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Autotransplantation is a treatment option with high reported survival rates to replace failing teeth in the anterior maxilla. This treatment requires a multidisciplinary approach from orthodontists, paediatric dentists, restorative dentists, and oral and maxillofacial surgeons to achieve successful outcomes. Success is dependent on many factors including stage of root development, handling of the periodontal ligament, extra-alveolar time and splinting. This case report presents the novel use of digitally designed and three-dimensional (3D) printed surgical templates to aid intraoperatively and reduce the extra-alveolar time. A preoperative cone-beam computed tomography scan allowed digital planning and construction of surgical templates that replicated the exact root dimensions of impacted maxillary canines. These templates were subsequently 3D printed in resin, sterilised and utilised intraoperatively to aid socket preparation before the surgical autotransplantation.

Background. The term ‘amelogenesis imperfecta’ (AI) describes a diverse group of hereditary conditions primarily affecting the quality and/or quantity of dental enamel. Case report. This paper describes a case in which hypoplastic AI with delayed/failure of eruption of the permanent teeth was shown to be associated with renal calcification. Conclusion. Given the importance of the renal involvement, the authors suggest that paediatric dentists consider referring all children with this dental phenotype for renal ultrasound examination.

We describe the removal of a lower second molar tooth in which preoperative cone-beam computed tomography (CBCT) showed that the inferior alveolar nerve (IAN) was encased in the distal apex of the root of the tooth. During operation the nerve was found to be entirely separate from the apex of the root and not involved. With the wider use of CBCT in the treatment planning of dentoalveolar surgery, this case represents a cautionary tale to the clinician on reliance on clinical imaging and software in guiding the decision making process.

The management of patients with congenitally missing teeth can be a challenge and, in many cases, requires multidisciplinary care. In this four-part series, a contemporary approach to managing this group of patients is discussed. This first paper examines the terminology, epidemiology and restorative challenges that such patients can exhibit.

Introduction: Decalcification is a significant problem during fixed orthodontic treatment. Topical Fluorides can reduce or eliminate the problem, but the relative effectiveness of different treatments or combinations of topical fluoride preparations is unknown. This systematic review was undertaken to determine the effectiveness of topical fluoride preparations in preventing decalcification during fixed orthodontic treatment. Methods: A wide search of published and unpublished material in any language was undertaken by using general and specialist databases; key dental journals were searched by hand. Predefined inclusion criteria based on objective outcome measures of decalcification, duration of treatment, presence of a comparison group, and study design were applied to determine study selection. Included studies were double extracted onto predesigned data extraction sheets. Results and conclusions: By screening titles and abstracts, we identified 143 articles; after the inclusion criteria were applied, 7 reports (of 6 studies) remained. Differences in the methodologies and reporting made statistical analysis impossible. However, the use of topical fluorides in addition to fluoride toothpaste reduced the incidence of decalcification in populations with both fluoridated and nonfluoridated water supplies. Different preparations and formats appear to decrease decalcification, but there was no evidence that any 1 method was superior. There was some evidence that the potency of fluoride preparations might be important.

Literature on the treatment of obstructive sleep apnea in edentulous patients with a mandibular advancement splint is sparse. This clinical report describes a clinical and laboratory method of splint fabrication and discusses the rationale for its use.

The objective of this ex vivo study was to assess the use of resin-modified glass polyalkenoates and polyacid-modified composite resins, as orthodontic band cements.Plain stainless steel bands were cemented to 350 human extracted third molar teeth using 1 of 7 different cements. Following complete cement cure, half of each sample group was exposed to mechanical stress in a ball mill. Stressed and unstressed samples were tested in tension and the stress at which initial cement failure recorded. The mode of failure was recorded using an adhesive remnant evaluation.The mean band retention stresses offered by the cements studied ranged from 0.96 to 1.56 MPa. Fuji Ortho provided the highest mean band retention stress in "stressed" (1.56 MPa) and "unstressed" (1.45 MPa) states. Exposure to mechanical stress did not appear to significantly influence band retention or mode of cement failure for most cements. Fuji Ortho cement recorded the highest Weibull modulus for all cements tested. Virtually all samples failed at either the cement/enamel or cement band interface.Significant differences in band displacement stress values and mode of failure were demonstrated between the cements studied. However, generic comparisons were difficult to make.

The objective of this study was to evaluate the stresses generated in the bracket-cement-tooth continuum by a tensile load case when the physical and geometric properties of cement are varied. A 2-stage approach was used. In the first stage, a validated 3-dimensional finite element model of the bracket-cement-tooth system was constructed that consisted of 15,324 nodes and 2971 finite elements. Bracket base geometry was held constant; the physical properties (elastic modulus; Poisson's ratio) and geometry (lute thickness) of the cement varied. A simplified 2-dimensional model was then developed to investigate the localized effects of the cement lute thickness and the shape of the lute periphery on the stress distribution in the system. Small increases in stress were recorded under load within the cement as the rigidity of the cement increased. Similarly, Poisson's ratio values above 0.4 appeared to have a small influence on the major principal stresses in the impregnated wire mesh layer when a tensile force was applied. Variation in lute thickness was shown to have an influence on the distribution of major principal stresses within the cement lute. Increased stresses were recorded at the lute periphery as the lute dimensions increased. The morphologic features of the lute periphery also appeared to have had a significant effect on the performance of an orthodontic adhesive. Acute cementenamel angles resulted in an increased chance of singularity development and attachment failure. The physical properties and thickness of the cement lute and the shape of the cement lute periphery contribute to the stress distribution within the bracket-cement-tooth continuum and, therefore, the quality of orthodontic attachment provided. (Am J Orthod Dentofacial Orthop 2001;119:43-53)

This paper presents the results of investigations into the mechanical behaviour of fixed orthodontic brackets. Special attention has been paid to the detailed modelling of the interface between the bracket base and an adhesive by which attachment is made to the tooth surface. Properties of this interface were taken as design parameters with the aim of investigating their influence on the stress field induced during bracket removal at the end of the treatment. Stress-strain analysis was performed using a finite element program developed in-house.

The objective of the investigation was to develop a clinically valid three-dimensional computer model of the orthodontic bracket-cement-tooth continuum, and determine the magnitude and distribution of stresses generated by three different load cases. A three-dimensional finite element model of the bracket-cement-tooth system was constructed consisting of 15,324 nodes and 2,971 finite elements. The stresses induced in the bracket-tooth interface by a masticatory load, a peel force and a twisting couple were recorded. The maximum principal stresses resulting from occlusal and 'twisting' forces are distributed toward the lute periphery. Peel forces, applied to the bracket tie wing, are concentrated beneath the bracket stem. Twisting forces result in the highest enamel stresses. The quality of orthodontic attachment can be explained by the magnitude and distribution of major principal stresses within the cement and impregnated bracket base. Shear and shear/peel forces are most likely to induce crack propagation within the adhesive layer. However, when a twisting action is used to remove orthodontic brackets, enamel failure is most likely. A clearer insight into the complexity of the bracket-cement-tooth system has been provided by numerical and finite element investigations. Further investigations, evaluating the influence of bracket base designs and orthodontic cement physical and geometric properties are indicated. Refereed Scientific Paper

The primary objective of this investigation was to evaluate the crystal bonding technique and to: (1) study the effect on crystal size, coverage, and morphology of altering the concentration of lithium sulphate in a crystal growth solution; (2) investigate the potential for reattachment of brackets, following the use of the crystal growth technique; (3) assess the deterioration of the crystal growth conditioning solution with time; (4) investigate the influence of polyacrylic acid enamel pretreatment on the bond strength subsequently achieved with the crystal growth technique; and (5) confirm that the use of crystal growth solutions to attach orthodontic brackets, results in minimal enamel surface change on debond when compared to the acid etch technique. The results of the study suggest that altering the lithium sulphate concentration of the crystal growth solution results in little alteration in the size, morphology, and coverage of crystal produced. The crystal growth technique allows reattachment of orthodontic brackets with no obvious deterioration in bond strength and the crystal growth solution shows little deterioration in performance after storage for 2 years. However, the hope that the use of the crystal growth technique might be a routine and valid alternative to the acid etch technique could not be confirmed.

To investigate the feasibility of facial laser scanning in pre-school children and to demonstrate landmark-independent three-dimensional (3D) analyses for assessment of facial deformity in 5-year-old children with repaired non-syndromic unilateral cleft lip and/or cleft palate (UCL/P). Faces of twelve 5-year-old children with UCL/P (recruited from university hospitals in Cardiff and Swansea, UK) and 35 age-matched healthy children (recruited from a primary school in Cardiff) were laser scanned. Cleft deformity was assessed by comparing individual faces against the age and gender-matched average face of healthy children. Facial asymmetry was quantified by comparing original faces with their mirror images. All facial scans had good quality. In a group of six children with isolated cleft palate coincidence with the average norm ranged from 18.8 to 26.4 per cent. There was no statistically significant difference in facial asymmetry when compared with healthy children (P > 0.05). In a group of six children with UCL with or without cleft palate coincidence with the average norm ranged from 14.8 to 29.8 per cent. Forehead, midface and mandibular deficiencies were a consistent finding, ranging from 4 to 10mm. The amount of 3D facial asymmetry was higher in this group (P < 0.05). Facial laser scanning can be a suitable method for 3D assessment of facial morphology in pre-school children, provided children are well prepared. Landmark-independent methods of 3D analyses can contribute to understanding and quantification of facial soft tissue cleft deformity and be useful in clinical practice.

(1993). An Ideal Preformed Archwire? British Journal of Orthodontics: Vol. 20, No. 1, pp. 65-70.

A novel removable rapid maxillary expansion appliance is described for use in routine clinical practice. The laboratory construction and clinical technique is described, and the advantages of the appliance over conventional rapid expansion devices are highlighted.

The provision of orthodontic anchorage in the adult patient can be compromised due to reduced periodontal support, insufficient number of teeth and limited supra-gingival tooth tissue. Where tooth borne anchorage is unavailable for significant orthodontic movement implants represent a viable alternative. This paper describes the use of dental implants for orthodontic anchorage in a partially dentate patient with a severe unilateral cross-bite where orthognathic surgery was the only other realistic option. The implants were successfully engaged using a composite bridge and a modified quad helix appliance for correction of the malocclusion. Once orthodontics was completed the patient was restored using highly sintered ceramic crowns and bridges. This paper highlights the importance of the multi-disciplinary team and the close liaison between the restorative dentist, orthodontist and technician in treatment planning and provision.

Objectives: To evaluate the accuracy and reproducibility of a three-dimensional (3D) optical laser-scanning device to record the surface detail of plaster study models. To determine the accuracy of physical model replicas constructed from the 3D digital files. Design and setting: A method comparison study using 30 dental study models held in the Orthodontic Department, School of Dentistry, Cardiff University. Materials and methods: Each model was captured three-dimensionally, using a commercially available Minolta VIVID 900 non-contact 3D surface laser scanner (Konica Minolta Inc., Tokyo, Japan), a rotary stage and Easy3DScan integrating software (TowerGraphics, Lucca, Italy). Linear measurements were recorded between landmarks, directly on each of the plaster models and indirectly on the 3D digital surface models, on two separate occasions by a single examiner. Physical replicas of two digital models were also reconstructed from their scanned data files, using a rapid prototyping (RP) manufacturing process, and directly evaluated for dimensional accuracy. Results: The mean difference between measurements made directly on the plaster models and those made on the 3D digital surface models was 0.14 mm, and was not statistically significant (P=0.237). The mean difference between measurements made on both the plaster and virtual models and those on the RP models, in the z plane was highly statistically significant (P

In this fourth and final paper on the management of patients with congenitally missing teeth, the use of dental implants is considered. This group of patients often provides unique challenges when implant reconstruction is considered. Often a multidisciplinary approach is required involving orthodontists, oral surgeons and restorative dentists. The use of dental implant systems is a rapidly developing area of dentistry and its implications on hypodontia are discussed. This paper identifies the problems associated with a congenital absence of teeth and addresses their management in relation to the use of implants.The use of dental implants in hypodontia patients should always be considered as a treatment option. These groups of patients, however, require careful planning, often of a multidisciplinary nature, so that the timing of the various treatment modalities is seamless.

Restoration of spaces in hypodontia patients needs to take into account many factors including, the number of missing teeth, the distribution of space, the size of the teeth, and the age of the patient. This paper considers adhesive and conventional bridgework, as well as removal alternatives for the restoration of spaces. The various merits of each are discussed, together with treatment planning considerations for such cases.

Managing edentulous spaces in patients with congenitally missing teeth demands careful planning and, often, a multidisciplinary approach. Orthodontic tooth movement can be considered to close spaces as well as improve the distribution of available teeth. In this second paper, the advantages of a collaborative approach are discussed.

Purpose: This article describes construction of the average face and its application in the clinical environment. Subjects and Methods: A total of 72 children, mean age 11.8 years, were selected for the study. Laser-scanned images of the subjects were obtained under a reproducible and controlled environment with 2 Minolta Vivid 900 (Minolta, Osaka, Japan) optical laser-scanning devices assembled as a stereo pair. A set of left and right scanned images was taken for each subject and each scan took an average of 2.5 seconds. These scanned images were processed and merged to form a composite 3-dimensional soft tissue reproduction of the subjects using commercially-available reverse modeling software. The differences in facial morphology were measured using shell deviation color maps. The average face was used to compare differences between male and female groups and 3 subjects with craniofacial anomalies. Results: The difference between the average male and female face was 0.460 0.353 mm. The areas of greatest deviation were at the zygomatic area and lower jaw line, with the males being more prominent. The results of the surface deviation between the subjects with craniofacial anomalies were significant. Conclusions: The construction of the average face provides an interesting perspective into measuring changes in groups of patients and also acts as a useful template for the comparison of craniofacial anomalies.

ntroduction: The purpose of this prospective clinical trial was to evaluate the reliability of a 3-dimensional facial scanning technique for the measurement of facial morphology. Methods: A field study was conducted in 2 comprehensive schools in the South Wales region of the United Kingdom. Forty subjects, mean age 11 years 3 months, were analyzed for soft tissue changes at baseline (T1), within 3 minutes (T2), and 3 days later (T3) by using 2 commercially available Minolta Vivid 900 (Osaka, Japan) laser-scanning devices assembled as a stereo pair. Left and right images were merged to form the whole face, and these images were superimposed to assess the errors at T1 and T2, and T1 and T3. Results: The results showed that premerged left and right mean shell deviations were 0.38 � 0.14 mm for scans at T1, 0.31 � 0.09 mm at T2, and 0.34 � 0.12 mm at T3. The mean differences of the merged composite face were 0.31 � 0.08 mm between T1 and T2, and 0.40 � 0.11 mm between T1 and T3. Paired t tests showed no significant difference between these groups (P � .05). Shell deviation facial maps of the merged scans showed that 90% of the created composite facial scans were within an error of 0.85 mm. Conclusions: Capturing the soft tissue morphology of the face with this technique is clinically reproducible within 3 minutes and 3 days of the initial records.

Dental restoration adhering to the cavity exhibits fundamentally different load transfer mechanisms from non-adhering restorations. It is therefore questionable that traditional cavity designs are optimal from a purely mechanical point of view when working with composite materials. Drawing from general engineering experience, it can be hypothesised that smooth, well rounded designs with bevelled margins are superior. A finite element model is used in the present investigation to determine the stress field in four different cavity designs as it develops during the curing of the restoration. The results show that a significant reduction of the stress along the adhesive interface between the tooth and the restoration can be achieved through the use of a rounded cavity shape. They also show that the adoption of bevelled margins leads to a reduction of the stress concentration at this location. These results are confirmed by a set of experimental results published in the literature. It is concluded that adhering restorations will perform better from a mechanical point of view if an appropriate cavity shape is selected.

The objectives of the study were to isolate the bracket-cement interface, and to determine the influence of bracket base morphology and orthodontic bonding agent chosen on strength of adhesion. The bracket bases evaluated included 60, 80, and 100 single mesh bases, a double mesh base, and the Dynalock, and Mini Twin bases. The strength of interface provided by each of these bases with Concise, Transbond, Right On, and non-encapsulated Fuji Ortho LC cements, was measured in tension and recorded in Mega Pascals. The single-mesh bases performed well with either Concise or Right On (11*88-22*72 MPa) and, other than the 80-mesh bracket, relatively poorly with Transbond (2*18-5*15 MPa). With Fuji Ortho LC, the single mesh bases performed well (6*05-12*19 MPa). The double mesh base performed well with Right On (13*75 MPa), and reasonably well with Concise, Transbond, and Fuji Ortho LC (6*00-9*20 MPa). The Dynalock and Mini Twin Bases performed fairly well with all cements (8*87-17*16 MPa). It was concluded that the orthodontic bonding agent selected would appear to largely determine the bond strength achieved with a particular bracket base design. A definite trend was difficult to identify in this study, and it appeared that certain combinations of bracket base and bonding agent performed optimally. Particular base designs may allow improved adhesive penetration or improved penetration of curing light. Alternatively, the dimension and distribution of resin/cement tags prescribed by one base could promote a stress distribution that is better resisted by a particular adhesive.

There have been several reports of soft tissue injuries from orthodontic facebows in the dental and medical literature, but the magnitude of the problem in the UK and Eire has been previously investigated. In order to obtain information, questionnaires were distributed to 1682 Dental practitioners providing orthodontic treatment in the UK and Eire. A total of 1117 (66 per cent) replied. Of these 859 (77 per cent) reported using Kloehn type facebows. Thirty-one practitioners (3·6 per cent) gave details of 33 injuries from Kloehn type facebows. The results of this questionnaire are compared and discussed with previous reports in the dental and medical literature. The relative effectiveness of extra-oraltraction safety products is discussed.

This study evaluated the effect on the topography of the enamel surface of applying various solutions based on polyacrylic acid. This base solution consisted of 50 per cent aqueous polyacrylic acid (molecular weight 5000) and concentrated sulphuric acid (98 per cent). Previously, similar solutions have been found to initiate a crystal growth on the enamel surface and have been proposed as being suitable for the attachment of orthodontic brackets via a composite resin interface. The base solution was modified by the addition of various ionic salts: the sulphates of lithium, magnesium and potassium, respectively. Human pre molar teeth were then treated to a standard format and the effect on the enamel surface was examined by the use of a scanning electron microscope at × 500 and × 1500 magnification. The resultant micrographs of the specimens were presented to three independent observers who assessed the length, quality, and degree of coverage of the crystals. The solution containing potassium sulphate gave the longest crystals, whilst the greatest degree of coverage was obtained with the magnesium sulphate solution. Each solution was found to produce a consistent and recognizable morphology.