width of the face and the length/width of the clinical crown of the permanent upper central incisors. Methods: This study included 100 subjects (43 males and 57 females) with a mean age of 17.5 ± 3.4 years before orthodontic treatment. Facial length and width were measured using a cephalometer by the same orthodontist and the upper central incisors' clinical crown lengths and widths were measured using a sliding calliper by the same dental student. Data were analysed using SPSS version 29.0, presenting descriptive statistics for age, facial and upper central incisor crown dimensions, and indices. Pearson's correlation coefficient assessed the relationship between facial features and the upper central incisors' crown. The significance level was p ≤ 0.05. Results: Males exhibit a slightly higher mean value of the face length (11.6 ± 0.8 cm) compared to females' face length (11.2 ± 1.1 cm) and a statistically significant (p < 0.05) higher mean value of the face width (11.7 ± 0.8 cm) compared to females (11.1 ± 0.6 cm). The facial index shows no statistically significant gender difference (males: 99.1 ± 8.4; females: 101.2 ± 11.9, p > 0.05). The upper central incisor crown dimensions are without statistically significant differences between gender and tooth side: males have mean value clinical crown lengths of 10.2 ± 1.1 mm (left) and 10.1 mm ± 1.2 (right) while females have 9.9 ± 1.0 mm (left) and 9.8 ± 0.7 mm (right). Clinical crown widths are also comparable (males: left 9.0 ± 0.7, right 8.9 ± 0.6 and females: left 8.8 ± 0.7, right 8.8 ± 0.7), with no statistically significant differences observed. The tooth index shows no statistically significant difference but there is a statistically significant (p < 0.05) correlation between the facial index and tooth index. Conclusions: Knowledge of the presented data is important for diagnosis and treatment planning and may be useful for restorative dentists, orthodontists, prosthodontists, and maxillofacial surgeons to achieve an aesthetic result. Clinically, our study supports the development of more personalized treatment plans.

Comparative Study of Mesiodistal Crown Dimensions and Tooth Size Discrepancies of Thalassemia and Control Iraqi Patients

Aims: To find differences in mesiodistal tooth width in Iraqi B thalassemia compared with normal individuals. Setting and design: 44 subjects, 22 thalassemia (11 males, 11 females) (12.5–22) years, and 22 control (11 males, 11 females) 14–23 years. Methods and Material: Registrations of MD for maxillary and mandibular teeth from the first molar on one side to analogous tooth on the other side were done. Statistical analysis: Mean, standard deviation and 2-sampled t-test were used. Results: In both groups, males’ crown size was greater than females. In the study group largest gender variances appear in the maxillary molars, mandibular molar, maxillary central and maxillary canine respectively. In control, the greatest sexual difference is present in the maxillary first premolar followed by the mandibular second premolar. The means of mesiodistal in both sexes in thalassemia were smaller than in control except in male maxillary central and lateral and female maxillary lateral incisor. In the maxilla, a significant decrease in mesiodistal thalassemia is present in canine and second premolar in both sexes. In the mandible, a significant decrease in thalassemia was present in all comparisons in both genders in comparison with the control. The greatest mesiodistal difference in the mandibular male is present in the first molar, first premolar, second premolar, canine, lateral and central incisor respectively. In female mandibular teeth, the greatest difference is present in the first molar followed by the first premolar, second premolar, canine, lateral incisor and central incisor. Conclusions: Means mesiodistal dimensions in thalassemia show a significant reduction in mandibular teeth and maxillary canine and second premolar in both genders.

From hunter-gatherers to food producers: New dental insights into the Nile Valley population history (Late Paleolithic-Neolithic).

This study presents biological affinities between the last hunter-fisher-gatherers and first food-producing societies from the Nile Valley. We investigate odontometric and dental tissue proportion changes between these populations from the Middle Nile Valley and acknowledge the biological processes behind them. Dental remains of 329 individuals from Nubia and Central Sudan that date from the Late Pleistocene to the mid-Holocene are studied. Using 3D imaging techniques, we investigated outer and inner metric aspects of upper central incisors, and first and second upper molars. Late Paleolithic and Mesolithic foragers display homogeneous crown dimensions, dental tissue proportions, and enamel thickness distribution. This contrasts with Neolithic trends for significant differences from earlier samples on inner and outer aspects. Finally, within the Neolithic sample differences are found between Nubian and Central Sudanese sites. Substantial dental variation appears to have occurred around 6000 bce in the Nile Valley, coinciding with the emergence of food-producing societies in the region. Archeological and biological records suggest little differences in dietary habits and dental health during this transition. Furthermore, the substantial variations identified here would have happened in an extremely short time, a few centuries at most. This does not support in situ diet-related adaptation. Rather, we suggest these data are consistent with some level of population discontinuity between the Mesolithic and Neolithic samples considered here. Complex settlement processes could also explain the differences between Nubia and Central Sudan, and with previous results based on nonmetric traits.

Morphological Evaluation of Pear cvs. Santa Maria, Williams, and Deveci Grafted onto Clonal and Seedling Rootstocks

This research was conducted to determine the effects of quince clonal rootstocks [Quince BA29 (BA29) and Quince A (QA)], pear clonal rootstocks [FOX9, FOX11, OHxF333, OHxF87 and FAROLD40] and European pear seedling rootstocks on the morphological characteristics of 'Santa Maria', 'Williams', and 'Deveci' pear cultivars in Bafra (Samsun) ecological conditions in the research years of 2021 and 2022. Morphological characteristics, such as rootstock diameter (mm), trunk diameter (mm), trunk cross-sectional area (cm2), tree height (cm), crown dimensions (width, length, height and volume), leaf stalk length (cm), leaf stalk thickness (mm), leaf dimensions (width, length, area), annual shoot length (cm), node numbers and internode length (cm) were examined in the study. Results of the study revealed significant variation in the case of research years on most morphological attributes; generally, the values were higher in the research year 2022 than in 2021. It has been determined that the effect of rootstocks on all the morphological characteristics was significant except for leaf stalk thickness. The highest morphological values were obtained from OHxF333, FOX11, and FAROLD40 compared to the other rootstocks, and the lowest values were recorded in FOX9, OHxF87, and seedling rootstocks, respectively. Considering the cultivars' effect on the evaluated morphological traits, the highest leaf characteristics, and internode length in the annual shoots were acquired from the 'Santa Maria' cultivar, but all other attributes were higher in the 'Deveci' cultivar. The ' Williams ' cultivar recorded almost all the lowest morphological values. The highest trunk cross-sectional area was determined in the 'Deveci'/OHxF333 (38.63 cm2) and the lowest in the 'Williams'/FOX9 (4.95 cm2). The longest annual shoots were determined in the 'Deveci'/FOX11 (43.05 cm) and the shortest in the 'Williams'/Seedling (16.11 cm). The highest leaf area was observed from the 'Santa Maria'/BA29 (21.11 cm2) and 'Santa Maria'/FOX11 (20.95 cm2) combinations. According to the results of the research, it was determined that OHxF333 rootstock among the evaluated rootstocks performed morphologically better than the others. FOX9 and OHxF87 pear clone rootstocks showed very poor performance compared to other rootstocks.

Sex-specific effects of environmental temperature during gestation on fluctuating asymmetry in deciduous teeth.

External environmental heat exposure during gestation impacts the physiology of human development in utero, but evidence for these impacts has not yet been explored in dentition. We examined deciduous teeth for fluctuating asymmetry (FA), a measure of developmental instability, together with gestational environmental temperature data drawn from historical weather statistics. We measured dental casts from the longitudinal Burlington Growth Study, representing 172 participants (ages 3-6 years) with health records. FA was calculated from crown dimensions and intercuspal distances that develop during gestation. Multiple regression separated by sex (nfemale = 81) examined the effects of mean temperatures in each trimester, controlling for birth year. In females, increased temperatures during the first trimester are significantly associated with an increase in FA (p = 0.03), specifically during the second and third prenatal months (p = 0.03). There is no relationship between temperature and FA for either sex in the second or third trimesters, when enamel is formed. Dental instability may be sensitive to temperature in the first trimester in females during the scaffolding of crown shape and size in the earliest stages of tooth formation. Sexual dimorphism in growth investment strategies may explain the differences in results between males and females. Using enduring dental characteristics, these results advance our understanding of the effects of temperature on fetal physiology within a discrete period.

Estimation of Sex From the Buccolingual Dimension of Tooth Among the North Indian Population.

Identification is an important aspect of forensic medicine. Identification plays an imperative role, especially in highly decomposed bodies, mutilated bodies, and undisclosed and fragmentary human remains. The estimation of sex is an essential parameter of human identification. In forensic anthropometry, sex determination is related to morphometric characteristics of skeletal bones, such as the skull and mandible, clavicle, sternum, scapula, humerus, pelvic bone, sternum, and femur. Since teeth are decay-resistant, conscientious analysis of teeth can accredit reliable sex estimation of an individual, especially when other determinants are fragmented or destroyed. The aim of the study was to explore the association between sex and buccolingual crown dimensions of teeth. The study sample consists of 100 volunteer subjects (50 male subjects and 50 female subjects) aged between 20 and 35 years. Alginate was used to take impressions of the teeth and the cast was prepared using pouring by dental stone. Measurements of buccolingual parameters of all the teeth (except the third molars) of both jaws were done on dental casts by using a digital caliper. Collected data were analyzed using SPSS software (IBM Corp., Armonk, NY) and were outlined as mean and standard deviation (SD). The male and female groups were compared using an independent Student's t-test or unpaired test. The results of this study revealed that 16 out of 28 odontometric parameters (except third molar) of the two groups (male and female) were higher in the male group as compared to the female group (p < 0.05). Buccolingual odontometric parameters can be used for sex estimation in the North Indian population.

Experimental study of single droplet impingement on a thin liquid film under a non-uniform electric field

Droplet impingement on a thin liquid film has been extensively applied in the field of spray cooling due to its powerful heat and mass transfer properties. In this study, the impact dynamics of a single droplet impacting on a thin liquid film under a non-uniform electric field was experimentally investigated. Ethanol was employed as the working fluid, and the impact behaviors were captured by high-speed photography technology. The results showed that the impact process sequentially exhibits the phenomena of the liquid crown and liquid column. Five typical crown patterns were identified, and the unique “jet crown” mode was first reported. The crown dimension analysis indicated that the maximum crown height increased with the increase in electric Bond number (0 ≤ BoE ≤ 583.48), while the crown width was likely independent of BoE. Furthermore, this study provided the splashing threshold of the crown under a non-uniform electric field by coupling the BoE with an empirical formula determining the splashing threshold. In addition, a unique phenomenon of jetting liquid columns was obtained. During the ascent phase of the liquid column, the vertical downward acceleration of the liquid column was significantly greater than the gravitational acceleration. The presence of an electric field introduced fluctuations in the liquid column's acceleration, causing the direction of acceleration to alternate between upward and downward. This study contributes to a deeper understanding of the physical mechanisms underlying the electric field modulation of droplet impingement behavior.

Comparison between the average dimensions of three brands of stainless-steel crowns (SSCs) and the average dimensions of primary molar teeth

Background: Stainless-steel crowns (SSCs) are usually used for deciduous teeth with more than two destroyed surfaces. Selecting the suitable SSC, in terms of proximal fit and marginal fit, has usually been challenging for practitioners. The current study compares the deciduous molar dimensions in the SCCs with the dimensions of these teeth given in the textbook. Methods: The dimensions of 3M, Kids Crowns, and KTR SCCs were measured using a digital caliper. Utilizing SPSS 26 software, the data was examined and compared to the table of standard sizes of primary teeth using one-sample t test, ANOVA, and Tukey’s test. P values less than 0.05 were considered significant. Results: The study showed no significant difference in upper first molar SSCs in the occlusal-cervical dimension in Kids Crowns (P=0.14) and 3M (P=0.078) and in the mesiodistal dimension in Kids KTR (P=0.083) and Crowns (P=0.22). There was no significant difference in lower first molar SSCs in the occlusal-cervical dimension in Kids Crowns (P=0.14) and in the buccolingual dimension in 3M (P=0.91) and KTR SSCs (P=0.09). There was no significant difference in the upper second molar SSCs in the occlusal-cervical dimension of Kids Crowns (P=0.28) and 3M (P=0.32). There was no significant difference in lower second molar SSCs in the occlusal-cervical dimension in Kids Crowns (P=0.27) and KTR (P=0.07), in the mesiodistal dimension in Kids Crowns (P=0.22), KTR (P=0.22), 3M (P=0.59) and in the bucco-lingual dimension of KTR (P=0.26) and 3M (P=0.78). Conclusion: SSCs and teeth had the highest conformity in the occlusal-cervical dimension and the lowest conformity in the mesiodistal and bucco-lingual dimensions. SSCs had the highest conformity with the lower molars.

Fluorescence intensity of composite resin for direct veneer removal using a fluorescence-aided identification technique.

This laboratory study evaluated the influence of the fluorescence intensity of composite resins on additional tooth wear and the presence of restorative material in different dental thirds during the retreatment of direct veneers. The crown dimensions of 60 bovine incisors were reduced to 10 × 8 mm. The teeth were classified according to the fluorescence intensity of the composites: low (LOW) (TPH Spectra), medium (MED) (Opallis), and high (HIGH) (Essentia) groups. The teeth were divided according to the removal methods: conventional (CON) and fluorescence-aided identification technique (FIT). The specimens were scanned (T0), received veneer preparation, and scanned again (T1). After restorations, the composites were removed and the teeth were scanned (T2). Measurement assessments between T1 and T2 were performed to determine additional wear, presence of residual areas, and the average between additional wear and the presence of residual areas. Kruskal Wallis, Mann-Whitney, Friedman, 2-way ANOVA, and post-Tukey tests were performed (α < 0.05). The comparison of composite resins indicated a smaller area of additional wear and greater residue presence in the HIGH group than the LOW group for both techniques in the cervical third. Regarding removal methods, the FIT produced greater additional wear than the CON method for the LOW and MED groups in the middle and cervical thirds. The incisal third exhibited greater additional wear than the other thirds. Composite resins with high fluorescence intensity removed using FIT had less tooth wear. The incisal third was the most affected area for direct veneer removal procedures. A FIT has been proposed for composite resin removal; however, the different fluorescence intensities of composite resins can influence tooth wear caused during this procedure.

Digital measurement of deciduous tooth dimensions in China: A cross-sectional survey

ObjectiveCrown dimensions data of deciduous teeth hold anthropological, forensic, and archaeological value. However, such information remains scarce for the Chinese population. This multi-center study aimed to collect a large sample of deciduous crown data from Chinese children using three-dimensional measurement methods and to analyze their dimensions. DesignA total of 1592 children's deciduous dentition samples were included, and the sample size was distributed according to Northeast, North, East, Northwest, Southwest and South China. Digital dental models were reconstructed from plaster dental models. Independent sample t test, paired t test, principal component analysis (PCA), and factor analysis (FA) were used to analyze the tooth crown dimensions. Result18,318 deciduous teeth from 1592 children were included. Males exhibited slightly larger values than females. The range of sexual dimorphism percentages for each measurement was as follows: mesiodistal diameter (0.40–2.08), buccolingual diameter (0.13–2.24), and maxillogingival diameter (0.48–3.37). The FA results showed that the main trend of crown dimensions changes was the simultaneous increase or decrease in mesiodistal diameter, buccolingual diameter and maxillogingival diameter in three directions. ConclusionThis is the first large-scale survey of deciduous tooth crown dimensions in China, which supplements the data of deciduous tooth measurement and provides a reference for clinical application.

A model for predicting mean diameter at breast height from mean tree height and stand density

ABSTRACT Recent technological advances in airborne Light Detection And Ranging (LiDAR) allow the estimation of single tree or stand-level variables such as tree height and number of trees per hectare (stand density) for large area. However, it is impossible to measure the diameter at breast height (dbh) directly, and hence models have been proposed to estimate dbh indirectly from LiDAR-derived tree height and/or crown dimensions. This study develops a model for predicting mean dbh (D) from mean tree height (H) and stand density (ρ). To derive the model, we assumed (1) the conservation rule of stem surface area, (2) the power relationship between relative density by stem surface area and relative spacing index, and (3) the linear relationship between stem surface area and the product of tree height and dbh. This model was applied to Japanese cedar (Cryptomeria japonica D. Don) and Japanese cypress (Chamaecyparis obtusa Endl.) plantations throughout Japan, and its predictive performance was assessed using field-based forest inventory data. The results showed that D could be successfully estimated from H and ρ, although it was underestimated when D was greater than 40 cm. The model can be easily applied not only to other conifer species and districts but also to other remote sensing studies.

Temporal Dynamics of Tree Crown Fractal Dimension in Two Species of Deciduous Oaks

Fractal dimension (D) can be used to characterise temporal changes of crown architecture of individual trees. Our goal in this study was to analyse seasonal changes in tree crown fractal dimension of two species of deciduous oaks (Quercus castanea and Q. obtusata) coexisting in a natural forest in central Mexico using low cost sampling, and relate these changes to morphological attributes and environmental variables.Every two months, from May 2017 to September 2018, for each oak species, we photographed fixed portions of the crowns of individual trees, measured their trunk diameters, and obtained average temperature and accumulated precipitation data recorded for the sampling date. From the obtained images, we calculated D values by the semivariogram method using three different variability estimators (square increment, isotropic, and transect variation).We identified a positive correlation between D and temperature, and a negative correlation between temperature and crown cover.The fractal dimension (D) of crowns of two deciduous oak species changes according to the tree’s phenological stage. D values varied through time in relation to tree crown phenological variation, but not with crown cover dimension. We propose a model of annual D value fluctuation in deciduous trees, characterised by two high complexity peaks and two low complexity valleys, corresponding to the effects on crown cover of annual periods of leaf abscission and development.

Constructing a non-linear additive crown-width model system for moso bamboo forests in eastern China

ABSTRACT Tree crown can be described by various crown dimension variables, including crown width (CW), an important predictor variable in forest growth-and-yield models. Because CW is quantified as the arithmetic mean of north–south and east–west CW measurements (crown components), issues of additivity and inherent correlation between crown components exist. Using two versatile estimation algorithms (non-linear seemingly unrelated regression − NSUR – and non-linear error-in-variable models − NEIVM), we employed three methods of constructing simultaneous model systems (non-linear summation − NSE, one-step proportional weighting system − OPWS, and two-step proportional weighting system − TPWS) to effectively address those issues. The performance of the three methods was evaluated using CW measurements of moso bamboo (Phyllostachys edulis) in China. Results showed that the OPWS outperformed the NSE and the TPWS for each algorithm. NEIVM-OPWS was more accurate than TPWS, and NEIVM outperformed NSUR. Diameter at breast height, total height and mean diameter at breast height (a variable describing stand density and competition) significantly contributed to CW and its component equations. Each CW model system included additivity of the crown component equations and accounted for the inherent correlations between equations. Overall, NEIVM-OPWS provided a closer estimate of CW to the measured CW than other model systems and methods employed. An effective CW model system will help understand light capture by the bamboo canopy and contribute to the effective management of bamboo forests in China and elsewhere.

Dimensions of crowns and their level of productivity of apple trees of the Jonaweld variety depending on the method and term of crown pruning

Dimensions of crowns and their level of productivity of apple trees of the Jonaweld variety depending on the method and term of crown pruning

Teak‐Soil Interaction: Teak (Tectona grandis) Plantations Impact and are Impacted by Soil Properties and Fertility in Southwestern Ghana

Teak (Tectona grandis) is one of the most widely established plantation species globally due to its potential for degraded forest restoration, timber supplementation, and easing pressure on natural forest resources. However, the extent to which plant‐soil interactions in teak plantations impact tree growth and productivity and soil nutrient dynamics is not well understood. This study assessed the impact of teak plantations on soil physicochemical properties as well as the influence of soil properties and fertility on teak growth. The study was conducted in teak plantations aged 5, 10, 15, 20, and over 20 years and an adjacent natural forest remnant. We established three 25 m × 25 m plots in each teak plantation and recorded the diameter at breast height (DBH), height, crown length, and depth of all trees. We collected 54 soil samples at 0–20 cm depth and analysed them for 29 soil parameters. The study revealed that teak plantations resulted in a decline in soil N (45%–81%) and available P (63%–98%) concentration, while soil pH improved by 0.41–0.64 units. However, soil organic carbon, K, Mg, Ca, and Na concentrations and their ratios were unaffected with teak plantations over time. Also, soil textural characteristics, acidity, and nutrient ratios were observed to influence tree‐related characteristics such as DBH and crown dimensions (crown, diameter, breadth, length, and volume). Three principal components (PC1, PC2, and PC3) explained 69% of the overall variability and were significantly related to tree crown parameters, height, and diameter at breast height. We concluded that site selection and tailored integrated soil fertility management for each plantation age are critical to sustainable teak production as teak plantations both affect and are affected by soil properties. The study recommends the adoption of management practices aimed at maintaining soil nutrient balance to ensure the long‐term growth and ecological sustainability of teak plantations.

Analysis of Gender Dimorphism and Assessment of Racial Variation Through Odontometric Technique: A Cross-Sectional Study.

When conducting a forensic investigation, one of the most important steps is establishing the biological profile of a victim who cannot be positively recognized or is just a skeleton. It has been shown that, among the other clinical indicators, the diameters of dental crowns are a good and dependable source for determining gender in a particular population sample. However, the literature is sparse regarding their assessment as a viable marker for the determination of a particular race. In addition, the need for population-specific data has also been advocated while determining gender dimorphism based on tooth size. To study the bisexual variation in the permanent dentition of individuals from three different sets of populations: Arabian, South Asian, and East Asian. The other objective is to explore the role of this odontometric analysis in predicting the racial identity of the subjects belonging to the aforementioned population. The research was conducted at the College of Dentistry, AlJouf University in Sakaka. Measurements of mesiodistal and buccolingual (BL) distances were taken using a digital vernier caliper on a total of 75 pairs of research models or casts. Statistical tests were run on the information gathered. Of the 75 casts, 38 (50.7%) were of male and 37 (49.3%) were of female. Our analysis showed between genders, a significant difference in maxillary central incisor (P = 0.001), first premolar (P = 0.01), and first molar (P = 0.02) while for a mandibular arch, a significant difference was noted for incisors (P = 0.002) with greater tooth dimension in male than in the female. Concerning the BLdimensions, only the mandibular canine showed a significant difference between males and females (P = 0.001). Comparisons of the crown dimensions between population groups showed that the Arabian population consistently exhibits larger tooth dimensions than the other two populations in both arches. A few crown dimensions can be used as an adjunctive tool for the identification of the gender and race of an individual.

A Photographic Assessment of Smile by Modifying Crown Height, Width and Angulation of Maxillary Lateral Incisor among Orthodontic Patients of Karachi, Pakistan

Abstract: Background: Smile aesthetics vary culturally, influenced by media and the Golden Proportion in dental beauty. Challenges arise with missing lateral incisors, treated through composite build-up or canine substitution, highlighting the importance of crown dimensions and the need for clinician expertise in personalized treatments. Objectives: The objective of the study is to evaluate the influence of altering height, width and angulation of maxillary lateral incisors on the perception of smile. Materials and Methods: This cross-sectional study was conducted at OPD of Jinnah Medical and Dental College, Karachi from January 2020 to June 2020, on 120 orthodontic patients (44 males and 76 females) aged between 15 and 35 years. Photoshopped photographs of an ideal smile were shown to the participants. In an ideal smile photo, the width of lateral incisor was 62% of the width of maxillary central incisors. The pictures showed to the participants had modifications in terms of crown heights, width and angulation of only maxillary lateral incisor without doing any changes to the other maxillary teeth. The responses of the participants were graded on the basis of perception of attractiveness. Result: Mean score for height, width and angulation changes were obtained. The highest score by males was given to lateral incisor whose length was increased by 1mm (6.87±2.21) and in females; the highest score was given to lateral incisor which is modified by adding 0.5 mm increment (6.98±1.05). Both males and females preferred narrow lateral incisors as esthetically attractive. The mean highest scores for the decrease in width given by males were 6.52±2.52 and 6.8±2.217 by females, respectively. Both males (6.37±2.18) and females (6.64±1.81) preferred 10 degrees of mesial angulation of lateral incisor as more esthetically pleasing. Changes in distal angulation of more than 5 degrees are considered unattractive by both genders. Mean values were 6.04±2.15 for males and 6.00±1.99 for females. Conclusion: In conclusion females are more concerned to the change in height, while in terms of width both genders preferred narrower maxillary lateral incisors over wider ones. Both genders perceived a 10 degree mesially angulated lateral incisor as more attractive.

Density affects plant size in the Gobi Desert

Plant size is a crucial functional trait with substantial implications in agronomy and forestry. Understanding the factors influencing plant size is essential for ecosystem management and restoration efforts. Various environmental factors and plant density play significant roles in plant size. However, how plant size responds to mean annual precipitation (MAP), mean annual temperature (MAT), and density in the arid areas remains incomplete. To address this knowledge gap, we conducted comprehensive vegetation surveys in the Gobi Desert in northwestern China with a MAP below 250 mm. We also collected climate data to disentangle the respective influences of climate and density on the community-weighted plant height, crown length, and crown width. Our observations revealed that the community-weighted mean plant height, crown length, and width demonstrated a positive association with MAT but negative relationships with both MAP and density. These patterns can be attributed to the predominance of shrubs over herbs in arid regions, as shrubs tend to be larger in size. The proportion of shrubs increases with MAT, while it decreases with MAP and density, resulting in higher plant height and larger crown dimensions. Although both MAP and MAT affect plant size in the Gobi Desert, our findings highlight the stronger role of plant density in regulating plant size, indicating that the surrounding plant community and competition among individuals are crucial drivers of plant size patterns. Our findings provide valuable guidance for nature-based solutions for vegetation restoration and ecosystem management, highlighting the importance of considering plant density as a key factor when designing and implementing restoration strategies in arid areas.