Hypodontia Patients Research Articles

The management of severe hypodontia. Part 2: bone augmentation and the provision of implant supported prostheses

The first part of this series on severe hypodontia discussed the assessment of patients and factors to consider when treatment planning for the provision of conventional restorative solutions. This article discusses the provision of implant supported prostheses in the severe hypodontia patient who typically presents with inadequate bone volume and other associated dental and craniofacial anomalies. The role of bone augmentation to facilitate implant placement is discussed, in addition to prosthesis design and long-term maintenance. With careful case selection and planning most patients with severe hypodontia can be rehabilitated effectively, both functionally and aesthetically, with implant supported prostheses. In complex cases the involvement of a multidisciplinary team is needed to improve outcome. It should be highlighted that these patients will require ongoing follow up, maintenance and retreatment procedures over their lifetimes.

Impact of moderate and severe hypodontia and amelogenesis imperfecta on quality of life and self-esteem of adult patients

ObjectivesThe objective of this study was to investigate the impact of moderate and severe hypodontia and amelogenesis imperfecta on the quality of life and self-esteem of affected adult patients. MethodsForty one adult patients (aged 18–45 years) with clinical and radiological diagnoses of moderate to severe hypodontia and twenty seven patients diagnosed with amelogenesis imperfecta were age and gender matched with a control group of patients attending for routine dental care. Subjects completed the Oral Health Impact Profile [OHIP-49] and Rosenberg Self Esteem Scale. A paired t-test was used to analyse data; the test alpha level was set at P≤0.05. ResultsThe results for hypodontia patients were significantly different from controls in six out of the seven OHIP-49 domains, the exception being the Handicap domain. Total scores were also significantly different between the two groups (P=0.003). Self-esteem was not significantly different between the two groups (P=0.98).For amelogenesis imperfecta patients the results were significantly different from control patients in four out of the seven domains of the OHIP-49 and also in the total scores (P=0.01). When self-esteem was investigated there was no significant differences between the two groups (P=0.92). ConclusionsModerate to severe hypodontia and amelogenesis imperfecta have marked negative impacts on the Oral Health Related quality of life of this patient population relative to controls. However, self-esteem was not significantly affected.

Comparison of Mesiodistal Crown Dimension and Arch Width in Subjects with and without Hypodontia

Tooth agenesis is one of the most common anomalies in the development of the human dentition and may have wider associations in the development of the dentition including tooth size. This study aimed to compare mesiodistal crown dimension and arch widths between subjects with hypodontia and subjects without hypodontia (control group). Dental casts were measured of 55 hypodontia patients and 55 patients with total permanent dentition (control group). Tooth agenesis was evaluated for hypodontia, excluding the third molars, from the panoramic radiograph. Mesiodistal crown dimensions were recorded by measuring all erupted teeth on study models with a digital Mitutoyo caliper (Mitutoyo U.K. Ltd, United Kingdom). Patients with hypodontia had smaller mesiodistal tooth dimensions than the control group, and this difference was statistically significant (p < 0.05) for all teeth in both genders. Upper lateral incisors, lower central incisors, and lower second molars showed the highest difference in tooth dimension. Also, the intercanine and intermolar arch widths in the hypodontia group were statistically significantly reduced (p < 0.05) compared with the control group. The findings indicate that the mesiodistal crown dimensions and arch widths are reduced in hypodontia patients. This should be taken into account when planning orthodontic treatment. Congenital absence of permanent teeth has direct clinical implications. Early detection of the number of missing teeth and evaluation of the tooth size and arch width is of immense value in the planning and managing treatment with a multidisciplinary team approach to achieve an aesthetic and functional dentition and reduce the complications of hypodontia.

Evaluation of tooth size in patients with congenitally-missing teeth.

Background and aims Hypodontia is a common developmental abnormality of dentition. This study aimed to determine tooth width in patients affected with mild hypodontia and compare the results with a control group without tooth agenesis. Materials and methods The orthodontic records of 25 patients with congenital missing of one or two teeth (hypodontia group), and 25 subjects with full dentition (control group) were selected. The greatest mesiodistal width of each tooth was measured on the study models by a digital caliper. Tooth width measurements were compared between the groups using a student t-test at p < 0.05 of significance. Results Patients with hypodontia showed narrower teeth than the control subjects. The differences in tooth size between the two groups were statistically significant for the first and second premolars and first molar in the maxillary right and for the second premolar in the maxillary left quadrants (p < 0.05). In the lower arch, the first and second premolars and also first molar in both sides of hypodontia patients demonstrated significant reduction in tooth size compared to the control group (p < 0.05). Conclusion These findings suggest that patients with mild hypodontia have narrower teeth than normal subjects especially in posterior segments, which may have clinical implications during the orthodontic treatment process.

Tooth sizes in nonsyndromic hypodontia patients

To evaluate and compare the sizes of teeth in mild and severe hypodontia patients with those of healthy controls. Dental casts of 154 patients with two or more congenitally missing teeth were obtained. Patients were divided into two groups according to severity of hypodontia. Group I (mild) consisted of 118 patients with two to five missing teeth. Group II (severe) consisted of 36 patients with six or more missing teeth. In addition, a control group was included, which consisted of 50 patients who had an Angle Class I jaw relationship and no missing teeth. Mesiodistal and labiolingual dimensions of the teeth were measured with a digital caliper on dental casts. The independent-samples t-test was used to evaluate the effect of gender on measurements. Intergroup differences for mesiodistal and labiolingual dimensions were evaluated with analysis of variance and post hoc Tukey tests. Statistically significant differences were found between girls and boys with hypodontia in the mesiodistal dimension of the mandibular first premolar and the labiolingual dimension of the mandibular lateral incisor (P < .01). Mesiodistal and labiolingual width measurements of the teeth of hypodontia patients showed statistically significant differences compared with the control group (P < .05). Most teeth showed significant dimensional reductions in severe hypodontia compared with mild hypodontia (P < .05). The mesiodistal and labiolingual dimensions of teeth in both mild and severe hypodontia groups were smaller than those in control subjects. The reduction in size was more excessive in the severe hypodontia group. The teeth showing the greatest difference in tooth dimensions were the maxillary lateral incisor (in mesiodistal dimension) and the mandibular canine (labiolingual dimension).

Effects of hypodontia on craniofacial structures and mandibular growth pattern

IntroductionThis study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandible or in both jaws. The groups consistent of 50 children (33 girls, 17 boys) aged between 9 and 13.5 years were analyzed and assigned to three subgroups. Group 1 = upper jaw hypodontia. Group 2 = lower jaw hypodontia. Group 3 = hypodontia in both jaws.Materials and methodsEleven angular and three index measurements from lateral encephalographs and two linear measurements from dental blaster casts were calculated. All data was statistically analyzed, parameters with p < 5% were investigated for each subgroup respectively.ResultsIn comparison with standards the study group showed bimaxillary retrognathism and a reduction of the lower anterior facial height. Moreover both overbite and overjet significantly increased. Other values laid within the normal ranges. Evaluating results of the subgroups, differences in the means of SNA, SNB and overjet between the groups were observed.Analysis of the mandibular growth pattern revealed, that neither vertical nor horizontal patterns are dominant in hypodontia patients.ConclusionsIn certain dentofacial parameters differences between persons with hypodontia and such with full dentition exist. According to our findings agenetic teeth may have a negative influence on the saggital development of a jaw and the lower face and may be responsible for increased overbites. This should receive attention in orthodontic treatment of hypodontia patients.

Orthodontic Considerations in Restorative Management of Hypodontia Patients With Endosseous Implants

The use of implant-supported restorations in patients with hypodontia remains challenging and requires a multistage treatment that begins in late mixed dentition and continues into late adolescence. The aim of this article is to review the role of orthodontics in endosseous implant rehabilitation of patients with hypodontia. The MEDLINE, Web of Science, Scopus, Cochrane databases, and necessary scientific textbooks were searched for relevant studies and reviews, and as far as possible, they were only included if they had been cited at least once in the literature. Dental implants are susceptible to overloading as the periodontal ligament is absent and the proprioceptive nerve endings are either lacking or very limited. Patients with hypodontia may present with skeletal features such as short and retrognathic maxilla, prognathic mandible, and shorter lower anterior facial height, and they sometimes need orthognathic correction as part of their overall treatment. Dental problems vary and include bimaxillary retroclination of incisors, spacing, centerline discrepancies, microdontia, hypoplastic enamels, ankylosis of the retained primary teeth, overeruptions, and volume deficiencies of alveolar ridges. The challenges mentioned, as well as bone volume deficiencies, compromise the successful placement of implants. Orthodontic strategies and techniques, such as uprighting mechanics, extrusion/intrusion, delayed space opening, and orthodontic implant site-switching, can be used to create, preserve, or augment the implant site. After orthodontic site development, the final planned position of the teeth should be maintained with a rigid bonded retainer; overlooking this stage may compromise the implant site and require orthodontic retreatment.

The impact of hypodontia: a qualitative study on the experiences of patients

Congenital absence of teeth affects 2-6 per cent of the population, but its impact on quality of life (QoL) is not fully understood. The symptoms of hypodontia can vary and therefore also the treatment and management of this condition. Determining and understanding the possible impact of hypodontia on patients could inform and improve the management of such patients. A purposive sample of 10 participants aged 16-25 years (five males and five females) with mild, moderate, or severe hypodontia at various stages of treatment was recruited. The participants had previously completed a 49-item Oral Health Impact Profile (OHIP) questionnaire with summary scores ranging from 24 to 143. All subjects participated in semi-structured interviews, and these were transcribed and analysed using NVivo software. The results show that the role of hypodontia patients in the treatment decision-making process changes significantly as they move from childhood to adulthood. Participants indicated dissatisfaction with the lack of communication with dental services throughout early adolescence as they became more cognizant of their condition which in turn led to concerns with regard to appearance which impacted on their psychosocial well-being. Hypodontia patients expect improved communication with dental practitioners and services as they become more cognizant of their condition and wish to become more actively involved in the decision-making process regarding their current and future treatment.

Canine substitution for missing maxillary lateral incisors: The influence of canine morphology, size, and shade on perceptions of smile attractiveness

This study was conducted to determine whether variations in the morphology, size, or shade of maxillary canines would influence perceptions of smile attractiveness in patients with canines substituted for missing maxillary lateral incisors. A smiling photograph of a hypodontia patient who had had orthodontic space closure with maxillary canines replacing the lateral incisors was digitally modified to create a bilaterally symmetrical image. Four groups of images were created, digitally altering canine gingival height, crown tip height, canine width, and canine shade. Three groups of judges (40 orthodontists, 40 dentists, and 40 laypeople) ranked the images for smile attractiveness, also scoring the most and the least attractive of each of the 4 groups, and the most and least attractive of all images. Canine gingival height was the most attractive 0.5 mm below the gingival margin of the maxillary central incisor and progressively less attractive with increasing gingival height. Increasing canine width, increased canine tip height, and pointed canines were perceived to be unattractive. Brighter than normal shades of canines were preferred to darker shades. Narrow canine crowns were most frequently ranked as the most attractive overall, 1.5 mm narrower was preferred by the orthodontists and dentists, and 3.0 mm narrower was preferred by the laypeople. All 3 groups ranked the darkest image, 20 times darker than the original, most frequently as the least attractive image overall. There was good general agreement between orthodontists, dentists, and laypeople for all 4 parameters of smile attractiveness, although laypeople demonstrated greater intragroup variations. The morphology, size, and shade of the maxillary canine in patients having orthodontic space closure and lateral incisor substitution can have a marked effect on perceived smile attractiveness.

Editor's Comment and Q&A: Canine substitution for missing maxillary lateral incisors: The influence of canine morphology, size, and shade on perceptions of smile attractiveness

<h3>Introduction</h3> This study was conducted to determine whether variations in the morphology, size, or shade of maxillary canines would influence perceptions of smile attractiveness in patients with canines substituted for missing maxillary lateral incisors. <h3>Methods</h3> A smiling photograph of a hypodontia patient who had had orthodontic space closure with maxillary canines replacing the lateral incisors was digitally modified to create a bilaterally symmetrical image. Four groups of images were created, digitally altering canine gingival height, crown tip height, canine width, and canine shade. Three groups of judges (40 orthodontists, 40 dentists, and 40 laypeople) ranked the images for smile attractiveness, also scoring the most and the least attractive of each of the 4 groups, and the most and least attractive of all images. <h3>Results</h3> Canine gingival height was the most attractive 0.5 mm below the gingival margin of the maxillary central incisor and progressively less attractive with increasing gingival height. Increasing canine width, increased canine tip height, and pointed canines were perceived to be unattractive. Brighter than normal shades of canines were preferred to darker shades. Narrow canine crowns were most frequently ranked as the most attractive overall, 1.5 mm narrower was preferred by the orthodontists and dentists, and 3.0 mm narrower was preferred by the laypeople. All 3 groups ranked the darkest image, 20 times darker than the original, most frequently as the least attractive image overall. There was good general agreement between orthodontists, dentists, and laypeople for all 4 parameters of smile attractiveness, although laypeople demonstrated greater intragroup variations. <h3>Conclusions</h3> The morphology, size, and shade of the maxillary canine in patients having orthodontic space closure and lateral incisor substitution can have a marked effect on perceived smile attractiveness.

Frequency and characteristics of tooth agenesis among an orthodontic patient population

The objectives of this study were to investigate the prevalence and characteristics of tooth agenesis and the associated skeletal morphology and arch widths in a group of Turkish patients seeking orthodontic treatment. We designed a retrospective study composed of pre- and post-treatment panoramic radiographs and lateral cephalometric films of 3,341 patients (2,040 females and 1,301 males). Tooth agenesis was evaluated for hypodontia and oligodontia -excluding the third molars- from the orthopantomograms. The significance test for the differences in the skeletal morphology between hypodontia and non-hypodontia patients was performed using the Pearson chi-square and Student t-test. The prevalence of tooth agenesis was 4.6 percent for the Turkish orthodontic patient population. Tooth agenesis was found more frequently in females than in males, although this difference was not statistically significant (p>0.05). The most commonly missing teeth were the maxillary lateral incisors, followed by the mandibular second premolars and mandibular central incisors. Intercanine and intermolar widths in the maxillary and mandibular arches were significantly reduced in the hypodontia group compared with the control group (p<0.01). Tooth agenesis was statistically and significantly less in patients with skeletal Class II (p<0.01). There was no statistically significant difference in hypodontia patients in the vertical relationship of the jaws (p>0.05). The prevalence of tooth agenesis was found to be 4.6 percent for the Turkish orthodontic patient population (hypodontia 4.3% and oligodontia 0.3%), and was found more frequently in females. Intercanine and intermolar widths were significantly reduced in the hypodontia group for both jaws compared with the control group.

Dentofacial characteristics of patients with hypodontia

This study aims to identify distinctive dentofacial characteristics of hypodontia patients. For this purpose, 189 young hypodontia patients (cases) were divided into subgroups, based on criteria from literature. Normalised differences between cases and controls were calculated for various parameters of dentofacial form. Subsequently, cluster analysis was applied to disclose subsets of hypodontia patients with distinctive dentofacial features. The ANB angle, interincisal angle and lower anterior face height were consistently significantly different amongst the subsets. Four clusters of patients with an increasing number of missing teeth and distinctive dentofacial characteristics could be identified. Patients in cluster 1 display a high-angle facial pattern. Patients in clusters 2 and 3 exhibit markable dentoalveolar characteristics (a relatively small and a large interincisal angle, respectively). Patients in cluster 4 exhibited notable sagittal-skeletal discriminative features predominantly because of a retrognathic maxilla. The smallest nasolabial angle and lower anterior face height were seen in this cluster. It is concluded that the anterior-posterior relationship between the jaws, the interincisal angle and the lower anterior face height are discriminative parameters of dentofacial form in hypodontia patients. Patients with hypodontia can be clustered in four groups, each with distinctive vertical-skeletal, dentoalveolar and sagittal-skeletal characteristics. This categorisation of patients with hypodontia into meaningful groups may be useful for treatment planning, interdisciplinary communication and as a means of identifying groups of patients that qualify for reimbursement of costs. Other dental factors should be appreciated as well during restorative clinical decision making in patients with hypodontia.

Craniofacial profile in Southern Chinese with hypodontia

The association between craniofacial morphology and congenitally missing teeth is at present unclear. The aims of this study were to investigate whether hypodontia is associated with changes in the sagittal skeletal profile and to identify putative relationships between the skeletal profile and the severity of hypodontia. In a cross-sectional analytical study, the craniofacial structure and profile based on two-dimensional lateral cephalograms of Southern Chinese hypodontia patients (n = 49, 24 males, 25 females, mean age 16.4 years) and a comparison group without hypodontia (n = 41, 15 males, 26 females, mean age 16.7 years) were compared. The hypodontia patients were divided into three subgroups according to the severity of hypodontia (mild: < or =5, moderate: 6-9, and severe: > or =10 congenitally missing permanent teeth). All hypodontia patients had a significantly reduced mandibular plane, ANB, and face height compared with the control group (P < 0.05). A significant increase in chin thickness was also observed in the hypodontia patients (P < 0.05). As the severity of hypodontia increased from moderate to severe, a tendency to develop a retrognathic maxilla and a Class III skeletal relationship was noted in addition to the above features, making the already thick chin even more prominent. Statistically significant correlations (Pearson's correlation coefficient) were found between the number of missing teeth and SNA, NAFH, and ANB angles, the mandibular plane, chin thickness, and face height. In Southern Chinese subjects, hypodontia was associated with a shorter face, a flatter mandibular plane, a more pronounced chin, and a Class III skeletal profile. In severe hypodontia subjects, the maxilla was more retrognathic with a greater predilection to a Class III skeletal relationship.

Tooth size patterns in patients with hypodontia and supernumerary teeth

AimsAnomalies of tooth number may not be isolated conditions but may have wider associations in the development of the dentition including tooth size. This study aimed to examine links between hypodontia, supernumerary teeth and crown size, considering the effect on the development of the whole dentition and so increase understanding of the aetiology of these conditions. Methods and resultsThe patients, who were all of European ancestry, were 60 young adults (30 males and 30 females) with hypodontia and 60 age and sex matched controls together with 60 young adults (39 males and 21 females) with supernumerary teeth and 60 age and sex matched controls. Hand measurements of mesiodistal and buccolingual dimensions were made of the teeth on dental study models using Mitutoyo electric callipers. The mean value of two measurements was used and intra-operator and inter-operator reliability determined. Patients with hypodontia had smaller teeth than the control group and this difference was statistically significant (p<0.05) for all teeth except the MD dimensions of 13, 23, 24 and 44. The difference in size was greatest for the BL dimensions in hypodontia patients. Further, the greater the number of missing teeth the smaller the tooth size. The hypodontia patients also showed higher variability in tooth dimensions than the control group. Patients with supernumerary teeth had larger teeth than the controls, with the greatest differences in the MD dimensions. In both hypodontia and supernumerary patients the differences in tooth size were generalised throughout the dentition. ConclusionsIn anomalies of tooth number the size of teeth is also involved. In patients with hypodontia and supernumerary teeth the crown size of the whole dentition is affected. These findings are compatible with a multifactorial aetiology of these conditions.

A preliminary evaluation of pre-treatment hypodontia patients using the Dental Aesthetic Index. How does it compare with other commonly used indices?

There is currently no specific occlusal index related to hypodontia and there is a paucity of published literature on this subject. The aim of this study was to determine the relationship, if any, between the Peer Assessment Rating (PAR) Index, the Index of Complexity, Outcome and Need (ICON), and the Dental Aesthetic Index (DAI) score and the severity of hypodontia. All new patients attending the Newcastle Dental Hospital hypodontia clinic between February 2002 and March 2003 were included in the study. Of the 60 patients, two were excluded as the models were unavailable and one because they were predominantly in the primary dentition, making scoring impractical. The patient casts were scored with respect to PAR, ICON, and DAI. The mean patient age at presentation was 12 years, with a standard deviation of 1.89 and a range of 9-16 years, and a female to male ratio of 1.1:1. A significant positive correlation, using Kendall tau b, was found between the number of missing teeth, excluding third molars, and the DAI score (tau = 0.215, P = 0.027). There was no significant positive correlation between PAR (tau = -0.186, P = 0.056) and ICON (tau = 0.017, P = 0.861) score and the number of missing teeth. The results of this investigation indicate that further research is required in order to assess if the DAI could be used to determine whether or not to refer hypodontia patients for specialist advice.

Clinical analysis of simple hypodontia

To compare and analyse the distribution and characteristic of born missing teeth. A total of 183 simple hypodontia patients was reviewed and statistically analysed. There was no significant difference in the number of missing teeth between different sexs (P > 0.05), and there was also no significant difference in the number of missing teeth among different sites (maxilla, mandible or left and right sides) (P > 0.05). The mandibular second premolar was the most frequently missing tooth. The missing molars were more commonly seen in oligodontia patients who had six missing teeth or beyond than hypodontia patients with less than six missing teeth (P < 0.05). Each hypodontia patient has his own clinical manifestation, and appropriate treatment should be planed accordingly for these patients.

The influence of varying maxillary lateral incisor dimensions on perceived smile aesthetics

The aim of this study was to determine the influence of varying the dimensions of the maxillary lateral incisors on perceived smile aesthetics. Clinical study. Postgraduate dental teaching hospital. A photograph of a female smile displaying only the lips and teeth was digitally altered. First, the width of the maxillary lateral incisors, in proportion to the central incisor, was altered at 5% intervals to produce six images (52%, 57%, 62% [the 'golden proportion'], 67%, 72% and 77%). In a second group, the length of the lateral incisor was altered at 0.5 mm increments to produce five images with the lateral incisor 0.5 mm, 1 mm, 1.5 mm, 2 mm and 2.5 mm shorter than the adjacent central incisor. The photos were ranked from 'most attractive' to 'least attractive' by 41 hypodontia patients, 46 non-hypodontia 'control' patients and 30 dentists. The 67% followed by the 72% lateral-to-central width proportions were the 'most preferred' by all groups. A maxillary lateral incisor that is 1-1.5 mm shorter than the central incisor was the 'most popular' maxillary lateral incisor length. The very short and very long maxillary lateral incisor was consistently perceived as 'least attractive'. There is no evidence to suggest that the golden proportion should be considered the ideal aesthetic standard when creating space for the replacement of missing lateral incisors.

Modern Restorative Management of Patients with Congenitally Missing Teeth: 3. Conventional Restorative Options and Considerations

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.

Management of hypodontia

Objective To analyse the clinical performance and factors influencing the survival of resin-bonded bridgework provided for hypodontia patients with missing maxillary lateral incisors, following orthodontic treatment to open, maintain or redistribute the missing tooth space. Design A retrospective analysis of patients treated at a single centre using case notes with all patients invited for review to corroborate findings. Setting Departments of Orthodontics, Child Dental Health and Restorative Dentistry, Newcastle upon Tyne Dental Hospital and School. Subjects and methods Between 1989-2000, 59 suitable hypodontia patients were identified of whom 45 had complete records. For these patients 73 resin-bonded bridges (RBBs) were provided. Following invitation, 24 patients attended for a review appointment. The survival of the RBBs, grade of operator providing treatment, duration of post-orthodontic retention, the influence of design, presence of pontic contact in static and dynamic excursions, and the effect of habits were assessed. Life table, Kaplan-Meier and Cox regression analysis were carried out for the 73 RBBs with complete records. A separate analysis of the RBBs provided for patients who attended for the invited review did not show a higher failure rate than those patients who did not attend. Therefore both sets of data were combined. Results Of the 73 RBBs provided, 30 had debonded on at least one occasion (41.1%), six of these debonds were due to trauma (20%). The mean survival time of all the restorations was 59.3 months, with a median survival time of 59 months. Senior members of staff (Consultant, Senior Lecturer or Specialist Trainee) provided most restorations (n = 39) and achieved the highest mean survival of 72.6 months and median survival time of 100+; months. RBBs provided by junior staff and students had significantly lower survival times (p <0.05) compared with senior staff. Risk of failure was 3.9 times greater with junior staff and 2.5 times greater with students (p = 0.01 and p = 0.02, respectively). Analysis of all the other factors investigated showed no statistical difference in survival times or in hazard ratios. Analysis of fixed/fixed versus cantilevered bridges was limited by the number of fixed/fixed bridges (n = 11), and only two cantilevered bridges with multiple abutments were provided; both failed within one month. Conclusion RBBs provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors can for many patients be an acceptable and definitive restoration. Experienced staff achieved the best results, but why this should be was not explained by the individual factors analysed in this study.

Survival of resin-bonded bridgework provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors

To analyse the clinical performance and factors influencing the survival of resin-bonded bridgework provided for hypodontia patients with missing maxillary lateral incisors, following orthodontic treatment to open, maintain or redistribute the missing tooth space. A retrospective analysis of patients treated at a single centre using case notes with all patients invited for review to corroborate findings. Departments of Orthodontics, Child Dental Health and Restorative Dentistry, Newcastle upon Tyne Dental Hospital and School. Between 1989-2000, 59 suitable hypodontia patients were identified of whom 45 had complete records. For these patients 73 resin-bonded bridges (RBBs) were provided. Following invitation, 24 patients attended for a review appointment. The survival of the RBBs, grade of operator providing treatment, duration of post-orthodontic retention, the influence of design, presence of pontic contact in static and dynamic excursions, and the effect of habits were assessed. Life table, Kaplan-Meier and Cox regression analysis were carried out for the 73 RBBs with complete records. A separate analysis of the RBBs provided for patients who attended for the invited review did not show a higher failure rate than those patients who did not attend. Therefore both sets of data were combined. Of the 73 RBBs provided, 30 had debonded on at least one occasion (41.1%), six of these debonds were due to trauma (20%). The mean survival time of all the restorations was 59.3 months, with a median survival time of 59 months. Senior members of staff (Consultant, Senior Lecturer or Specialist Trainee) provided most restorations (n = 39) and achieved the highest mean survival of 72.6 months and median survival time of 100+ months. RBBs provided by junior staff and students had significantly lower survival times (p <0.05) compared with senior staff. Risk of failure was 3.9 times greater with junior staff and 2.5 times greater with students (p = 0.01 and p = 0.02, respectively). Analysis of all the other factors investigated showed no statistical difference in survival times or in hazard ratios. Analysis of fixed/fixed versus cantilevered bridges was limited by the number of fixed/fixed bridges (n = 11), and only two cantilevered bridges with multiple abutments were provided; both failed within one month. RBBs provided for post-orthodontic hypodontia patients with missing maxillary lateral incisors can for many patients be an acceptable and definitive restoration. Experienced staff achieved the best results, but why this should be was not explained by the individual factors analysed in this study.