Fixed Appliances
These appliances are attached to the crowns of teeth and allow correction of rotations, bodily movements of teeth and alignment of ectopic teeth. They have increased in sophistication enormously over the past 10-15 years and together with advancements in arch wire technology are capable of producing a very high level of treatment result. Simultaneous multiple tooth movements can be achieved, invariably creating a better treatment outcome than can be achieved with removable appliances. Although...
Tmd
Instability of tooth position Indeed intercuspal position rarely coincides with retruded contact position in a good occlusion and it has yet to be shown that canine guidance has an effect of preventing or curing TMD. A natural dentition with canine guidance will tend to become group functioning with time as the canines wear. Furthermore canine guidance does not seem to offer any protection against TMD.12 Although canine guidance is often advocated as the functioning mode of choice, it is often...
Canines
These teeth are rarely considered for extraction unless very ectopic Fig. 8 . The loss of a canine makes canine guidance impossible and may compromise a good functional occlusal result. Contact between a premolar and lateral incisor is often poor and canines can act as ideal abutment teeth because of their long root length and resistance to periodontal problems. Palatally ectopic canines can sometimes be in unfavourable positions for alignment, and lower ectopic canines often require extraction...
Dental Health
Surprisingly there is no strong association between dental irregularity and dental caries or periodontal disease. It seems that dietary factors are much more important than the alignment of the teeth in the aetiology of caries. Although straight teeth may be easier to clean than crooked ones, patient motivation and dental hygiene seems to be the overriding factor in preventing gingivitis and periodontitis. That said, few of the studies that have investigated the link between crowding and...
Diagnosis
It is easy to miss non-eruption of the permanent canines, but there are some markers which should increase suspicion of possible impaction. Any case with a deep bite, missing lateral incisors or peg-shaped upper lateral incisors needs a detailed examination. Figure 1 shows such a case and in this instance both canines were significantly impacted on the palatal aspect. The retained deciduous canine is self evident. Other clues include root and crown positions. Figure 2 shows a lateral incisor...
Traumatised Teeth
Traumatised, fractured, intruded or avulsed teeth may sometimes benefit from an orthodontic input. Teeth, which are fractured or intruded, may need extrusion, and this can be accomplished by using a number of different appliances and techniques. Figure 4 is an example of an upper appliance being used to extrude two unerupted upper incisors as an interceptive form of treatment. The upper permanent lateral incisors had already erupted a clear sign that something was wrong. A supernumerary tooth,...
Profile damage
Extraction of premolars has been condemned by some with very little evidence, as altering the facial profile of the patient.31 A large number of studies have shown that there is no significant difference in profiles treated by extraction or non extraction means. Boley et al 2 found that neither orthodontists nor general dentists could distinguish between extraction and non extraction treatment by looking at profile alone. A recent review examined the effects of orthodontics on facial profie and...
Second molars
Thomas et al.21 provided a succinct summary on the role of loss of second molars in orthodontic treatment. They state that all other teeth should be present with the third molars of normal size, shape and in a good position to erupt. Mild lower labial segment crowding may be effectively treated by loss of second molars, however they should not be considered in the treatment of moderate or severe crowding. Second molar loss may be undertaken under the following circumstances To facilitate the...
Poor appliance design
Failure to adequately retain the appliance, or incorporate as many teeth into the anchor block as possible are common causes of anchorage loss. If fixed appliances are used, as many Fig. 8a A neck strap. Note the snap away safety mechanism Fig. 8b An occipital high pull headgear again with a snap away safety system Fig. 8c A variable pull Interlandii headgear. A rigid plastic strip is employed as a safety mechanism to prevent the facebow disengaging from the molar bands and coming out of the...
Interceptive Measures For Canines
One of the most significant publications in the orthodontic literature came from Ericson amp Kurol 1988 1 who demonstrated that extraction of upper deciduous canines where the upper permanent canines were developing on the palatal aspect, resulted in nearly an 80 chance of correcting the impaction. The paper was very specific about what types of malocclusions this could be applied to. Nearly all the cases were Class I with no incisor crowding. This is important to emphasise, a subsequent...
Overbite reduction
Removable appliances are very effective in correcting a deep overbite, especially in a growing patient. An upper removable appliance with an anterior bite plane is used which disengages the molars by 2-3 mm whilst at the same time establishing lower incisor contact with the bite plane Fig. 6 . Eruption of the posterior teeth produces a reduction in the overbite. It is essential that the inter-incisor angle is corrected at the completion of treatment so that an occlusal stop between the upper...
Occlusal Problems
Orthodontics can be used to try and produce an optimal occlusion, and there are many situations in which this can be used.2 The occlusion can be adjusted to provide canine guidance, and eliminate non-working side interferences. In situations where anterior open bites exist, it is occasionally possible to close these down without the need to resort to surgery.3 Sometimes the occlusion can damage the teeth and supporting tissues. Figure 8 is an example of a patient with a unilateral cross bite...
Conclusions 1
Many factors influence the choice of teeth for extraction and careful treatment planning in conjunction with good patient co-operation, appliance selection and management of the treatment are essential if an acceptable, aesthetic and functional occlusion is to be achieved. 1. Angle E H. Treatment of malocclusion of the teeth and fracturesof the maxillae, Angle's system. Ed 6, 1900 S.S. Philadelphia White Dental Manufacturing Co. 2. Wolff J. DasGesetzderTransformationder Knochen. Berlin...
B A Degree of crowding
Class I. The lower incisor edges occlude with or lie immediately below the cingulum plateau middle part of the upper central incisors. Class II. The lower incisor edges lie posterior to the cingulum plateau of the upper central incisors. There are two divisions Division 1 there is an increase in the overjet and the upper central incisors are usually proclined. Division 2 the upper central incisors are retroclined. The overjet is usually minimal but may be increased. Class III. The lower incisor...
Orthodontics And Temporomandibular Dysfunction
Relatively recently, orthodontists have been concerned about the possibility of a link between the orthodontic treatment they provide and tem-poromandibular dysfunction TMD which is a Temporomandibular joint problems are not caused or cured by orthodontic treatment Litigation forced orthodontists into generating objective scientific research into the effects of orthodontic treatment common finding in the population. Longitudinal studies show that the prevalence of signs and symptoms of TMD...
What Are The Best Radiographic Views To Locate Canines
Most patients undergoing routine orthodontic screening will have a dental pantomogram. Location of tooth position requires two radiographs in different positions. In the interests of radiation hygiene it is sensible to use this as a base x-ray and to take further location radiographs in relation to the dental pantomogram. An anterior occlusal radiograph allows this and the principle of vertical parallax can be used to locate the position of the canine. The tube has to shift in order to take an...
Infective endocarditis
Patients at risk of endocarditis should be treated in consultation with their cardiologist and within the appropriate guidelines.35,36 The patient must exhibit immaculate oral hygiene, antibiotic cover will be required for invasive procedures such as extractions, separation, band placement and band removal. It is recommended that bonded attachments are used on all teeth to negate the need for antibiotic cover for both separator and band placement, as well as removal. This also reduces the risk...
Other Impactions
The only other impactions to be considered in a general form are first molars. These may impact in soft tissue and it is sometimes worth considering occlusal exposure where a first molar has not erupted. This usually occurs in the upper arch and can be accepted if the oral hygiene is good with minimal caries experience. Impacted molars of this type quite frequently self correct before or during eruption of the second premolar. There may also be primary failure of eruption and if the tooth fails...
First molars
First permanent molars are often the first permanent teeth to erupt into the mouth. Their deep fissure morphology predisposes them to caries and poor tooth brushing combined with a high sugar intake, may result in gross caries. Heavily restored or decayed first molars should be considered for removal over other non-carious teeth Fig. 12 . First molars extraction requires careful planning. Their position in the arch means that whilst relief of premolar crowding is achieved the space created is...
Vertical dimension
This dimension gives some indication of the degree of overbite. The vertical dimension is usually measured in terms of facial height and the shorter the anterior facial height the more likely it is that the patient will have a deep over-bite. Conversely the longer the facial height the more the patient is likely to have an anterior open bite. Deep overbites associated with a short anterior facial height and open bites with long face heights are difficult to correct with orthodontics alone. The...
Tipping
One of the major uses of removable appliances is to move one incisor over the bite as shown in Figs 2a-d. A simple upper removable appliance utilized a 'T' spring constructed from 0.5 mm wire activated 1-2 mm which delivered a force of about 30 g to the tooth. After only a few weeks the cross bite was corrected without the need for complex treatment. Note the anterior Fig. 1a-c A 9 year-old patient with an anterior open bite caused by a thumb sucking habit. Note the wear on the thumb as a...
Inter maxillary anchorage
Teeth in the opposite arch can provide very useful and important sites of anchorage control as Figs 4a,b illustrate. Good inter-digitation of the buccal teeth can help prevent mesial movement of the buccal segment. Although there is only anecdotal evidence to support this view, many clinicians feel this can be a useful source of anchorage. The second way that opposing teeth can be used is by means of elastics or springs running from one arch to the other. Class II elastics Fig. 4c run from the...
Enamel wear
Wear of enamel against both metal and ceramic brackets abrasion may occur. It is common on upper canine tips during retraction as the cusp tip hits the lower canine brackets Fig. 5 . It may also be seen on the incisal edges of upper anterior teeth where ceramic brackets are placed on lower incisors.17 Ceramic brackets are very abrasive and therefore contraindicated for the lower anterior teeth where there is any possibility of the brackets occluding with the upper teeth, bearing in mind that...
Retrieval And Preservation Of Anchorage
Extra-oral devices can be used for distal movement as well as anchorage reinforcement. For anchorage control wearing the headgear at night-time only is usually enough. In order to produce distal movement, the patient should wear the appliance in excess of 12 hours usually for the evenings as well as at nighttime. While some practitioners increase the force levels for distal movement purposes, it is our experience that this is not necessary and a force of approximately 250-300 g per side is...
Supplemental teeth
There are some conditions which have a genetic basis where impacted teeth are seen more frequently and this includes cleidocranial dysplasia, cleft lip and palate, gingival fibromatosis and Down's Syndrome. It is worth remembering that most central incisors should have erupted by the age of 7 and lateral incisors by the age of 8. Surprisingly, most referrals for impacted maxillary incisors are when the patient is 9 years of age. This delay in diagnosis could potentially influence the outcome...
Anteriorposterior AP
Although precise skeletal relationships can be determined using a lateral cephalostat radiograph, many practices do not have this facility and it is important to be able to assess the skeletal relationships clinically. To assess the AP skeletal pattern the patient has to be postured carefully with the head in a neutral horizontal position Frankfort Plane horizontal to the floor . Different head postures can mask the true relationship. If the head is tipped back the chin tends to come further...
Correction of canine position Favourable indications for correction of impacted
Canines are moved most easily into their correct position if the root apex is in a favourable position. If the tooth lies horizontally it is extremely difficult to correct this and generally the closer the tooth to the midline the more difficult the correction will be. Treatment is nearly always lengthy and can damage adjacent teeth. Figure 13 shows a lateral incisor adjacent to a palatally impacted canine where the opposite reaction to Fig. 13 A lateral incisor adjacent to a palatally impacted...
Missing Teeth 1
The choice in these cases is usually to recreate space for the prosthetic replacement of missing teeth, or to close the space instead. If an upper central incisor is missing then the usual choice is to open up the space and put in some form of prosthesis. If the space is closed and the lateral incisor is placed in the central incisor site, then camouflage is difficult because of the small width of the lateral that results in an unsightly emergence angle of the crown. In cases where an upper...
Tempromandibular dysfunction TMD
Much attention in the literature has been focused on the relationship between TMD and orthodontic treatment. Whilst TMD is common in the orthodontic aged population whether orthodontic treatment is carried out or not, there is no evidence to support the theory that orthodontic treatment causes TMD or cures it.29 Pre-existence of TMD should be recorded, and the patient advised that treatment will not predictably improve their condition. Some patients may suffer with increased symptoms during...
Functional Appliances
These are powerful appliances capable of impressive changes in the position of the teeth. They are generally used for Class II Division I malocclusions although they can be used for the Fig. 12c Upper first and lower second premolars were extracted and the canines surgically exposed Fig. 12d A tri-helix was used to expand the upper arch and a sectional fixed appliance used to pull the canine into the line of the arch Fig. 12a, b Pre treatment photographs of a patient with palatally impacted...
Should We Extract Second Molars As Part Of Orthodontic Treatment
There are said to be many advantages in extracting second molars as part of orthodontic treatment. These advantages include the following Less detrimental to facial profile Facilitates the eruption of third molars Spontaneous relief of crowding in the premolar region Prevents crowding in a well aligned lower arch Aids distal movement of the buccal segments with extra oral traction Functional occlusion is better It can be seen that it is an impressive list of advantages There are however several...
Conclusions
Clearly there are a number of sources of potential iatrogenic damage to the patient during orthodontic treatment. However, severe damage is rare. Severe malocclusions have more to benefit from treatment than less severe malocclusions, and motivation between such groups may vary. Individuals should be assessed for risk factors for all aspects of care. Lack of treatment can result in damage, physical or psychosocial. Discontinuation of treatment without full correction of the malocclusion,...
The Extraction Versus Nonextraction Debate
The extraction of teeth as part of orthodontic treatment continually causes controversy. Teeth are extracted for several reasons in orthodontics. The most common reason for extraction is the relief of crowding and the need to create space to gain good alignment of the teeth. The reduction of overbite and the correction of an increased overjet to obtain a Class I incisor relationship are also important issues to consider where extractions will be required. Edward Angle was very influential...
Bone Bending Piezoelectric And Magnetic Forces
There was considerable interest in piezoelectricity as a stimulus for bone remodelling during the 1960s. This arose because it was noted that distortion of crystalline structures generated small electrical charges, which potentially may have been responsible for signalling bone changes associated with mechanical forces. The interest therefore in 'electricity' and bone was considerable. Magnets have been used to provide the force needed for orthodontic tooth movement. Classically an unerupted...
Transplantation
Canine transplantation has received poor press in the past. Many of the problems arose because the canines were transplanted with a closed apex. These teeth were seldom followed up with root fillings on the basis that they would revas-cularise. This is unlikely through a closed apex and it is preferable to treat them as if they were non-vital. Transplantation is an option which should only be reserved for teeth that are in almost an impossible position and where there is extensive hypodontia or...
Enamel trauma
When placing appliances careless use of a band seater can result in enamel fracture. Care is required when large restorations are present since these can result in fracture of unsupported cusps.14 Debonding can also result in enamel fracture, both with metal and ceramic brackets Fig. 4 .15,16 Care must always be taken to remove brackets and residual bonding agents appropriately to minimise the risk of enamel fracture. The use of debonding burs has the potential to remove enamel, especially in...
D RobertsHarry1 and J Sandy2
There are various reasons for offering patients orthodontic treatment. Some of these include improved aesthetics, occlusal function and the long-term dental health. Consultant Orthodontist, Orthodontic Department, Leeds Dental Institute, Clarendon Way, Leeds LS2 9LU 2Professor in Orthodontics, Division of Child Dental Health, University of Bristol Dental School, Lower Maudlin Street, Bristol BS1 2LY Correspondence to D. Roberts-Harry E-mail robertsharry btinternet.com Consultant Orthodontist,...