Giuseppe Siciliani

Quantitative cone-beam computed tomography evaluation of palatal bone thickness for orthodontic miniscrew placement

INTRODUCTION The purpose of this study was to evaluate the 3-dimensional thickness of the palate to determine the best location to place miniscrews. METHODS We selected digital volumetric tomographs from 162 healthy subjects, aged 10 to 44 years (80 male, 82 female). The sample was divided into 3 groups. Group A included 52 subjects (ages, 10-15 years; 28 boys, 24 girls); group B included 38 subjects (ages, 15-20 years; 18 males, 20 females), and group C had 72 subjects (age, 20-44 years; 34 men, 38 women). Ninety-degree paracoronal views of the palatal region at 4, 8, 16, and 24 mm posterior to the incisive foramen were reconstructed, and bone height was measured laterally from the midline in each reconstruction at 0-, 3-, and 6-mm increments to describe the topography of the palate. Measurements of palatal height in 27 of the 162 patients were made by 2 different investigators. Method error was calculated according to the Dahlberg formula (S(2) = Sigmad(2)/2n), and systematic error was evaluated with the dependent Student t test, with P <0.05 considered significant. RESULTS The thickest bone (4-8 mm) was found in the anterior part of the palate, at the suture and in the paramedian areas, but the posterior region, despite its reduced thickness, is also suitable for miniscrews. The Kruskal-Wallis test showed no significant differences between the groups in the various palatal sections (median suture, 3 and 6 mm to the right and left of the suture) except between groups A and C in the 16-mm paracoronal section at 6 mm to the right and left of the suture. There were no statistically significant differences due to sex or between the right and left sides of the palate. CONCLUSIONS The anterior region is the thickest part of the palate, but the bone thickness in the posterior region is also suitable for screws of appropriate diameter and length.

Decoy oligodeoxynucleotides targeting NF-kappaB transcription factors: induction of apoptosis in human primary osteoclasts

Proteins belonging to the nuclear factor kappaB (NF-kappaB) superfamily are involved in osteoclast formation, playing a very important role for both differentiation of osteoclast precursors and survival of mature osteoclasts. Several drugs used to fight bone loss in a variety of human pathologies, including osteoporosis, act by increasing the frequency of osteoclast apoptosis, since it was demonstrated that small changes in osteoclast apoptosis can result in large changes in bone formation. In this respect, targeting of NF-kappaB transcription factor could be of great interest. Among nonviral gene therapy strategies recently proposed to inhibit or even block NF-kappaB activity, the transcription factor decoy (TFD) should be taken in great consideration. The main issue of the present study was to examine the effects of decoy DNA/DNA molecules targeting NF-kappaB on apoptosis of human osteoclasts (OCs), with the aim to interfere with the pathway regulating osteoclast differentiation and programmed cell death. To this aim, we used a mixture of receptor activator of NF-kappaB ligand (RANKL), macrophage colony-stimulating factor (M-CSF) and parathyroid hormone (PTH) to prepare human OCs from peripheral blood cells. Then, transfection with the decoy molecules targeting NF-kappaB was performed. The results obtained demonstrate that in primary cells expressing typical osteoclast markers such as TRAP and MMP9, NF-kappaB decoy significantly stimulated apoptosis. Inhibition of IL-6 expression and induction of Caspase 3 were found in OCs treated with NF-kappaB DNA/DNA decoys. We consider these data as the basis for setting up experimental conditions allowing nonviral gene therapy of several bone disorders.

Load deflection characteristics and force level of nickel titanium initial archwires

OBJECTIVES To investigate and compare the characteristics of commonly used types of traditional and heat-activated initial archwire by plotting their load/deflection graphs and quantifying three suitable parameters describing the discharge plateau phase. MATERIALS AND METHODS Forty-eight archwires (22 nickel titanium [NiTi] and 26 heat-activated) of cross-sectional diameter ranging from 0.010 to 0.016 inch were obtained from seven different manufacturers. A modified three-point wire-bending test was performed on three analogous samples of each type of archwire at a constant temperature (37.0°C). For each resulting load/deflection curve, the plateau section was isolated, along with the mean value of the average plateau force, the plateau length, and the plateau slope for each type of wire obtained. RESULTS Statistically significant differences were found between almost all wires for the three parameters considered. Statistically significant differences were also found between traditional and heat-activated archwires, the latter of which generated longer plateaus and lighter average forces. The increase in average force seen with increasing diameter tended to be rather stable, although some differences were noted between traditional and heat-activated wires. CONCLUSIONS Although great variation was seen in the plateau behavior, heat-activated versions appear to generate lighter forces over greater deflection plateaus. On average, the increase in plateau force was roughly 50% when the diameter was increased by 0.002 inch (from 0.012 to 0.014 and from 0.014 to 0.016 inch) and about 150% when the diameter was increased by 0.004 inch (from 0.012 to 0.016), with differences between traditional and heat-activated wires noted in this case.

Computed tomography evaluation of mandibular incisor bony support in untreated patients

INTRODUCTION In this study, we aimed to verify, via computed volumetric tomography, a correlation between the morphology of the mandibular symphysis and the various facial types. METHODS From a sample of 148 digital volumetric tomographs, the subjects were classified as either short face (25 subjects), normal face (27 subjects), or long face (28 subjects) according to the average values of their Frankfort-mandibular plane angle. The 80 healthy subjects were between 12 and 40 years of age. Tomography was carried out using NewTom 3G volume scanner (QRsr1, Verona, Italy). The following parameters were measured on the sections corresponding to the 4 mandibular incisors: height, thickness, and area of the entire symphysis; height, thickness, and area of the cancellous bone of the symphysis; distance of the vestibular and lingual cortices from the apices of the 4 incisors; and possible inclination of each mandibular incisor, expressed in degrees. The F test or analysis of variance (ANOVA) and the Tukey HSD Test were subsequently used. RESULTS The total thickness of the symphysis was greater in the short-face subjects than in the long-face subjects. No statistically significant differences in the total and cancellous areas of the symphysis were found between the 3 facial types. In all 3 groups, the total and cancellous heights and areas were greater at the central incisors than at the lateral incisors. CONCLUSIONS There is a statistically significant relationship between facial type and the total thickness of the mandibular symphysis.

Comparison of different orthodontic devices for mandibular symphyseal distraction osteogenesis: A finite element study

INTRODUCTION In this study, we aimed to analyze the displacement field and the level of stability for a human mandible that had symphyseal distraction osteogenesis. The mandible was fitted with various orthodontic devices: tooth borne, bone borne, and hybrid. Three-dimensional nonlinear finite element analyses were performed to study differences between the nominal aperture of the device and the actual mandibular distraction. Furthermore, displacement fields of the mandibular arch evaluated with and without mastication forces were compared to determine the level of stability of each appliance. METHODS Computed tomography scan images of the mandible were processed to create the finite element model, which was completed by modeling the distraction device. Three cases were considered: the distraction device attached to the first molar and the first premolar (tooth borne), to the canine and basal bones (hybrid), or only to the basal bone (bone borne). The nominal aperture of each device was 2 mm. Mandibular displacements in the mastication phase were analyzed in the case of unilateral occlusion on the second premolar. RESULTS AND CONCLUSIONS Tooth-borne and hybrid devices allow orthodontists to better control the effective displacement transferred to the mandible by the distractor. Displacements of the mandibular arch were closer to the nominal aperture of the distractor than in the case of the bone-borne device. Hybrid devices were more stable under functional loads. However, parasitic rotations of the mandibular arms caused by mastication might counteract the benefits of distraction.

Upper Incisor Position and Bony Support in Untreated Patients as Seen on CBCT

OBJECTIVE To test the null hypothesis that there are no correlations between the morphology of the upper jaw, the position of the upper incisors, and facial type. MATERIALS AND METHODS From a sample of 191 patients, the FMA angle was used to select 20 short face type, 20 norm face type, and 20 long face type patients, aged 12 to 40 years. Using cone-beam computed tomography (CBCT), tomography was carried out on sagittal sections corresponding to the four upper incisors. Some parameters defining the dentoskeletal relationships, the alveolar thickness, the alveolar height, and the dental movement were measured. The measurements were processed using analysis of variance and Tukeys test. RESULTS At the upper central incisors, short face type patients presented a greater alveolar bone thickness than long face type patients. In short face type and norm face type subjects the root apex of the upper incisors was farther away from the lingual cortex than in the long face type patients. At the central incisors the alveolar thickness was greater and the lingual cortex was higher with respect to the lateral incisors in all three facial types. CONCLUSION At the upper incisors, facial type is statistically significantly correlated with both alveolar bone thickness and distance between the root apex and lingual cortex.

Long-term stability of alveolar bone grafts in cleft palate patients

INTRODUCTION Many authors have examined the surgical bone treatment of cleft palate patients, but no study has emphasized the role of orthodontic therapy. The aims of this study were to evaluate the long-term stability of bone grafts when using an orthodontic-surgical protocol, to determine the success of bone grafts in minor vs severe clefts, and to develop a qualitative method for assessing the success of bone grafting. METHODS Forty-nine patients were included in this study. Occlusal x-rays were taken before (T0), immediately after (T1), and at least 1 year after bone grafting (T2). Two radiographic parameters were analyzed adjacent to the cleft side: the vertical bone level (Bergland scale) and the horizontal bone level (Witherow-derived scale). RESULTS The bone graft success at T2 was 91.84% (95% confidence interval, 84.55-96.41). The severity of the cleft before grafting was not statistically correlated with success at T2 (P <0.05). The concordance rate between Bergland and Witherow values was 87.07% (95% confidence interval, 82.69-90.69). The variables analyzed (sex, age, type of cleft, lateral incisor agenesis) were not statistically correlated (P <0.05) with the stability of bone graft. Based on the results, the only factor involved in the stability of the graft seems to be dental age at the time of bone grafting and the orthodontic therapy before and after grafting. CONCLUSIONS It seems appropriate to recommend early application of a surgical-orthodontic protocol to treat cleft lip and palate patients, prevent postoperative bone resorption, and guarantee correct positioning of the teeth.

Changes in the oral environment after placement of lingual and labial orthodontic appliances

BackgroundThis study compared the oral hygiene and caries risk of patients treated with labial and lingual orthodontic appliances throughout a prospective evaluation of the status of the oral environment before and after bracket placement.MethodsA total of 20 orthodontic patients aged 19 to 23 years were included in the study and were divided into two groups: 10 patients wore Roth labial appliance (American Orthodontics, Sheboygan, WI, USA) and 10 patients wore STb lingual appliance (Ormco Corporation, Glendora, CA, USA). Plaque index (PI), gingival bleeding index (GBI), salivary flow rate, saliva buffer capacity, salivary pH, and Streptococcus mutans and Lactobacillus counts in saliva were determined at three time points: before orthodontic appliance placement (T 0), 4 weeks after bonding (T 1), and 8 weeks after bonding (T 2). After appliance placement, all patients were periodically educated to the oral hygiene procedures. Wilcoxon rank and Mann-Whitney U tests were used to determine intragroup and intergroup differences as regards qualitative data. To compare quantitative data between the groups, chi-square and Fishers exact tests were undertaken, while intragroup differences were tested with McNemar test. The level of statistical significance was set at p < 0.05.ResultsStatistical analysis of the data obtained revealed a statistically significant difference between the data of T 0 and T 1 and the data of T 0 and T 2 of the PI scores and between T 0 and T 2 of the GBI scores in the group treated with the lingual appliance. The GBI value increased significantly between T 0 and T 1 but decreased significantly between T 1 and T 2 (p < 0.01) in the group treated with labial appliance. S. mutans counts increased significantly between T 0 and T 2 in the saliva samples of patients treated with lingual appliance. No statistically significant differences were found between S. mutans and Lactobacillus counts at the three terms of saliva collection in patients treated with labial appliance. No statistically significant differences were found between the two groups at the three time points as regards the salivary flow rate and saliva buffer capacity.ConclusionsLingual and labial orthodontic appliances showed a different potential in modifying the investigated clinical parameters: patients wearing STb lingual orthodontic appliance had more plaque retention 4 and 8 weeks after bonding, while there were more gingival inflammation and more S. mutans counts 8 weeks after bonding. No differences were found between the two groups as regards the Lactobacillus counts, the salivary flow rate, and saliva buffer capacity.

Arch width changes with a rapid maxillary expansion appliance anchored to the primary teeth.

OBJECTIVE To examine the dimensional changes after rapid maxillary expansion (RME) carried out in the transitional dentition with the primary teeth as anchorage. MATERIALS AND METHODS Group A was composed of 31 consecutive transitional dentition patients with posterior quadrant crossbites treated with a Haas-type RME appliance anchored on the maxillary primary molars and canines. No treatment was administered after palatal expansion. Study models were made before RME (T1), at appliance removal (T2), and at least 1 year after appliance removal (T3). A control sample of 60 individuals with posterior quadrant crossbites who had had no orthodontic treatment was categorized into group B (30 individuals with an average age comparable with the treated patients at T2) and group C (30 individuals with an average age comparable with the treated patients at T3). RESULTS Permanent molar crossbites were corrected at T2, and this correction was maintained at T3 in all patients. The mean permanent maxillary intermolar width was 42.6 +/- 2.3 mm at T1, 46.7 +/- 1.9 mm at T2 (P < .01), and 46.3 +/- 1.8 mm at T3 (P < .01) in group A; 42.9 +/- 2.7 mm (P < .01) in group B; and 44.4 +/- 3.0 (P < .01) in group C. Premolar and canine widths were slightly wider than the control at T3. CONCLUSION To avoid undesirable treatment-induced effects on maxillary permanent molars, a stable transverse correction could be achieved with the RME appliance anchored on the primary teeth.

Dental arch changes following rapid maxillary expansion.

The purpose of this research was to evaluate changes in upper arch dimension and form following rapid maxillary expansion (RME) using a modified Haas appliance in the primary dentition. The sample comprised 49 children [17 males, 32 females, mean age 7 years 5 months, standard deviation (SD) 1 year 1 month] with a crossbite or maxillary crowding. Twenty patients had a normal SN-GoGn angle (7 males, 13 females, mean 33.25 degrees, SD 2.10), three were low angle (1 male, 2 females, mean 27.67 degrees, SD 2.31), and 22 were high angle (8 males, 14 females, mean 39.95 degrees, SD 3.15). The vertical dimensions of four patients could not be measured, due to the unavailability of radiographs. Expansion was undertaken to either correct a crossbite or treat maxillary crowding. The upper dental casts were analysed using a computerized system: before treatment (T1), at appliance removal (T2), and 2 years 4 months after appliance removal (T3). Using bootstrap statistical analysis applied to distance ratio values [Euclidean distance matrix analysis (EDMA)], it was found that 48 patients showed a change in arch form. In 40.82 per cent (n = 20, group A), the arch form changed from T1 to T2, T1 to T3, and T2 to T3. In 32.65 per cent (n = 16, group B), it varied from T1 to T2 but relapsed at T3 to the form of T1. For 24.5 per cent (n = 12, group C), it changed from T1 to T2 but maintained the same form at T3. The favourable characteristics for obtaining expansion, identified by logistic regression analysis, were being male, of an immature stage of dental development (lateral incisor not fully erupted) and the presence of a lateral crossbite. Intercanine and intermolar widths, arch length, and the distance between the interincisive point and the line joining the canines (depth of the intercanine arch) at the different time points were analysed using a two-tailed t-test (P < 0.05). For the whole group, the increase in intercanine and intermolar width and in the depth of the intercanine arch was significant. Comparison between groups A, B, and C was undertaken using an analysis of variance, but there was no significant difference between the groups. This modified type of Haas appliance was able to increase the transverse dimension of the maxillary dental arch in the mixed dentition. The most appropriate timing for treatment appears to be before the eruption of the permanent lateral incisors.