Crown Length Research Articles

Potassium fertilization in pineapple fruit quality

Abstract Potassium is a mineral nutrient that affects the growth and quality of pineapple fruits. This study aimed to evaluate the quality of ‘Vitória’ pineapple fruits submitted to application of potassium doses. The experiment was carried out from May 2017 to November 2018, in the municipality of São Francisco do Itabapoana (RJ), Brazil. The design was randomized blocks, with four replicates. Treatments were five K2O doses: 0; 6; 12; 18 and 24 g plant-1, applied as KCl, split into two applications after flower induction. Fruit and crown fresh masses, fruit and crown diameters, fruit and crown lengths, titratable acidity, soluble solids, vitamin C, juice pH and soluble solids/titratable acidity ratio were evaluated. Potassium fertilization promoted greater fruit length, diameter and mass. Titratable acidity, soluble solids and vitamin C values increased linearly as a function of potassium doses. Potassium fertilization improves the quality of ‘Vitória’ pineapple fruits under field conditions.

Enhancement of the technology of mining steep ore bodies applying the “floating” crown

When mining ore bodies in Kryvyi Rih iron ore basin, underground mines apply open stoping or bulk caving systems in proportion of 55% to 45%. Most of underground mines prefer stoping with pillar caving. Yet, rock pressure contributes to growth of costs for workings maintenance and deterioration of extraction indices. Rock mass extraction indices can be enhanced by application of a protectve structure in the upper part of the block that will enable additional decrease in load on the draw level. There are a great many of methods for determining parameters of constructive elements of the protective structure that help keep its integrity for the whole period of block mining. The article suggests methods for determining parameters of the protective structure when mining steep ore bodies. The research conducted demonstrates that with the inclined protective structure, increase of unit load on it from 200 to 1200t/m2 leads to decrease of its thickness from 6.3-20.9m to 5.5-18.4m and increase of the crown length from 40m to 60m. The developed block caving system with application of the protective structure when mining steep ore bodies enables overall decrease of ore dilution in the block by 3%, increase of iron content in the mined ore by 1.3% without significant mining costs growth and decrease of loads on the workings of the receiving level.

Long-term tending effect on static stability of pure beech (Fagus sylvatica L.) stands

The production stability together with the provision of required functions are the key requirements for the future existence of stable forest stands. Sufficient mechanic stand stability could be developed by the early and long-term thinning where basic tree characteristics, such as stem and crown parameters play the decisive role. We compared selected parameters of static stability in pure beech stands, which have been exposed to heavy low thinning and free-crown thinning with control stands without interventions. Data from twenty-seven long-term research subplots at eight localities across Slovakia were involved in this study. In total 7 693 trees between 30 and 110 years were analysed. Slenderness (h/d ratio), crown length, crown width and crown ratio proved to be the most explanatory parameters for the defining mechanical stability on subplots with free-crown thinning. We found the least favourable results on control subplots. The differences between the subplots with tending (regardless of the tending method) and the control subplots were statistically significant in all studied parameters (P < 0.05).

Crown Lengthening Procedure: Report of Two Cases

Crown lengthening is a surgical procedure designed to increase the extent of the supragingival tooth structure, so that the clinician can restore the tooth. Crown lengthening procedure is done to maintain normal biologic width and increase crown length for retention of prosthesis. Various techniques have been proposed to perform CLP, such as gingivectomy, undisplaced flap with or without osseous reduction, apically repositioned flap with or without bone reduction, and orthodontic forced eruption with or without fibrotomy. Selection of one of this CLP technique depends upon esthetics, clinical ratio of crown to root, structure of root, location of furcation, position of tooth and the capacity of the tooth to be restored. This case report illustrate two different methods of doing crown lengthening procedure the selection of case depends upon various soft tissue and hard tissue parameters. Owing to the various advantages, disadvantages and associated limitation with different methods, we opted for surgical CLP with scalpel method. Uneventful healing was observed in both our cases. No post-operative complications was observed in both cases. Thus to conclude success rate of CLP is high but appropriate selection of case is required. In our case report both the methods of CLP shows significant result in increasing the crown length and maintaining the biological width.

Mixing effects on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) productivity along a climatic gradient across Europe

Mixed-species stands have been found to be more productive than would be expected from the performance of their component species in monocultures due to facilitation and complementarity between species, although these interactions depend on the combination of species present. Our study focuses on monospecific and mixed-species stands of Scots pine and Norway spruce using 20 triplets established in nine countries along a climatic gradient across Europe. Differences in mean tree and stand characteristics, productivity and stand structure were assessed. Basal area increment in mixed stands was 8% higher than expected while volume increment was only 2% greater. Scots pine trees growing in mixed-species stands showed 11% larger quadratic mean diameter, 7% larger dominant diameter, 17% higher basal area and 25% higher stand volume than trees growing in monospecific stands. Norway spruce showed only a non-significant tendency to lower mean values of diameters, heights, basal area, as well standing volume in mixtures than monocultures. Stand structure indices differed between mixed stands and monocultures of Scots pine showing a greater stratification in mixed-species stands. Furthermore, the studied morphological traits showed little variability for trees growing in monospecific stands, except for diameter at breast height, crown length and crown length ratio. For trees growing in mixed stands, all the morphological traits of the trees were identified as different. Some of these morphological traits were associated with relative productivity. Nevertheless, relative productivity in mixed-species stands was not related to site conditions.

Maxillary anterior root resorption in Class II/I malocclusion patients post fixed orthodontic treatment

Background: Previous studies on root resorption were reviewed by panoramic radiographs. Cone-beam computed tomography (CBCT) showed that 41.5% of teeth experienced resorption when panoramically examinated, while 68% of teeth experienced resorption when the examination method used was CBCT. Root resorption occurs in the maxillary central incisor (as much as 74%) and in the maxillary lateral incisor (as much as 82%). The maxillary canines have the most resorption, followed by the lateral maxillary incisors. Purpose: The aim of this study was to determine the differences of apical resorption in anterior maxillary teeth before and after orthodontic treatment in skeletal Class I/II cases of extraction. Methods: Samples from this study were the results of panoramic photographs of 50 patients treated by fixed orthodontic appliances at the Dental and Oral Hospital Airlangga University. These were selected according to the sample criteria. The evaluation method consists of measuring root and crown lengths with a digital application (RadiAnt DICOM Viewer). Subsequently, the measurements were evaluated using CBCT images. Results: The data were statistically analysed using normality tests with Shapiro–Wilk and Kolmogorov–Smirnov tests. Based on the results of paired sample tests, it was found that every treatment group had significant differences in the average length of the crowns and roots, with a result of p=0.000 (p<0.05). Conclusion: The use of CBCT is considered quite effective and accurate in evaluating root resorption compared to panoramic photographs.

Visible Portion of Anterior Teeth at Rest and Analysis of Different Smile Characteristics in the Saudi Population of the Jeddah Region.

This cross-sectional study aimed to determine the degree of visibility of maxillary and mandibular anterior teeth at rest in different age groups and to evaluate the smile line, smile arc, and number of maxillary teeth displayed during smiling among the Saudi population visiting King Abdulaziz University Dental Hospital, Jeddah, Saudi Arabia. A total of 157 participants (77 males and 80 females) were included in this study with an age range of 19 to 69 years. All participants had maxillary and mandibular anterior teeth without restorations. Crown length and visible portions of anterior teeth at rest were measured using a Fowler Electronic Digital Caliper. Three measurements of each variable were recorded by two independent dental interns and calibrating their measurements was performed. Smile line, smile arc, and number of teeth displayed during smiling were examined. The collected data were statistically analyzed using SPSS software. It was found that the average clinical crown lengths in the maxillary lateral incisor, mandibular central incisor, and canine were significantly higher in males than females. At rest position, females displayed more maxillary central and lateral incisors. The displayed length of maxillary teeth at rest is inversely proportional to increasing age; the reverse occurs in mandibular teeth. The common visibility of maxillary teeth during smiling was from the second bicuspid to its counterpart. Average smile line and consonant smile arc were the most common characteristics. It was concluded that both age and gender affect the characteristics of tooth display at rest and in smiling. These effects should be considered during treatment planning and restoration of anterior teeth to obtain a more predictable esthetic outcome.

Stable Allometric Trajectories in Picea abies (L.) Karst. Trees along an Elevational Gradient

The effect of temperature on tree phenology and growth has gained particular attention in relation to climate change. While a number of reports indicate that warming can extend the length of the growing season and enhance tree growth rates, it is still debated whether temperature also affects biomass partitioning. Addressing the question of whether trees grown at different elevations invest similarly in various organs, we established four sites along an elevational gradient (320 to 595 m a.s.l.) in managed Norway spruce (Picea abies (L.) Karts) stands regenerating after clearcuts in central Norway. There, differences in temperature, bud break, tree growth, and allometric scaling were measured in small spruce trees (up to 3 m height). The results showed that bud break and shoot growth are affected by temperature, as lower sites completed the bud break process 5 days earlier than the higher sites did. There was some evidence indicating that the summer drought of 2018 affected tree growth during the season, and the implications of this are discussed. The allometric scaling coefficients did not change for the crown volume (slope value range 2.66–2.84), crown radius (0.77–0.89), and tree diameter (0.89–0.96) against tree height. A slight difference was found in the scaling coefficients of crown length against tree height (slope value range 1.04–1.12), but this did not affect the general scaling of the crown volume with tree height. Our results showed that different local environmental conditions affect both the growth rate and phenology in Norway spruce trees but, on the contrary, that the biomass partitioning among different parts of the tree remains essentially unchanged. This demonstrates that the allometric approach is an important tool for unraveling true vs. apparent plant plasticity, which in turn is an essential awareness for predicting plant responses to environmental changes.

Influence of neighbor competition and tree attributes on the fruit production of Sinomanglietia glauca, an endangered tree species endemic to China

Sinomanglietia glauca is a critically endangered species with limited population and narrow distribution in China. Yet to date, we know surprisingly little about how the characteristics of forests affect the reproduction process of S. glauca individuals. The fruit production of S. glauca individuals was examined in artificial forest (AF), free-encroached deciduous forest (FF), and intensively encroached forest by evergreen trees and moso bamboos (EF) at Mingyueshan Mountain in Jiangxi province. The relationships between the characteristics of fruits and seeds and those of parent trees and neighborhood were analyzed through redundancy analysis. The fruiting indicators (number, weight and volume of fruits/seeds) for S. glauca in AF were significantly higher than those in EF and FF. The fruit production was positively related to the crown radius and the ratio of crown length to tree height, and was negatively linked to neighbor enclosure index. The characteristics of parent trees, neighborhood and their interaction explained the variation of fruit production by 70.6%. Although the competition of neighbors exerted less explanatory power than the characteristics of parent trees, it was negatively correlated with the crown radius and volume. The crown radius and neighbor enclosure were identified as the two dominant causal factors taking the major responsibility to the fruit production. The increasing competition from neighbors bring detrimental impacts on the fruiting of S. glauca. Efficient management strategies were proposed to reduce the interference from neighbors, such as reasonably pruning and thinning adjacent evergreen trees and bamboos.

Prevalence of different methods of crown lengthening and its preference among dental specialties

Short clinical crowns often lead to poor retention form, leading to improper tooth preparation. Crown lengthening is carried out to increase the clinical crown length without violating the biologic width. Several techniques have been proposed for crown lengthening such as gingivectomy procedures. A Cross-sectional, descriptive study was conducted in a university, on randomly selected individuals. The study group consisted of patients getting treated at the Department of Prosthodontics from June 2019 – March 2020. 86,000 case sheets were reviewed, and samples were selected using simple random sampling. The two variables were compared using the chi-square test. Laser gingivectomy was the most common 55.9% form of crown lengthening procedure. Awareness of crown lengthening was found more among postgraduates at 78.7%. Among all the departments, crown lengthening was required more for periodontal procedures 42.3%. In this era of quickly developing technologies and innovative ideas, the requirement for faster treatment has not only become a requirement but a necessity. Treatment with lasers is well accepted by patients as it is less time-consuming and painless. Lasers have taken over a lot of procedures so is crown lengthening. Postgraduates know more about crown lengthening and hence do in more number of cases. There are various reasons to get crown lengthening done with periodontitis being the most common specialty for its need.

One‐ versus two‐stage crown lengthening surgical procedure for aesthetic restorative purposes: A randomized controlled trial

This randomized controlled trial aimed to assess the efficacy of a two-stage crown lengthening intervention (SCL) in the aesthetic zone compared with a one-stage crown lengthening procedure (CCL). Thirty subjects were randomly assigned to either SCL (n=15) or CCL (n=15) groups. SCL consisted of full-thickness flaps followed by bone recontouring and gingivectomy 4months postoperatively, if required. In CCL, osseous recontouring after submarginal incisions was performed, followed by flap repositioning. Records were obtained at baseline, 4months (only in SCL), 6months and 12months. Primary outcome was the precision in achieving a pre-determined gingival margin position. Other outcomes considered were changes in the gingival margin position and keratinized tissue width (KTW) at 12months, and patient-reported outcomes (PROMs). Surgical precision was comparable between groups (0.2±0.4mm in the CCL group and -0.2±0.5mm in the SCL group). Four patients in the SCL group (27.7%) did not require a second-stage surgery. KTW was significantly higher in the SCL group (6.3±1.4mm versus 5.0±1.4mm, p=0.017). SCL resulted in a lower impact on quality of life when compared to the CCL group. Both approaches were highly accurate obtaining the desired crown length. SCL was associated with a lower reduction in KTW and more favourable oral health-related quality of life (OHIP-14).

Study of the oil palm crown characteristics associated with Basal Stem Rot (BSR) disease using stratification method of point cloud data

Basal Stem Rot (BSR) disease caused by the Ganoderma boninense fungus is the most serious issue affecting the oil palm industry. Terrestrial laser scanning (TLS) technology is a precise, contact-free, and active remote sensing method which is widely used for determining tree morphology using the crown strata. However, its capability in BSR detection using crown strata solely has not been explored. Therefore, this study used TLS data to study the effect of crown profile due to BSR and develop a BSR detection model using crown strata. Ninety-two palms were selected at random consists of 36 healthy oil palm trees and 56 unhealthy oil palm trees infected by Ganoderma boninense. The palms were each scanned at four different positions around them, and crown strata (named as Cn; where n is the crown length in cm) were generated using crown stratification method. The numbers of laser hits in the strata were used to generate crown profiles comparing healthy and unhealthy oil palm trees, to develop prediction models and to examine the patterns of crown density in different parts. The study has accounted for the occlusion problem by carrying out a systematic multi-scan approach. Moreover, the short traveling distance (less than 12 m) needed for the laser to reach the maximum crown tips ensures greater point density. The profiles of crown strata revealed that the healthy trees have higher crown densities than unhealthy trees starting from 250 cm from the top (strata no. 5) to the bottom. Prediction models using the strata parameters C650, C700, C800, and C850 were 92.5% accurate in the classification of healthy-unhealthy trees.

Influence of Different Thinning Treatments on Stand Resistance to Snow and Wind in Loblolly Pine (Pinus taeda L.) Coastal Plantations of Northern Iran

Loblolly pine (Pinus taeda L.) is one of the main exotic conifer species that has been widely planted for the past fifty years for timber production in the coastal areas of northern Iran. Heavy snowfall and strong winds can cause much damage to these forests over a short time span of only a few years. This study was conducted to estimate snow and wind damage and analyze the role of stand thinning in their resistance to snow and wind. Amount and type of snow and wind damage were examined through systematic (80 m × 80 m) sample plots (each plot area of 625 m2) in nine different stands (2–10 plots in each stand) in terms of age, structure, and silviculture history in three replications for each stand in April and May 2020. Results showed that the amount of snow and wind damage had a wide range from 1.3% to 30.7%. Snow damage was more than three times that of wind. Snow and wind damage in the young stands were significantly more serious (p < 0.01) than in the middle-aged and old stands, and damage was significantly higher (p < 0.01) in the unthinned stands than in the thinned ones. Slenderness coefficient (Height/Diameter ratio, HD ratio) of trees resulted to be a good indicator in young and middle-aged stands, while crown form indices (relative crown length and relative crown width) were acceptable indicators in old stands for risk of snow and wind damage. Our results showed that the normal thinning (15% of basal area) decreased snow and wind damage in all the stands, while the heavy thinning (35% of basal area) reduced the snow damage, but it increased the wind one. It is possible to recommend high intensity thinning in young stands, normal thinning in middle-aged stands, and light thinning (15% of basal area) in old ones.

External Root Resorption after Orthodontic Treatment with Invisalign®: A Retrospective Study

AIM: To measure the incidence and severity of root resorption after orthodontic treatment with Invisalign.
 
 MATERIAL AND METHODS: This retrospective study was conducted at Riyadh, Saudi Arabia from June 2017 to January 2018. Pre- treatment and post-treatment Orthopantographs were obtained from orthodontic records of 29 patients managed with aligners (Invisalign®, Align Technologies, Santa Clara, CA, USA) at different dental clinics in Riyadh City. The selected sample was fulfilled the following criteria: (1) Class I malocclusion, (2) Mild to moderate crowding, (3) Non-extraction orthodontic treatment, (3) No evidence of root resorption before orthodontic treatment, (4) No root abnormalities or dilaceration, and (5) Good quality of pre- and post-treatment Orthopantographs. One examiner performed the measurements directly on the Orthopantographs using electronic digital caliper (Mitutoyo Manufacturing Co. Ltd., Tokyo, Japan) with an accuracy of 0.01mm. The measurements were performed on maxillary and mandibular central incisors, lateral incisors, and canines pre- and post-operatively, resulting in a total of 696 measurements. The crown length was measured from incisal edge to cemento- enamel-junction, while the root length from cemento-enamel-junction to root apex.
 
 RESULTS: In our study, 72% of the teeth demonstrated root resorption, in regard to the severity of root resorption, we found that mild root resorption > 0% up to 2% in all the affected teeth. Upper Anterior teeth have more significant resorption rate than lower anterior teeth P<0.05.
 
 CONCLUSION: The present study showed that incidence of root resorption was high after orthodontic treatment with Invisalign®, however the severity is very low and it is limited to the surface resorption only.

Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating

The impingement of ethanol droplet train on the heated titanium substrates without or with the titanium oxide nanotube coating has been experimentally investigated in close view. The coating makes the substrate with high wettability. Four distinct but steady hydrodynamic patterns are observed on both two surfaces, namely, liquid aggregation and crown periphery instability; sub-droplet splashing and crown periphery instability; splashing and stable crown; and splashing with stable angle. However, the more wetting nanotube coated substrates push the transition between the patterns to a higher temperature. The quantitatively analysis of spreading length, diameter and height of crown and stable splashing angle further proved the transitions between the hydrodynamic patterns on the two titanium surfaces. The instability at the crown periphery may result from the low surface tension of the working fluids in first and second patterns, while the crown becomes stable on the third pattern. In the fourth pattern, a sharp shift of the splashing angle from decreasing to increasing is found at the surface temperature of 323 ∘C and 404 ∘C for the bare titanium surface and the nanotube coated surface, respectively. The shift could be attributed to the emergence of Leidenfrost effect. It is found that the Leidenfrost point at the droplet train impingement on the nanotube coated surface has been remarkably delayed.

Association of Fetal Nasal Bone Length And Gestational Age Between 14-28 Weeks of Pregnancy

Nasal bone (NB) is a significant structure to be assessed during pregnancy in 1st and 2nd trimesters. Nasal bones that start to grow as neural crest cells (NCCs) collections, can histologically be confirmed when length of fetal crown–ump is 42mm (10.9 weeks).

Clinical Quantitative Evaluation of Tooth Wear: A 4-year Longitudinal Study.

This study investigated the progression of incisal tooth wear clinically for 4-years, using various diagnostic methods. Effectiveness of occlusal splints (night guards) for patients with nocturnal bruxism was also evaluated. Forty maxillary incisors from 10 patients with nocturnal bruxism were selected. Group 1 (n=5) wore occlusal splints for 6 months, whereas group 2 (n=5) didn't. Ultrasound, cast-model analysis (control), digital radiography, FluoreCam and colorimeter were used for measurements. Clinical progression of incisal wear monitored at baseline, 3, 6, 12, 24 and 48 months, respectively. Ultrasound, cast-model analysis and FluoreCam readings gradually and statistically significantly decreased during the overall evaluation period for both groups (p<0.001). Regarding colorimeter, statistically significant differences in periodical measurements were observed from 24 months and 12 months, for group 1 and group 2, respectively (p<0.001). There were no statistically significant differences in readings at evaluation periods, between the groups, for ultrasound, digital radiography and cast-model analysis (p≥0.05); however, statistically significant differences were observed for colorimeter at 24 months (p=0.010) and 48 months (p<0.001), and for FluoreCam at 12, 24, 48 months (p<0.001). Annual decrease in mean crown length was determined as 20-30 µm for group 1 and 40-50 µm for group 2. The decreases in mean crown length were statistically significantly lower for group 1 compared to group 2, regarding the assessments for 1 year, 2 years and 4 years (p<0.001). Positive and good correlations were observed between ultrasound, cast-model analysis and FluoreCam measurements (p<0.001). Ultrasound, FluoreCam and colorimeter showed promising results for monitoring any change and progression of incisal tooth wear clinically. Ultrasound might be considered as a quantitative, reliable and repeatable method. Precision of the measurements varied among the diagnostic methods used. Occlusal splints may have a potential preventive effect for progressive tooth wear.

Response of black alder (Alnus glutinosa (L.) Gaertn.) to selective thinning of various intensities

Područje poplavnih šuma crne johe (Alnus glutinosa (L.) Gaertn.) u Sloveniji čini samo 0,4 % (približno 4708 ha) ukupne površine šumskog zemljišta (Čater i sur., 2001.). Veći kompleks takvih sastojina u Sloveniji su Črni i Polanski Log, a istraživanje je provedeno na području potonjeg (slika 1). Kako čiste sastojine johe odlikuju brojne specifičnosti, potrebno im je prilagoditi šumskouzgojne postupke. Da bi se utvrdio odgovarajući intenzitet prorjede takvih sastojina, 1967. godine u Polanskom Logu postavljene su pokusne plohe. Od tada do 2018. godine na plohama je izvršeno pet do sedam mjerenja. Sva stabla na plohama su bila obrojčana. Izvršeno je mjerenje prsnih promjera i procjena sljedećih elemenata na stablima: pripadnost etaži, vitalnost, uzgojna perspektiva, uzgojna uloga, duljina krošnje i kvaliteta (tablica 3). Svaka ploha bila je podijeljena u tri polja (40 x 50 m) s različitim metodama rada: bez intervencije, umjereno i intenzivno prorjeđivanje. Uzgojni postupci koji su poduzeti tijekom praćenja pokusa prikazani su u tablici 2. Danas su te sastojine u zreloj fazi razvoja, stoga smo u ovom radu analizirali reakcije crne johe na različite intenzitete prorjeđivanja i dobivene rezultate usporedili s preporukama autora tradicionalnih uzgojnih modela i modela koji se temelje na situacijskoj njezi šuma. Ustanovili smo da se na plohama s intenzivnim prorjeđivanjem gustoća sastojine koja je u dobi između 50 i 70 godina i na kraju je ophodnje kreće od 295 do 690 kom/ha (slika 3), dok se na plohama bez intervencije ova vrijednost kreće u rasponu od 370 do 790 kom/ha. Drvne zalihe u istom su se razdoblju kretale u rasponu od 277 do 458 m&lt;sup&gt;3&lt;/sup&gt;/ha na plohama s intenzivnim prorjeđivanjem, dok su na plohama bez intervencije bile veće, u rasponu od 309 do 516 m&lt;sup&gt;3&lt;/sup&gt;/ha (slika 4). U to su se doba temeljnice nalazile u rasponu između 23 i 41 m&lt;sup&gt;2&lt;/sup&gt;/ha na plohama s intenzivnim prorjeđivanjem, a na plohama bez intervencije u rasponu od 26 do čak 51 m&lt;sup&gt;2&lt;/sup&gt;/ha (slika 5). Tijekom cijelog razdoblja praćenja ploha, stabla su, bez obzira na metodu rada, narasla za tri do četiri debljinska stupnja (slika 2). Na plohama s umjerenim prorjeđivanjem i onima bez intervencije, debljinski prirast stabala bio je skoro jednak (0,33 cm godišnje) (slika 6). Statistički je značajan veći debljinski prirast stabala na plohama s jako intenzivnim prorjeđivanjem (0,37 cm godišnje). Debljinski prirast dominantnih stabala bio je nešto veći, od 0,46 cm godišnje na plohama bez intervencije do 0,50 cm godišnje na plohama s jako intenzivnim prorjeđivanjem, ali statistički značajne razlike između metoda rada nisu utvrđene (slika 6). Međutim, otkrili smo da kod dominantnih stabala ne postoje statistički značajne razlike s obzirom na njihovu slojevitost, vitalnost, tendenciju, dužinu krošnje i kvalitete s obzirom na korištenu metodu rada. U usporedbi s uzgojnim modelima koji su se koristili za manji broj odabranih stabla, gustoća i temeljnica ispitivanih sastojina je znatno veća, a debljinski prirast manji. Autori tradicionalnih i modela s manjim brojem odabranih stabala zagovaraju rano prorjeđivanje takvih sastojina (tablica 1). Veće razlike nastaju u konačnom broju stabala po hektaru i u intenzitetu intervencije. Razlog malog debljinskog prirasta i razlike između metoda rada na našim plohama pripisali smo nedovoljnom intenzitetu i djelomično nedosljednoj provedbi postupka prorjeđivanja. Ipak, ukazala se potreba za intenzivnim prorjeđivanjem i pospješivanjem rasta stabala najvećeg prsnog promjera, vitalnosti i tendencije, lijepo oblikovane i duge krošnje (slika 7, slika 8).

Relationship Between Crown to Root Ratio and Alveolar Bone Support in Patients With Unilateral Cleft Lip and Alveolus.

To evaluate the tooth lengths, crown to root ratios (CRRs), and alveolar bone support (ABS) around cleft-adjacent maxillary central incisors (U1s) in patients with unilateral cleft lip and alveolus (UCLA) and to investigate the relationships between CRR and ABS. This is a retrospective study. Cleft Lip and Palate Care Center of Shanghai Ninth People's Hospital, Shanghai, China. Fifty-eight Chinese patients with UCLA. Cone beam computed tomography data from 58 nonsyndromic patients with UCLA (36 males, 22 females; mean age = 12.65 ± 3.64 years) were evaluated. Crown length and root length, alveolar bone thickness (ABT), and the distances between the cementoenamel junction and alveolar bone crest on 4 surfaces of cleft-adjacent U1 were measured and compared with those of noncleft side in the same patients. Crown to root ratio and frequency of dehiscence were calculated and comparisons were also made between cleft and noncleft sides. Regression analysis was performed to explore the association between CRR and ABS. The CRR of cleft-adjacent U1 and alveolar bone crest heights (ACHs) on the 4 surfaces were significantly greater than those of noncleft side (P < .01). A 3 mm labial, all lingual, and apico-distal ABTs decreased on the cleft side (P < .01). A positive correlation was found between lingual ACH and CRR (R = 0.316, P < .05), between the 3 mm (R = 0.417, P < .05) and 6 mm labial (R = 0.448, P < .05) ABT and CRR. A negative correlation was found between the 3 mm and 6 mm labial ABTs and the root length. It can be suggested that the CRR is related to ACH and ABT. The lingual ACH, the 3 mm, and 6 mm labial ABTs tend to increase with the increasing CRR.

GINGIVAL BIOTYPE- AN APPRAISAL IN THE ESTHETIC ZONE

The interface between the restoration and the gingival tissue seems to have a great influence on the final outcome of various treatments. Therefore, the aim of this study was to evaluate the correlation between different morphometric parameters with the thickness of buccal gingiva at the cemento- enamel junction. In 60 periodontally healthy subjects, the six maxillary anterior teeth were examined. Clinical parameters included the gingival thickness, crown width/crown length ratio (CW/ CL), gingival width (GW), papillary height and transparency of the periodontal probe through the gingival sulcus (TRAN). A positive correlation was found between the gingival thickness (GT) and the crown width/ crown length (CW/CL) ratio as well as the papillary height (PH). A weak negative correlation was found between the transparency of probe TRAN and gingival width (GW) with the gingival thickness (GT). Thus, crown form (CW/CL) and papillary height are helpful indicators to determine the gingival thickness at the cemento- enamel junction. The transparency of probe method is subjective and cannot be relied upon for clinical application.