Eruption of third permanent molars after the extraction of second permanent molars. Part 1: Assessment of third molar position and size.

The eruptive path of third molars after extraction of second molars was examined in 63 patients. Panoramic radiographs from the start and the end of active treatment and 3 or more years after treatment were assessed. Study models were used to compare the size of the second and third molars and to assess the final position of the third molars. All third molars erupted; none became impacted. During eruption, maxillary third molar crowns uprighted and maintained their angulation as they came into occlusion. Mandibular third molar crowns continued to upright significantly mesiodistally after active treatment, with space closure the result of horizontal translation rather than mesial tipping. Further uprighting occurred once occlusion was established, although few became as upright as the second molars they replaced. However, mandibular third molar roots were frequently curved distally, thus the third molar crown position was invariably better than the overall tooth angulation would suggest, by 16.5 degrees on average. Model analysis (Richardsons' scoring system) showed 96% of mandibular and 99% of maxillary third molars erupted into a good or acceptable position. Limitations of this scoring system are discussed. The mesiodistal size of third molars was suitable to replace second molars; on average, mandibular third molars were 0.55 mm larger and maxillary third molars were 0.7 mm smaller than second molars.

Distal movement of buccal segments with the "en masse" removable appliance: its value in treating patients with mild Class II, Division 1 malocclusion. Part II: the model measuring system and results.

The model of 25 children with mild Class II, Division 1 malocclusions who had their upper buccal segments moved distally with an en masse appliance were measured at the beginning of treatment and at the completion of buccal segment retraction. A reflex microscope, interfaced to a personal computer, was adapted for this purpose. A custom-made jig and linear stepping motor permitted the recording of both buccal and incisal measurements of the teeth in occlusion, as well as individual arch parameters. Software was designed to record and calculate the required measurements. The method error associated with this approach ranged from 0.01 to 0.5 mm. Results indicated that mean distal movement of the buccal segments approximated 6 mm, equivalent to a full cusp of buccal segment retraction. A small spontaneous reduction in overjet was seen. The upper arch showed spontaneous alignment and increases in width, length, and perimeter. In the lower jaw, transverse expansion was accompanied by a small increase in arch perimeter. Arch length, however, was slightly reduced. It was concluded that the system was an acceptable method of recording occlusal changes during orthodontic treatment, supplementing routine cephalometry. Furthermore, a full unit of buccal segment retraction could be expected, by using a removable appliance/headgear technique.

Distal movement of buccal segments with the "en masse" removable appliance--its value in treating patients with mild Class II, Division 1 malocclusions: Part I, clinical techniques (how to do it).

This retrospective study examines the therapeutic changes during the buccal segment retraction phase of treatment in 25 children with mild Class II, Division 1 malocclusions and for whom distalization of buccal teeth was the treatment of choice. Where significant mandibular retrognathia was diagnosed clinically, a functional treatment approach was indicated, and these children were not included in this study. Therapy was carried out with an upper removable expansion appliance and extraoral traction. It will be shown in Part II of the investigation that a full unit of buccal segment retraction can be expected, with a combination removable appliance/headgear technique.

A comparative study of the effects of customized facemask therapy or headgear to the lower arch on the developing Class III face.

This retrospective, cephalometric study examined the effects of treatment in a group of 83 Class III, Skeletal III children, who were considered suitable for orthodontic correction of their malocclusions. All children completed therapy successfully: 44 individuals were treated with headgear to the mandibular dentition and for 39 a customized facemask was prescribed. These two groups were compared with 30 untreated Class III controls. Data were examined at the beginning and end of active treatment for the treated groups, and over a similar time interval for the controls. Where differences between the sexes were apparent, data for each sex are given separately. Where no significant differences were seen, data are pooled. In order to standardize the results, treatment (or observation) effects are presented as average changes per year. Surprisingly, despite the very different methods of applying the extra-oral force, the two treated groups showed strikingly similar therapeutic effects. The reverse overjet was corrected with little alteration in overbite. Upper incisors proclined whilst the lowers retroclined, becoming less prominent in relation to APo. The mandible hinged downwards and backwards, whilst the maxillary complex advanced. Lower face height increased more than would be expected by growth alone. Mirroring the hard tissue changes, the soft tissue profile improved and the relationship between the upper and lower lips became more harmonious. For only three parameters did the facemask children demonstrate a significantly better performance than their headgear peers: the overjet and the antero-posterior position of the lower lip and chin in females. It was concluded that, despite their differing approaches, the customized facemask and headgear to the mandibular dentition have very similar treatment effects. Both are clinically effective. However, treatment can begin earlier, and both the skeletal and profile changes are marginally superior when a facemask is worn.

Extrusion of the ectopic maxillary canine using a lower removable appliance.

The ectopic eruption and impaction of maxillary canines is a frequently encountered problem. The prevalence is estimated to be between 0.92% to 2.2%. It is found to be palatal to the dental arch in about 85% of cases and buccal only in about 15% of cases. Ericson and Kurol suggested that removal of the deciduous canine before the age of 11 years will normalize the position of the ectopically erupting permanent canine in 91% of cases if the canine crown is distal to the midline of the lateral incisor. We strongly endorsed this interceptive approach. Early recognition that a canine is erupting ectopically is extremely important. Ericson and Kurol estimate that in 0.71% of children in the 10 to 13 year age group, permanent incisors have resorbed because of the ectopic eruption of maxillary canines. Resorption may be found as early as 10 years but occurs most frequently in the age groups 11 to 12 years. In this article a simple, well-clasped lower removable appliance is shown to be an excellent base for using light elastics to move the impacted canine, first posteriorly away from the incisor roots and then vertically and buccally. A gold chain is bonded to the unerupted canine to provide a simple and flexible means of traction that ensures the canine erupts into a zone of attached mucosa with normal crown length.

Class III malocclusion: the post-retention findings following a non-extraction treatment approach.

A retrospective, cephalometric study was made of a group of 28 successfully treated, Class III, Skeletal III children, who were considered suitable for orthodontic correction of their malocclusions. All had undergone non-extraction therapy, involving a combination of upper incisor proclination and headgear to an intact mandibular dentition and were available for review at least 2 years after all treatment and retention had ceased. Only girls over the age of 16 years and boys above 18 years of age at the post-retention recall were included. Data were examined at the beginning and end of active treatment, and at least two years out of retention. Where differences between the sexes were apparent, data for each sex were given separately. Where no significant differences were seen, data were pooled. Overjet correction was achieved by a combination of upper and lower incisor movement with no alteration in overbite. This was accompanied by a downward and backward repositioning of the mandible, redirecting, rather than restricting mandibular growth. Post-retention, demonstrable skeletal development occurred in both male and female faces. Normal patterns of facial growth reasserted themselves, reversing many treatment effects. The mandible reverted to a more horizontal direction of development, but because no growth restriction had occurred during treatment, no 'catch-up' growth of the lower jaw could be shown. Mandibular growth exceeded that of the maxilla, and since upper and lower incisor inclinations remained unaltered, both overbite and overjet reduced. Reflecting the underlying growth pattern, the lips became more retrusive.

The treatment of severe 'gummy' Class II division 1 malocclusion using the maxillary intrusion splint.

This paper describes a modified Maxillary Intrusion Splint (M.I.S.) system which incorporates a near vertical pull headgear, and its use in the management of severe 'gummy' Class II division 1 malocclusion. The appliance was designed to reduce the visibility and vulnerability of the maxillary incisors in this difficult clinical situation by achieving the intrusion of maxillary teeth, restraining maxillary growth, and encouraging an element of subsequent forward mandibular rotation. The authors' initial experience using this system is presented in a retrospective cephalometric analysis of the lateral skull films of 26 treated patients contrasted with a similar number of comparable controls. The results showed that the principal effects of the M.I.S. were on the maxillary teeth giving decisive overjet control and incisor retraction with actual maxillary incisor intrusion. There was a similar effect on the maxillary molar and the M.I.S. provided effective en masse vertical control of the maxillary dentition. There was some degree of maxillary restraint in the M.I.S. group, but no noticeable difference in the change of mandibular position between the groups at the end of treatment. The possible reasons for this are discussed and suggestions made to improve this aspect of treatment in these patients.

Class III malocclusion: a comparison of extraction and non-extraction techniques.

A retrospective cephalometric study was made of the hard tissue changes in a group of 90 Class III, Skeletal III children, diagnosed as suitable for treatment by orthodontic means alone. Thirty-two were treated by a combination of upper incisor proclination and headgear to an intact mandibular dentition (Group 1), while in 28 the overjet was corrected with mid-arch extractions and Edgewise mechanics (Group 2). The remaining 30 children acted as controls (Group 3). Children were initially examined as male and female subgroups, and where no significant differences were seen data were pooled. In order to standardize the results, treatment/observation effects were presented as average changes per year. The three groups were essentially comparable pretreatment. Following overjet correction, the lower incisors uprighted in both groups, with an improved relationship to the A-Po line: the upper incisors were proclined in Group 1 only. Underlying skeletal changes were restricted to the mandible, which showed a downward and backward hinging, and an increase in lower face height. The improved mandibular position was significantly greater in the non-extraction group and was accompanied by an improvement in facial convexity. In addition, treatment could be started earlier and was completed in a significantly shorter time (Table 1). It would, therefore, appear that, in the short term at least, a non-extraction/headgear approach has advantages over a standard mid-arch extraction/Edgewise technique.

Criteria for approval of training programmes for senior registrars in orthodontics in the United Kingdom.

To be appointed as a consultant orthodontist in the British National Health Service requires a period of 3+ years in a higher training post as a senior registrar in orthodontics. Educational approval of these training posts is controlled by the Joint Committee for Higher Training in Dentistry. The detailed monitoring and requirements of senior registrar training posts are controlled by the Specialist Advisory Committee in Orthodontics and Paediatric Dentistry. Revised criteria for the approval of training programmes have recently been issued and are appended for the guidance of aspirant trainees, trainers and for the reader seeking an understanding of the UK title of 'Consultant Orthodontist'.

Future manpower requirements for orthodontics undertaken in the General Dental Service.

The fall in the number of births in England and Wales which took place between 1964 and 1977 is beginning to have an effect on the present-day demand for orthodontic treatment. Using the best available data a mathematical model has been used to predict the likely demand for orthodontic treatment in the General Dental Services of England and Wales from now until 2008. This suggests that there is likely to be a sharp decline in the number of new orthodontic patients presenting for treatment at practices limited to orthodontics during the next 5 years. The recent expansion in the number of places available for postgraduate study of orthodontics makes it extremely unlikely that the position will improve significantly thereafter. There can be little doubt that we are now producing too many orthodontic specialists even allowing for the increase in manpower which might be required to satisfy a future demand for higher standards of treatment.