dental arch

The aim of this study was to examine the possibility of the spontaneous eruption of displaced unerupted maxillary canines after the extraction of the deciduous canine and dental arch expansion and to determine the impact of initial canine position on treatment success rate. Materials and METHODS. The study sample included 50 patients (mean age, 13.5 years [SD, 2.2]) with unilaterally displaced unerupted maxillary canines. Deciduous canines were extracted, and the space for displaced canine was created at the beginning of the study. The follow-up period for the spontaneous eruption was 12 months. The initial vertical, horizontal, labio-palatal position and angle of inclination to the midline of the displaced canine were assessed on panoramic radiographs. RESULTS. Only 42% of displaced canines erupted spontaneously within one-year period (52.9% of labially displaced canines and 36.4% of palatally displaced canines). A significant difference of inclination was determined between sponta...

To compare palatal height index, arch width, and arch length characteristics in Iranian patients presenting with palatal and buccal canine impaction with a matched control group. The casecontrol study examined 53 patients with canine impaction. The subjects were divided into two groups determined by buccal or palatal impaction which were compared with 53 control subjects presenting without impaction. Subjects in the experimental groups were matched with individuals in the control group according to age, gender, crowding and type of malocclusion. Palatal height and arch length were measured with a Korkhaus three-dimensional divider. Arch width was determined in the anterior and posterior portions of the maxillary arch with a digital caliper. Data were compared with paired t-tests. The buccal canine impaction group exhibited mean differences in arch length between the case and control groups of 0.8 mm (SD 1.63, p = 0.041). The differences between the case and control groups in intermo...

This study aimed to establish a safety zone for the placement of mini-implants in the buccal surface between the second maxillary premolar (PM2) and first maxillary molar (M1) of Mongoloids. Thirty-two digital orthopantomograms of Mongoloids were selected and the interdental distance between the second premolar and first molar at 2, 5, 8 and 11 mm from the cemento-enamel junction (CEJ) was measured. The distance between the PM2 and M1 root apices and from the apices to the maxillary sinus was also determined. The average width (mm) at 2 mm was 2.58 +/- 0.53; 5 mm was 3.47 +/- 0.61; 8 mm was 4.00 +/- 0.74, 11 mm was 4.36 +/- 0.71 and the distance between the apices was 7.49 +/- 0.79. Only half of the samples were measured at 11 mm, as many of the root apices were superimposed over the maxillary sinus. The measurement (mm) from PM2 root apex to the sinus was -0.18 +/- 1.56, from the mesiobuccal root apex of M1 (MB1) to the sinus was -1.94 +/- 1.70 and from the midpoint between their a...

To evaluate the feasibility of anterior maxillary segmental distraction (AMSD) to correct maxillary hypoplasia and severe dental crowding in cleft lip and palate (CLP) patients, 7 patients (average age 16.4 years) with maxillary hypoplasia, shortened maxillary dental arch length and severe anterior dental crowding secondary to CLP were selected for this study. After anterior maxillary segmental osteotomy, 3 patients were treated using bilateral internal distraction devices, and 4 patients were treated using rigid external distraction devices. Photographs and radiographs were taken to review the improvement in facial profile and occlusion after distraction. An average 10.25 mm anterior maxillary advancement was obtained in all patients after 10-23 days of distraction and 9-16 weeks of consolidation. The sella-nasion-point A (SNA) angle increased from 69.5 degrees to 79.6 degrees. Midface convexity was greatly improved and velopharyngeal competence was preserved. The maxillary dental ...

The African Plio-Pleistocene hominins known as australopiths evolved derived craniodental features frequently interpreted as adaptations for feeding on either hard, or compliant/tough foods. Among australopiths, Paranthropus boisei is the most robust form, exhibiting traits traditionally hypothesized to produce high bite forces efficiently and strengthen the face against feeding stresses. However, recent mechanical analyses imply that P. boisei may not have been an efficient producer of bite force and that robust morphology in primates is not necessarily strong. Here we use an engineering method, finite element analysis, to show that the facial skeleton of P. boisei is structurally strong, exhibits a strain pattern different from that in chimpanzees (Pan troglodytes) and Australopithecus africanus, and efficiently produces high bite force. It has been suggested that P. boisei consumed a diet of compliant/tough foods like grass blades and sedge pith. However, the blunt occlusal topog...

The objective of this study was to investigate distribution of stresses in the human TMJ discs, generated during clenching into various occlusal positions. The work presents a biomechanical finite element model of interaction of mandibular and maxillary dental arches and the TMJ discs of a particular person, based on real geometrical data obtained from spiral computed tomography two-dimensional images. 3D contour coordinates - point clouds were collected from these images and solid model was created. The system under investigation consisted of eight basic parts: two rigid structures representing the mandibular and maxillary dental arches, two mandibular condyles, two mandibular fossae of temporal bone, and solid models of two articular discs. The model of maxillary dental arch was fixed in space. The model of the mandibular dental arch was able to move in space synchronically with the mandibular condyles under action of applied forces, which were considered as prescribed and known a...

Introduction: Since the emergence of normal occlusion concept, selecting an appropriate treatment plan with or without tooth extraction has been a controversial subject. Nowadays, both methods can be successfully used for treatment of patients. However, some clinicians still believe that non-extraction orthodontic treatments have fewer complications. The purpose of this study was to evaluate dental arch dimensional changes following non-extraction orthodontic treatment.
Materials &Methods: A total of 200 pre- and post-treatment diagnostic dental casts belonging to 100 patients (non-ext treated by 0.18 roth system) who met the inclusion criteria for this study were collected from the archives of Shahid Beheshti Dental School. Sampling was nonrandomized. A digital caliper with the accuracy of 0.1 mm was used for the measurement of variables such as inter-canine width , inter-premolar width and inter-molar width.
Results: Non-extraction orthodontic treatment increased all the variables, except for the mandibular inter-canine width and incisor-canine distance.
Conclusion: Non-extraction orthodontic treatment causes a significant increase in almost all dental arch parameters. This increase manifests as teeth flaring.

Infraocclusion of deciduous molars is often associated with ankylosis. Such teeth are believed to be potential sites of malocclusion, with a risk of tipping of neighboring teeth and loss of space. Extraction has therefore been the most widely recommended treatment. The aim of this study was to follow longitudinally the effect of extraction versus nonextraction treatment in twenty-three homologous pairs of mandibular deciduous molars with infraocclusion when unilateral extraction was performed. The study comprised fifteen children with a mean age at the start of 10.1 years. Recordings were made at the start of the study and every 6 months thereafter until eruption of permanent successors. Periodic identical periapical radiographs and study models were taken every 6 months. Ten of the twenty-three mandibular deciduous molars on the nonextraction side showed progression of the degree of infraocclusion. All infraoccluded deciduous molars exfoliated within the normal time. There was a no...

With the advent of digital study models, the importance of being able to evaluate space requirements becomes valuable to treatment planning and the justification for any required extraction pattern. This study was undertaken to compare the validity and reliability of the Royal London space analysis (RLSA) undertaken on plaster as compared with digital models. A pilot study (n = 5) was undertaken on plaster and digital models to evaluate the feasibility of digital space planning. This also helped to determine the sample size calculation and as a result, 30 sets of study models with specified inclusion criteria were selected. All five components of the RLSA, namely: crowding; depth of occlusal curve; arch expansion/contraction; incisor antero-posterior advancement and inclination (assessed from the pre-treatment lateral cephalogram) were accounted for in relation to both model types. The plaster models served as the gold standard. Intra-operator measurement error (reliability) was eva...

Increasing lower dental arch crowding with the age is a recognized clinical problem, and one that has become more apparent in recent years as more adults retain their teeth longer. One of the theories is that the erupting third molars push anterior teeth forward and cause their crowding. On the other hand, a number of studies found no correlation between lower third molars and lower incisor crowding. Because of all these contrasting findings this study was started to re-evaluate correlation between third molars presence and lower dental arch crowding. The study group consisted of 91 subjects with an average age 21.01+/-4.13 years. The individual, quantitative and cast-based analytical registration of crowding was based on the measurements of mesiodistal width of teeth and related to the length of the appropriate segment of the lower dental arch. No statistically significant third molar presence-specific differences were recorded in the lower dental arch crowding between the groups w...

Intra-oral 3D scanning of dentitions has the potential to provide a fast, accurate and non-invasive method of recording dental information. The aim of this study was to assess the reliability of measurements of human dental casts made using a portable intra-oral 3D scanner appropriate for field use. Two examiners each measured 84 tooth and 26 arch features of 50 sets of upper and lower human dental casts using digital hand-held callipers, and secondly using the measuring tool provided with the Zfx IntraScan intraoral 3D scanner applied to the virtual dental casts. The measurements were repeated at least one week later. Reliability and validity were quantified concurrently by calculation of intra-class correlation coefficients (ICC) and standard errors of measurement (SEM). The measurements of the 110 landmark features of human dental casts made using the intra-oral 3D scanner were virtually indistinguishable from measurements of the same features made using conventional hand-held ca...

The aim of the present study was to determine the morphological differences in the base of the skull of individuals with cleft lip and palate and Class III malocclusion in comparison to control groups with Class I and Class III malocclusion. A total of 89 individuals (males and females) aged between 5 and 27 years old (Class I, n = 32; Class III, n = 29; and Class III individuals with unilateral cleft lip and palate, n = 28) attending PUC-MG Dental Center and Cleft Lip/Palate Care Center of Baleia Hospital and PUC-MG (CENTRARE) were selected. Linear and angular measurements of the base of the skull, maxilla and mandible were performed and assessed by a single calibrated examiner by means of cephalometric radiographs. Statistical analysis involved ANCOVA and Bonferroni correction. No significant differences with regard to the base of the skull were found between the control group (Class I) and individuals with cleft lip and palate (P > 0.017). The cleft lip/palate group differed f...

The objective of this study was to evaluate children's respiratory patterns in the mixed dentition, by means of acoustic rhinometry, and its relation to the upper arch width development. Fifty patients were examined, 25 females and 25 males with mean age of eight years and seven months. All of them were submitted to acoustic rhinometry and upper and lower arch impressions to obtain plaster models. The upper arch analysis was accomplished by measuring the interdental transverse distance of the upper teeth, deciduous canines (measurement 1), deciduous first molars (measurement 2), deciduous second molars (measurement 3) and the first molars (measurement 4). The results showed that an increased left nasal cavity area in females means an increased interdental distance of the deciduous first molars and deciduous second molars and an increased interdental distance of the deciduous canines, deciduous first and second molars in males. It was concluded that there is a correlation between...

Stature is a measurable feature of the body, useful in human identification, which may include or exclude an individual from a missing persons list. The aim of this study is to analyze the Carrea´s index for stature estimation in dental arches with normal dentition, crowding and diastema. Plaster casts of 51 students of the Federal University of Paraíba were analyzed. Each hemiarch was divided according to the dental position, and the elements were measured with divider and digital calipers. Considering the normal and crowded dentition, the Carrea´s index presented a satisfactory success percentage, between 72.2% and 95.2%, with no statistically significant difference between sexes or between right and left sides. The presence of diastema reduced the number of matches to less than 62.5%. It was concluded that the Carrea´s index is a reliable method for height estimation in arches with normal and crowded dentitions, useful in males and females, and in the right and left sides. Howeve...

AIM To quantify and localise differences in Class I and Class II dental arches in Malay schoolchildren. METHODS The subjects were 50 Malay schoolchildren (Mean age: 15 + 0.7 years) with either Class I (N = 25) or Class II (N = 25) malocclusions. Fourteen homologous landmarks on the upper and lower study models of the subjects were digitised using MorphoStudio software, and the Procrustes means were computed. The mean Class I and Class II configurations were subjected to ftests and finite element analysis. RESULTS Normalised upper arch Class I and Class II configurations were statistically different (p < 0.05), but the lower arches were not. However, normalised Class II linear parameters were statistically smaller in the upper arch and larger in the lower arch. The upper Class II dental arch was narrower by 15 per cent and asymmetric changes in size (11-20 per cent) were localised in the labial and buccal regions of the lower Class II arch. CONCLUSIONS Size and shape differences b...

The diversity of notation systems for recording dental characteristics and the means used to display them makes comparisons and interdisciplinary collaboration difficult. The aim of the present study is to propose the use of a method employed by experts worldwide but which may be new to bioarchaeologists. Since 1971 we have used the International Dental Federation (FDI) system, which provides the location of dental characteristics and the morphotype of each tooth at the same time, thus avoiding the need to specify upper or lower, and right or left to state the tooth position in the dental arch. To demonstrate the use of the FDI system, we applied it to the study of dental wear in a mediaeval Mediterranean skeletal sample from France consisting of 58 paired mandibles and maxillae belonging to 29 female and 29 male adults and divided into two age groups: young or aged 20-30 years, and mature or aged over 30 years. Tooth wear was recorded according to Brabant's index, which consists of four levels and four directions. Data were displayed in the form of curves, according to the FDI and taking age and sex into account. Analysis of the results shows a tooth wear distribution that is significantly different between upper and lower horizontal and oblique directions in females and males, and between upper and lower horizontal and oblique heavy wear in females and males. Moreover, a significantly asymmetrical horizontal and oblique distribution of wear was found in the young adult group. Thus, the use of criteria defined by precise reference points for recording data, and displaying results in the form of curves, makes comparison using superimposition easy and reliable and permits a more objective study of tooth wear. Furthermore, using a notation system that is employed worldwide helps to build multidisciplinary projects, and offers the possibility of comparing large amounts of data easily, which should provide enhanced data for bioarchaeology in the future.

The purpose of the present study was to assess the correlation between transverse expansion and the increase in upper arch perimeter, after maxillary expansion. Dental casts of eighteen patients were obtained before treatment and again five months after maxillary expansion. Measurements of intermolar width, intercanine width, arch length and arch perimeter were made with a digital caliper on photocopies taken from the dental casts. After assessment of the method error, a multiple regression model was developed following the identification of the best subset of variables. The resulting equation led to the conclusion that the increase in arch perimeter is approximately given by the addition of 0.54 times the intercanine expansion, and 0.87 times the arch length alteration.

This study aimed to establish a safety zone for the placement of mini-implants in the buccal surface between the second maxillary premolar (PM2) and first maxillary molar (M1) of Mongoloids. Thirty-two digital orthopantomograms of Mongoloids were selected and the interdental distance between the second premolar and first molar at 2, 5, 8 and 11 mm from the cemento-enamel junction (CEJ) was measured. The distance between the PM2 and M1 root apices and from the apices to the maxillary sinus was also determined. The average width (mm) at 2 mm was 2.58 +/- 0.53; 5 mm was 3.47 +/- 0.61; 8 mm was 4.00 +/- 0.74, 11 mm was 4.36 +/- 0.71 and the distance between the apices was 7.49 +/- 0.79. Only half of the samples were measured at 11 mm, as many of the root apices were superimposed over the maxillary sinus. The measurement (mm) from PM2 root apex to the sinus was -0.18 +/- 1.56, from the mesiobuccal root apex of M1 (MB1) to the sinus was -1.94 +/- 1.70 and from the midpoint between their a...

Two case reports demonstrate a new orthodontic method that offers short treatment times and the ability to simultaneously reshape and increase the buccolingual thickness of the supporting alveolar bone. A 24-year-old man with a Class I severely crowded malocclusion and an overly constricted maxilla with concomitant posterior crossbites and a 17-year-old female with a Class I moderately to severely crowded malocclusion requested shortened orthodontic treatment times. This new surgery technique included buccal and lingual full-thickness flaps, selective partial decortication of the cortical plates, concomitant bone grafting/augmentation, and primary flap closure. Following the surgery, orthodontic adjustments were made approximately every 2 weeks. From bracketing to debracketing, both cases were completed in approximately 6 months and 2 weeks. Posttreatment evaluation of both patients revealed good results. At approximately 15 months following surgery in one patient, a full-thickness ...

The purpose of the present study was to assess the correlation between transverse expansion and the increase in upper arch perimeter, after maxillary expansion. Dental casts of eighteen patients were obtained before treatment and again five months after maxillary expansion. Measurements of intermolar width, intercanine width, arch length and arch perimeter were made with a digital caliper on photocopies taken from the dental casts. After assessment of the method error, a multiple regression model was developed following the identification of the best subset of variables. The resulting equation led to the conclusion that the increase in arch perimeter is approximately given by the addition of 0.54 times the intercanine expansion, and 0.87 times the arch length alteration.

Objective: To evaluate longitudinally the occlusal changes between the deciduous and early mixed dentition stages in Nigerian children. Materials and Methods: The occlusion of 145 3- to 5-year-old children was initially assessed at a popular pre-primary school center in Ibadan, Nigeria in October 2002, using the Foster and Hamilton criteria. The same group of children was followed up for reexamination in October 2006 in the primary school section of the center. Of 61 students who were located and reexamined, 54 (26 male and 28 female) qualified for the study. The molar relationship was assessed using Angle classification, and other occlusal features such as spacing, crowding, overbite, and overjet were also assessed. Descriptive statistics, chi-square test, as well as Pearson correlation coefficient, were applied as appropriate in the analysis of the data. Results: Of 32 subjects initially having a flush terminal relationship (Class 1), 22 (68.7%) resulted in a Class I molar relatio...

No randomized controlled trial has tried to compare transverse dental arch changes between the lingual and labial orthodontic fixed appliances in the early stage of treatment. To compare upper dental arch changes between lingual and labial fixed orthodontic appliances after leveling and alignment. Parallel-groups randomized controlled trial on patients with class I moderate crowding teeth treated at the University of Al-Baath Dental School in Hamah, Syria. About 102 patients with crowded teeth and class I malocclusion were evaluated and 58 patients fulflled the inclusion criteria. Randomization was performed using computer generated tables; allocation was concealed using sequentially numbered opaque and sealed envelopes. About 52 participants were analyzed (mean age 21.5 ± 3.2 years). They were randomly distributed into two groups with 26 patients in each (1:1 allocation ratio). Lingual vs labial fixed orthodontic appliances were used. Intercanine width, interpremolar width, intermo...

After loss of natural teeth, provision of prosthodontic services almost becomes necessity in the present day living. To provide effective mastication teeth have peculiar forms. To make it more efficient both functionally and biologically, they are arranged in particular geometric manner referred to as dental arch. The objective of this study was to compare the distance between mesial edge of the maxillary central incisors and posterior border of the incisive papilla in dentate individuals with different arch forms. After sample selection, impressions were made for upper and lower arches and the resultant casts were standardised. Arch forms were assessed by their morphological description. Measurements on cast were recorded for incisive papilla (IP) and maxillary central incisor (CI) distance after securing it on cast surveyor. Ovoid arch form was the most frequently observed arch form both in males (57%) and females (68%) while their combination (Ovoid Square and Ovoid tapered) were...

This study compares the accuracy of space prediction for the unerupted permanent canines and premolars by a recognized method of mixed dentition space analysis (Moyers technique) vs estimation by simple visual observation (SVO). Twenty clinicians with varying levels of dental experience and training blindly assessed study models of 4 intact arches (2 maxillary and 2 mandibular) from 3 patients in the mixed dentition using both Moyers and SVO space prediction methods. Corresponding full-mouth panoramic radiographs were available for each case. Follow-up records of the eventual outcome in the permanent dentition for each case available (ie, study models prior to any form of orthodontic intervention) served as the standard for further comparison of the space predictions made. Predictions by both methods were compared with each other as well as with the eventual space situation in the permanent dentition. The differences in overall mean space prediction between the Moyers technique (excluding molar shift) and SVO ranged between 3.67 mm to 6.9 mm (lower arches) and 4.3 mm to 4.8 mm (upper arches). Diagnostic consistency between both methods' predictions was highly variable, with correlation ranging from moderate (r = 0.53, P = .01) to very weak (r = -0.1). Generally, more crowding was estimated with the SVO method's predictions. However, the inclusion of molar shift in the Moyers analysis resulted in the prediction of more crowding in the mandible compared to SVO and eventual outcome in the permanent dentition. The range and variability in predictions were always smaller with the Moyers technique compared to SVO. Neither technique's mean space prediction more closely resembled the eventual space situation in the permanent dentition. This study demonstrated that although the Moyers technique demonstrated less variation and more reproducibility than SVO in its space predictions, neither of the techniques was any more accurate in predicting the final space outcome in the permanent dentition.

Objective The natural accumulation of supragingival plaque on surfaces of human teeth is associated with gingival inflammation and the initiation of common oral diseases. This study evaluated the distribution of dental plaque and gingivitis scores within the dental arches after prophylaxis. Methods Adult subjects from the Dharwad, India area representing the general population who provided written informed consent were scheduled for screening. Healthy subjects over the age of 18 years, not currently requiring any medical or dental care, and presenting with a complement of at least 20 natural teeth were recruited for this parallel design study. Enrolled subjects (n = 41) underwent oral examinations for dental plaque (PI) and gingivitis (GI) using the Turesky modification of the Quigley-Hein and the Löe-Silness Index, respectively, at the baseline visit, followed by a whole mouth dental prophylaxis. Subjects were given fluoride toothpaste for twice daily oral hygiene for the next 30 d...

Objective: To reassess the inclination of lower incisors and evaluate possible associations with gender, age, symphyseal parameters, and skeletal pattern. Materials and Methods: Twelve hundred and seventy-two (605 females, 667 males) cephalograms of untreated subjects of a craniofacial growth study (age: 8–16 years) were evaluated. Correlations between the angulation of the lower incisors and age, symphyseal distances (height, width, and depth), symphyseal ratios (height-width, height-depth), and skeletal angles (divergence of the jaws and gonial angle) were investigated for all ages separately and for both sexes independently. Results: The inclination of lower incisors increased over age (8 years: girls  =  93.9° [95% CI, 92.3°–95.7°], boys  =  93.3° [95% CI, 91.8°–94.9°]; 16 years: girls  =  96.1° [95% CI, 94.1°–98.2°], boys  =  97.1° [95% CI, 95.6°–98.6°]). Inclination of lower incisors correlated with the divergence of the jaws for all ages significantly or highly significantly,...