Biomedical subjects

Tiziano Baccetti

Publications and source records attributed to Tiziano Baccetti.

At least 19 recordsLinked to original sources

PubMed2006

A long-term evaluation of the mandibular Schwarz appliance and the acrylic splint expander in early mixed dentition patients.

INTRODUCTION: The aim of this prospective longitudinal clinical study was to evaluate the short-term and long-term changes in dental-arch dimensions in patients treated with either an acrylic splint rapid maxillary expander alone (RME-only) or a rapid maxillary expander combined with a mandibular removable Schwarz plate (RME-Sz) in the early mixed dentition, followed later by fixed appliances in the permanent dentition. METHODS: The dental casts of 27 RME-only patients were compared with those of 23 RME-Sz patients and 16 untreated controls (CTRL) with constricted maxillary arches at 4 times: pretreatment (T1), after expansion but before fixed appliance therapy (T2), after fixed appliance therapy (T3), and at long-term observation (T4). The mean ages for the treated groups were approximately 9 years at T1, 12 years at T2, 14 years at T3, and 20 years at T4. Arch width, arch depth, arch perimeter, and molar angulation were assessed in all subjects at all observation times. T1-T2, T2-T3, T3-T4, and T1-T4 changes were compared statistically in the treated groups with respect to the CTRL. RESULTS: Treatment with an RME-only or an RME-Sz followed by fixed appliances produced significant short-term and long-term increases in maxillary arch widths compared with the CTRL. The RME-Sz led to significantly more favorable results than the RME-only protocol: (1) significantly greater increases in the transverse width of the mandibular arch and mandibular arch perimeter in the long term, and (2) uprighting of the mandibular posterior teeth buccally, thus allowing for an amount of maxillary expansion that was clinically effective for the correction of moderate tooth size-arch size discrepancies. In the overall observation interval, the significant increases in maxillary and mandibular arch perimeters in the RME-Sz group were 3.8 and 3.7 mm, respectively, when compared with the CTRL. The RME-only protocol produced modest long-term increases in maxillary arch perimeter (2.6 mm); the average long-term increase in mandibular arch perimeter (2.0 mm) in the RME-only group was not statistically significant. CONCLUSIONS: The RME-Sz led to significantly more favorable results than the RME-only protocol.

Analysis of Variance↗

PubMed2006

A prospective long-term study on the effects of rapid maxillary expansion in the early mixed dentition.

INTRODUCTION: The aim of this prospective longitudinal clinical study was to evaluate the short-term and long-term changes in dental-arch dimensions in patients treated with the acrylic splint rapid maxillary expander in the early mixed dentition followed by fixed appliances in the permanent dentition. METHODS: The dental casts of 51 consecutively treated patients (TG) were compared with those of 26 untreated controls (CG) at 3 different times: pretreatment (T1), after expansion and fixed appliance therapy (T2), and at long-term observation (T3). The mean ages for the TG were 8 years 10 months at T1, 13 years 10 months at T2, and 19 years 9 months at T3. Arch widths, arch depth, arch perimeter, and molar angulation were assessed in all subjects at all observation times. T1-T2, T2-T3, and T1-T3 changes were compared statistically in the TG with respect to the corresponding CG. RESULTS: Treatment with an acrylic splint RME followed by fixed appliances produced significantly favorable short-term and long-term changes in almost all maxillary and mandibular arch measurements. The amount of change in both maxillary and mandibular intermolar and intercanine widths fully corrected the initial discrepancies. Approximately 4 mm of long-term relative increase in maxillary arch perimeter, and 2.5 mm additional maintenance of mandibular arch perimeter were observed in the TG compared with the CG. CONCLUSIONS: These results suggest that this protocol is effective and stable for the treatment of constricted maxillary arches, and can relieve modest deficiencies in arch perimeter.

Child↗

PubMed2006

Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review.

The aim of this systematic review of the literature was to assess the scientific evidence on the efficiency of functional appliances in enhancing mandibular growth in Class II subjects. A literature survey was performed by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to January 2005 and used the medical subject headings (MeSH). The following study types that reported data on treatment effects were included: randomized clinical trials (RCTs), and prospective and retrospective longitudinal controlled clinical trials (CCTs) with untreated Class II controls. The search strategy resulted in 704 articles. After selection according to the inclusion/exclusion criteria, 22 articles qualified for the final analysis. Four RCTs and 18 CCTs were retrieved. The quality standards of these investigations ranged from low (3 studies) to medium/high (6 studies). Two-thirds of the samples in the 22 studies reported a clinically significant supplementary elongation in total mandibular length (a change greater than 2.0 mm in the treated group compared with the untreated group) as a result of overall active treatment with functional appliances. The amount of supplementary mandibular growth appears to be significantly larger if the functional treatment is performed at the pubertal peak in skeletal maturation. None of the 4 RCTs reported a clinically significant change in mandibular length induced by functional appliances; 3 of the 4 RCTs treated subjects at a prepubertal stage of skeletal maturity. The Herbst appliance showed the highest coefficient of efficiency (0.28 mm per month) followed by the Twin-block (0.23 mm per month).

Humans↗

PubMed2006

Forces released during alignment with a preadjusted appliance with different types of elastomeric ligatures.

INTRODUCTION: The purpose of this in-vitro study was to compare the forces generated by new nonconventional elastomeric ligatures (NCEL) and conventional elastomeric ligatures (CEL) during leveling and aligning phases. METHODS: The testing model consisted of 5 stainless steel 0.022-in preadjusted brackets for second premolar, first premolar, canine, lateral incisor, and central incisor. The canine bracket was welded to a sliding bar that allowed for different vertical positions. The forces generated by 3 sizes of wires (0.012-, 0.014-, and 0.016-in superelastic nickel-titanium) with the 2 types of elastomeric ligatures at different amounts of upward canine misalignment (1.5, 3, 4.5, and 6 mm) were recorded. RESULTS AND CONCLUSIONS: Significant differences between CEL and NCEL were found for all tested variables (P <.01) with the exception of the 0.014- and 0.016-in wires at canine misalignment of 1.5 mm. A noticeable amount of force was generated with the NCEL at all 4 canine positions with all 3 wire sizes (from about 50 to about 150 g). With 4.5 mm of canine misalignment or more, the average amount of released force with the CEL was approximately zero.

Dental Alloys↗

PubMed2006

Maxillary arch changes during leveling and aligning with fixed appliances and low-friction ligatures.

INTRODUCTION: The aim of this study was to evaluate the changes in the transverse dimension and the perimeter of the maxillary arch produced by a low-friction system during the leveling and aligning phases of fixed appliance therapy. METHODS: The low-friction protocol consisted of a combination of preadjusted brackets, superelastic nickel-titanium archwires, and nonconventional elastomeric ligatures; it was used in 20 consecutively treated patients with mild crowding. RESULTS: Statistically significant increases were recorded for all dentoalveolar widths (with the exception of intermolar width measured lingually) and arch perimeter (3.5 mm on average). The increase in arch perimeter showed a significant negative relationship with the individual perimeter of the maxillary arch before treatment. No significant change was found for arch depth. CONCLUSIONS: The low-friction system produced statistically significant increases in the transverse dentoalveolar width and the perimeter of the maxillary arch during the leveling and aligning phases of treatment with an average duration of 6 months.

Adolescent↗

PubMed2006

Treatment effects of a modified quad-helix in patients with dentoskeletal open bites.

INTRODUCTION: The aim of this study was to investigate the effectiveness of a quad-helix/crib (Q-H/C) appliance in a group of growing subjects with thumb-sucking habits and both dental and skeletal open bites. METHODS: The records of 23 subjects treated with Q-H/C appliances were compared with a control group of 23 untreated subjects with similar vertical relationships. Lateral cephalograms were analyzed before treatment (T1; mean age, 8.4 +/- 1.4 years) and immediately after treatment (T2; mean age, 9.9 +/- 1.5 years). Mean duration of treatment was 1.5 +/- 7 months. The T2-T1 changes in the 2 groups were compared with a nonparametric test for independent samples (Mann-Whitney U test). RESULTS: The average increase in overbite during Q-H/C therapy (3.6 mm more than the control group) overcorrected the amount of anterior open bite at T2. However, 4 of 23 subjects did not show positive overbites at T2. Both the maxillary and mandibular incisors had significantly greater lingual inclinations (about 4.0 degrees) associated with greater extrusion (1.4 and 1.0 mm, respectively) in the Q-H/C group than in the control group. In addition, the treated group showed a greater downward rotation (1.2 degrees) of the palatal plane than did the control group. This change was associated with a greater increase in upper anterior facial height (0.7 mm) and a clinically significant reduction in the palatal plane-mandibular plane angle (-1.7 degrees) in the Q-H/C group with respect to the controls. The upper and lower lips showed significant tendencies toward retraction relative to the E-plane in the treated group (2.6 and 2.9 mm, respectively) compared with the controls. CONCLUSIONS: The Q-H/C appliance was effective in correcting the dental open bite in 90% of growing subjects with thumb-sucking habits and dentoskeletal open bites. The Q-H/C protocol produced a clinically significant improvement in the vertical skeletal relationships because of downward rotation of the palatal plane.

Cephalometry↗

PubMed2006

Friction produced by types of elastomeric ligatures in treatment mechanics with the preadjusted appliance.

The objective was to compare the frictional forces generated by new nonconventional passive elastomeric ligatures (NCL) and conventional elastomeric ligatures (CL) under dry conditions. An experimental model reproducing the right buccal segment of the upper arch and consisting of five stainless steel 0.022-inch preadjusted brackets (from the second premolar through the central incisor) was used to assess both static and kinetic frictional forces produced by NCL and CL. The frictional forces generated by the 0.019 x 0.025-inch stainless steel wire with the two types of elastomeric ligatures were recorded by sliding the wire into the aligned brackets. The friction produced by the 0.014-inch superelastic nickel titanium wire was evaluated both in the presence of aligned brackets and of three-mm misaligned canine bracket. The amount of both static and kinetic frictions were minimal (<10 g) in the NCL group in the presence of aligned brackets with both types of wires, whereas it ranged from a minimum of 95.6 g for the 0.014-inch superelastic nickel titanium wire to a maximum of 590.7 g for the 0.019 x 0.025-inch stainless steel wire when using CL. The amount of both static and kinetic frictions in the presence of a misaligned canine bracket in the NCL group were less than half of that shown by the CL group. A recently developed passive ligature system is able to produce significantly lower levels of frictional forces in vitro when compared with conventional elastomeric modules.

Elastomers↗

PubMed2006

An estimate of craniofacial growth in Class III malocclusion.

OBJECTIVE: To provide an estimate of growth in Class III malocclusion by means of the analysis of a large population of males and females. MATERIALS AND METHODS: The examined sample consisted of pretreatment lateral cephalometric records of 949 (492 females and 457 males) untreated Class III patients of Caucasian ancestry. Cephalometric dentoskeletal measurements at subsequent age periods in Class III subjects were compared with the population values from subjects included in the University of Michigan Growth Study (UMGS) at 11 consecutive age periods (from 6 through 16 years of age), in male and female groups separately. RESULTS: No difference was found between the Class III and normal groups for the sagittal position of the maxilla at any of the age intervals examined. Sagittal mandibular position and dimensions in Class III subjects were consistently larger than in normal subjects, with the interval of largest "increase" in mandibular length occurring on average 1 year later in both female and male Class III subject with respect to subjects with normal occlusion. CONCLUSIONS: Increases in mandibular length were substantially larger in Class III subjects than in subjects with normal occlusion even during the more mature age interval (15 to 16 years). Lower anterior facial height was significantly larger in Class III individuals during the late developmental stages.

Adolescent↗

PubMed2006

Prediction of individual mandibular changes induced by functional jaw orthopedics followed by fixed appliances in Class II patients.

OBJECTIVE: To identify pretreatment cephalometric variables for the prediction of individual mandibular outcomes of functional jaw orthopedics (FJO) followed by fixed appliances in Class II patients treated at the peak in mandibular growth. MATERIALS AND METHODS: The study was performed on 51 subjects (24 females, 27 males) with Class II malocclusion. First-phase therapy was accomplished with a twin block in 16 subjects, a stainless steel crown Herbst in 15 subjects, and an acrylic splint Herbst in 20 subjects. Lateral cephalograms were available at the start of treatment with FJO and at the completion of fixed appliance therapy. All subjects received FJO at the peak in mandibular growth (CS 3 at T1). Individual responsiveness to Class II treatment including FJO was defined on the basis of the T2-T1 increment in total mandibular length (Co-Gn) when compared with untreated Class II subjects. RESULTS: Discriminant analysis identified a single predictive parameter (Co-Go-Me degrees) with a classification power of 80%. Pretreatment vertical and sagittal parameters were not able to improve the prediction based upon the mandibular angle. CONCLUSIONS: A Class II patient at the peak in skeletal maturation (CS 3) with a pretreatment Co-Go-Me degrees smaller than 125.5 degrees is expected to respond favorably to treatment including FJO. A Class II patient at CS 3 with a pretreatment value for Co-Go-Me degrees greater than 125.5 degrees is expected to respond poorly to treatment including FJO.

Adolescent↗

PubMed2006

The diagnostic performance of chronologic age in the assessment of skeletal maturity.

OBJECTIVE: The aim of this study was to analyze the relationship between chronologic age the and individual skeletal maturity as assessed by means of the cervical vertebral maturation (CVM) method during the circumpubertal period. MATERIALS AND METHODS: The evaluated sample of 600 subjects consisted of 100 subjects (50 males and 50 females) for each of 6 age groups, from 9 years through 14 years of age. Individual skeletal maturity for all subjects was determined by using the CVM method. The relationship between chronologic age and the most prevalent CVM stage at each age group was evaluated statistically by means of indicators of diagnostic test performance that specify the ability of a diagnostic test to identify a condition. RESULTS: The diagnostic performance of chronologic age for the detection of the onset of the adolescent peak in skeletal maturation was very low both in males and in females. In male subjects, the chronologic age of 9 years +/- 6 months presented with strong diagnostic power for the identification of a pre-pubertal stage in skeletal maturation. In female subjects, the chronologic age of 14 years +/- 6 months corresponded with a strong probability of a postpubertal stage in skeletal maturation. CONCLUSIONS: In males, chronologic age can identify a pre-pubertal stage of skeletal development, and in females a post-pubertal stage. In both males and females, chronologic age cannot recognize the onset of the adolescent peak in skeletal maturation.

Adolescent↗

PubMed2005

Thin-plate spline analysis of arch form in a Southern European population with an ideal natural occlusion.

The purpose of the present study was to identify the mean configuration of the clinical arch form in a sample of Southern European subjects with ideal natural occlusion by means of Procrustes analysis, and to compare the identified configuration with 10 commercially produced arch forms by means of thin-plate spline (TPS) analysis. The sample comprised the study casts of 50 subjects (26 males and 24 females). The mean age of the sample was 26 years +/- 4 years. All subjects were young Caucasian adults of Southern European ancestry, and presented with an ideal natural occlusion. The three-dimensional (3D) co-ordinates of all dental points (facial axis points) were digitized using a 3D electromagnetic digitizer. The morphometric technique of TPS analysis with permutation tests was used to compare the configurations of landmarks in the various specimens. No sexual dimorphism was found for either upper or lower arch forms when the shape of the arches was assessed independently from size. The commercially available arch form that showed the least, though statistically significant, shape difference with respect to the average calculated configuration was the Brader arch form.

Adult↗

PubMed2005

Treatment effects of bonded RME and vertical-pull chincup followed by fixed appliance in patients with increased vertical dimension.

INTRODUCTION: The aim of this study was to investigate the effectiveness of vertical-pull chincup (VPCC) therapy during an initial rapid maxillary expansion (RME) phase, followed by a second phase of comprehensive orthodontic therapy in growing subjects with mild-to-severe hyperdivergent facial patterns. METHODS: The records of 29 subjects treated with bonded RME combined with VPCC followed by a fixed-appliance phase with continued use of VPCC were compared with a group of 29 well-matched patients treated with bonded RME only. Lateral cephalograms were analyzed before the start of treatment (T1), before the second phase of treatment (T2), and after the second phase of treatment (T3). Mean age at T1 was approximately 9 years for both groups. Total treatment period (phase 1, interim phase, and phase 2) was 5.7 years for the VPCC group and 6.2 years for the bonded RME-only group. Statistical comparison between the 2 groups was performed by means of independent sample t tests on the T2-T1, T3-T2, and T3-T1 changes. Cervical vertebral maturation stages were assessed at T1, T2, and T3. RESULTS: The VPCC induced significantly smaller increases in mandibular plane angle of about 2 degrees , lower anterior facial height of about 2.5 mm, and total anterior facial height of about 3.5 mm, compared with the RME-only subjects. These outcomes reflect the therapeutic changes that occurred during phase 1 treatment; phase 2 treatment was not associated with any significant difference in treatment response. No statistically significant differences in vertical dentoalveolar changes were concurrent with the vertical skeletal changes in the subjects treated with the VPCC compared with the RME-only group. CONCLUSIONS: The clinical significance of VPCC wear over 2 phases of treatment (5.7 years) appears to be limited. The VPCC was most effective during the initial (RME) phase of treatment and of little benefit during the fixed appliance phase.

Cephalometry↗

PubMed2005

Sucking habits and facial hyperdivergency as risk factors for anterior open bite in the mixed dentition.

INTRODUCTION: The aim of this study was to evaluate sucking habits and hyperdivergency as risk factors for anterior open bite in mixed-dentition subjects. METHODS: Anamnestic and pretreatment cephalometric records of 1710 mixed-dentition subjects were assessed for sucking habits, dental open bite, and facial hyperdivergency. RESULTS: The rate of anterior open bite was 17.7%. Multiple logistic regression showed that both prolonged sucking habits and hyperdivergent vertical relationships significantly increased the probability of an anterior dentoalveolar open bite, with a prevalence rate of 36.3%. This was 4 times the prevalence of sucking habits and facial hyperdivergency in subjects without anterior open bite (9.1%). CONCLUSIONS: Prolonged sucking habits and hyperdivergent facial characteristics are significant risk factors for anterior open bite in the mixed dentition.

Age Factors↗

PubMed2005

A prospective study of the short-term treatment effects of the acrylic-splint rapid maxillary expander combined with the lower Schwarz appliance.

This prospective clinical study evaluated the short-term treatment effects of acrylic-splint rapid maxillary expander in conjunction with lower Schwarz appliance (RME-Sz) therapy to the acrylic-splint rapid maxillary expansion alone (RME-only group). Pretreatment and posttreatment lateral cephalograms were analyzed for 25 RME patients and 19 RME-Sz patients. The average time between films ranged between nine and 12 months. Statistical comparisons of the treatment changes in the RME-only and RME-Sz groups were performed by means of independent sample t-tests (P < .05). The largest difference between the two groups was in lower anterior facial height (LAFH). The normally occurring increase in LAFH was not observed in the RME-only group during the treatment period, indicating that the acrylic-splint expander had a posterior "bite block effect" on the developing craniofacial complex. LAFH increased by 1.7 mm in the RME-Sz group, a value similar to that observed in untreated individuals. Slight forward displacement of the maxilla was observed when RME was used alone, and the sagittal position of the maxilla remained unchanged in the RME-Sz group. A significant amount of intrusion of the maxillary molars (-0.8 mm) was noted in the RME-only group, whereas the maxillary molars were prevented from erupting in the RME-Sz group. The lower dentition showed a significantly greater amount of extrusion in the RME-Sz group than in the RME-only group. Finally, the Sz appliance prevented the mesial movement of the lower molars during the treatment period.

Acrylic Resins↗

PubMed2005

Early predictive variables for upper canine impaction as derived from posteroanterior cephalograms.

The aim of this study was to identify a model of cephalometric variables for early diagnosis of the displacement of upper permanent canine and early prognosis of upper canine impaction. Postero-anterior (PA) cephalograms of 43 subjects (22 males and 21 females) with different types of malocclusions in the mixed dentition were analyzed at the time of first observation (mean age 8 years and 5 +/- 9 months). All subjects were reevaluated at the mean age of 14.3 years. At this time the sample was divided into 2 groups according to the presence of canine impaction: nonimpacted canine group (31 subjects) and impacted canine group (12 subjects). Stepwise variable selection on the measurements at the time of first observation identified 2 predictive variables on PA cephalograms, ie, the distance between the center of the canine crown and the midsagittal plane (A3cc to Cg Vertical) and the distance between the jugal process and the midsagittal plane (J to Cg Vertical). The closer the canine crowns to the midsagittal plane and the larger the posterior portion of the hemimaxilla, the higher the probability of canine impaction. Discriminant analysis assigned a classification power of 95.3% to the predictive model. On the basis of the equation generated by the multivariate statistical method, impaction of the maxillary canine for each new case at the age of 8 years can be predicted. The importance of PA cephalograms in the diagnosis and prediction of canine eruption disturbances is emphasized.

Cephalometry↗

PubMed2005

Gender differences in Class III malocclusion.

This study evaluated gender differences in the cephalometric records of a large-scale cross-sectional sample of Caucasian subjects with Class III malocclusion at different developmental ages. The purpose also was to provide average age-related and sex-related data for craniofacial measures in untreated Class III subjects that are used as reference in the diagnostic appraisal of the patient with Class III disharmony. The sample examined consisted of 1094 pretreatment lateral cephalometric records (557 female subjects and 537 male subjects) of Caucasian Class III individuals. The age range for female subjects was between three years six months and 57 years seven months. The male subject group ranged from three years three months to 48 years five months. Twelve age groups were identified. Skeletal maturity at different age periods also was determined using the stage of cervical vertebral maturation. Gender differences for all cephalometric variables were analyzed using parametric statistics. The findings of the study indicated that Class III malocclusion is associated with a significant degree of sexual dimorphism in craniofacial parameters, especially from the age of 13 onward. Male subjects with Class III malocclusion present with significantly larger linear dimensions of the maxilla, mandible, and anterior facial heights when compared with female subjects during the circumpubertal and postpubertal periods.

Adolescent↗

PubMed2005

Early orthodontic treatment of skeletal open-bite malocclusion: a systematic review.

The aim of this study was a systematic review of the literature to assess the scientific evidence on the actual outcome of early treatments of open-bite malocclusions. A literature survey was done by applying the Medline database (Entrez PubMed). The survey covered the period from January 1966 to July 2004 and used the MeSH, Medical Subject Headings. The following study types that reported data on the treatment effects included: randomized clinical trials (RCT), prospective and retrospective studies with concurrent untreated as well as normal controls, and clinical trials comparing at least two treatment strategies without any untreated or normal control group involved. The search strategy resulted in 1049 articles. After selection according to the inclusionary/exclusionary criteria, seven articles qualified for the final review analysis. No RCTs of early treatment of anterior open bite have been performed. Two controlled clinical trials of early anterior open bite have been performed, and these two studies indicated the effectiveness of treatment in the mixed dentition with headgears or functional appliances (or both). Most of the studies had serious problems of lack of power because of small sample size, bias and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods. Thus, the quality level of the studies was not sufficient enough to draw any evidence-based conclusions.

Age Factors↗

PubMed2005

Mandibular growth in subjects with infraoccluded deciduous molars: a superimposition study.

The aim of this longitudinal cephalometric study was to analyze the growth characteristics of the mandible in subjects with infraocclusion of the mandibular deciduous molars. A group of 28 subjects with bilateral infraocclusion of mandibular deciduous molars (IG) were enrolled in a prospective longitudinal study on the growth characteristics of the mandible and compared with a control group (CG) of 28 subjects. Lateral cephalograms were collected in both groups at T1 and at T2, after a mean 19-month interval in the IG and after a mean 16-month interval in the CG. All subjects were observed in the early mixed dentition before the pubertal peak and did not receive any orthodontic treatment during the observation interval. Cephalometric analysis at T1 and superimposition of tracings at T1 and T2 were performed, and statistical comparisons between the two groups were carried out by means of independent sample t-tests. Discriminant analysis on the superimposition data identified Co-Gn angle (angle formed by line Co-Gn at T1 and at T2) as the single discriminant variable between IG and CG. There were significant differences between the two groups as to morphological changes of the mandible and direction of condylar growth, thus demonstrating anterior growth rotation of the mandible in subjects with infraocclusion. Because of the high levels of alveolar bone turnover and remodeling in anterior rotating mandibles, this study suggested that skeletal growth characteristics of the mandible may influence the clinical expression of infraocclusion.

Alveolar Process↗