Face height and tooth eruption in adults--a 20-year follow-up investigation

Longitudinal changes of the natural craniofacial and dentoalveolar complex in the fourth decade of life

INTRODUCTION

This study aimed to longitudinally examine the changes in craniofacial and dentoalveolar regions during the third and fourth decades of life.

METHODS

The data from this study constitute the cephalometric films and plaster models of 8 female and 8 male dental students or dentists. The mean chronological ages of the subjects at the first observation period was 22.09 years for females and 22.64 years for males. The material was collected over 3 intervals: 1985-1989, 1998-2000, and 2016-2017. The observation period was approximately 28 years. Acquired cephalometric recordings and dental models were assessed for subjects in their 20s (baseline), 30s, and 40s. Maxillary, mandibular, maxillomandibular, soft-tissue, and dentoalveolar cephalometric variables were measured with a cephalometric analysis software, and dental cast measurements were made with a digital caliper. Changes in the cephalometric films and dental casts were evaluated statistically.

RESULTS

Statistical analysis showed that the length of the midfacial region increased with age. The height of the lower face increased significantly in females and the mandible can be seen mildly rotating to the posterior as it increased in length. The nose moved slightly forward and downward in males and females. Upper lip height was significantly increased in females; however, there was a significant reduction in upper lip thickness for males and females. Soft-tissue pogonion measurements showed a significant forward and downward chin movement in females. Overjet was significantly increased in females, whereas the mandibular arch length was significantly decreased for both sexes, although it was more prominent in females. There was a loss of space in the anterior segments of males and females, resulting in increased crowding. However, the loss of space was only significant in the mandible.

CONCLUSIONS

We observed significant changes in skeletal, soft-tissue, and dentoalveolar variables of subjects in their third and fourth decades of life. The fact that many changes have occurred throughout this study demonstrates that the process of maturation and aging is ongoing.

Adjacent tooth migration after maxillary first molar loss in patients with sinus augmentation: A retrospective research

PURPOSE

The objectives of this study are to: (1) investigate the extent of antagonistic and distal neighboring tooth migration in the maxillary posterior single tooth-missing site during the healing period of bone augmentation and implant surgery; (2) identify factors associated with tooth migration.

MATERIALS AND METHODS

One hundred and forty-three cases that lost the maxillary first molar were included, and their CBCT data during the edentulous period were obtained. Dentition models were reconstructed from CBCT, and superimpositions were performed, followed by measuring migration distances and calculating migration rates of antagonistic and distal neighboring teeth. Factors were analyzed using multivariate generalized estimating equations (GEE).

RESULTS

The mean migration distances were 208 ± 137 μm and 403 ± 605 μm for antagonistic teeth and distal teeth, and the mean migration rates were 26.8 ± 21.2 μm/month and 48.5 ± 76.7 μm/month, respectively. One hundred and nineteen out of 143 distal neighboring teeth migrated toward the edentulous site, and all antagonistic teeth migrated occlusally. Occlusal contact loss and chronic apical periodontitis both significantly accelerated antagonistic tooth migration (p < 0.05), the latter also accelerated distal tooth migration (p < 0.05). Besides, the displacement of the distal teeth was somewhat accelerated by the impacted adjacent third molar and root protrusion into the sinus.

CONCLUSIONS

The neighboring teeth tend to migrate toward the edentulous gap in the maxillary posterior region. Occlusal contact loss and chronic apical periodontitis are two significant risk factors for accelerating antagonistic tooth migration, and for distal teeth, chronic apical periodontitis is the risk factor. The impacted adjacent third molar and root protrusion into the sinus are also potential risk factors for accelerating the migration of the maxillary distal tooth. Thus, to prevent maxillary edentulous gap reduction, the factors mentioned above should be taken into consideration when planning treatment flow.

Skeletal and soft-tissue changes in humans with untreated normal occlusion throughout lifetime: a systematic review

Age-related skeletal and soft-tissue changes are important in orthodontics, especially due to the increase of adult patients seeking treatment. The aim of this study is to assess the available evidence regarding age-related skeletal and soft-tissue changes in untreated Angle Class I. Articles studying skeletal and soft-tissue changes in orthodontically untreated subjects with Angle Class I and comparing them between age groups were included. Studies focusing on a single age group or in languages other than English were excluded. Risk of bias was assessed with both the MINORS and ROBINS-I tools. 50 studies were included, showing high methodological heterogeneity and a lack of information in subjects over 60 years old. In subjects with Angle Class I, the mandibular plane inclination was reported to reduce from 7 and 20 years old, while the anterior and posterior facial height continue to increase in late adult life. The anterior cranial base length increases until 20 years old, afterwards decreasing slowly until late adulthood. Nasal width increases and the nasolabial angle decreases during adolescence. Upper lip length and lower lip length increase from 6 to 18 years along with retrusion of the lips in late adulthood. Age-related skeletal and soft-tissue changes are documented in the literature from childhood until the fifth decade of life, but studies mostly focus on subjects until 20 years old. Changes after the second decade of life are studied only for the vertical and sagittal dimensions. No changes are reported in the transversal dimension beyond 15 years for neither skeletal nor soft tissues. Well-designed, long-term prospective cohort studies considering all three dimensions of skeletal and soft tissues are needed for confirmation of these findings (PROSPERO: CRD42020203206).

Impact of maxillofacial growth on implants placed in adults: A narrative review

OBJECTIVE

To determine the effect of lifetime maxillofacial changes on dental implants placed in adults, analyze the clinical implications of these changes, identify prognostic factors, and offer possible solutions.

OVERVIEW

The relationship between implant placement and maxillofacial changes, occurring during not only the active growth period but also the entire span of adulthood, has not been extensively examined. Vertical differences between implants and adjacent teeth due to the ankylotic behavior of the former might be observed at any age and endanger restoration biologically, functionally, and esthetically. Regarding interproximal contacts, firm contact loss may occur within a few months after restoration, resulting in food impaction. Many prognostic factors have been reported, but most do not exhibit a statistically significant association with implant infraocclusion and interproximal contact loss. Incorporation of alternative solutions, accurate treatment planning, strict recall protocols, and retrievability of implant-supported restorations can facilitate efficient management of complications.

CONCLUSION

Maxillomandibular changes throughout adulthood may lead to complications such as implant infraocclusion and interproximal contact loss. Rehabilitation of edentulism should be characterized by well-designed and flexible treatment plans to resolve long-term complications efficiently. Further long-term clinical studies are needed to identify other risk factors.

CLINICAL SIGNIFICANCE

Treatment plans for implant therapy should be reconsidered for adults. Careful patient monitoring and early intervention are essential for securing treatment outcomes.

Proximal contact loss between implant prostheses and adjacent natural teeth: a qualitative systematic review of prevalence, influencing factors and implications

Objectives

To evaluate the prevalence of proximal contact loss (PCL) between implant prostheses and natural teeth, and identify the risk factors and implications associated with PCL.

Data/sources

PubMed (MEDLINE), Google Scholar, Cochrane Library Database, Scopus, EMBASE, Open Grey, ScienceDirect, and Web of Science were electronically searched to retrieve clinical studies on PCL around implant prostheses up to September 2021.

Study selection

A total of 19 studies were eligible. The short-term studies (less than 2 years) revealed a PCL prevalence of 11–30%, the medium-term studies (2–5 years) indicated a PCL prevalence of 13–65%, and the long-term studies (more than 5 years) showed a PCL prevalence of 29–83.3%. The likely influencing factors were the duration of service and the mesial location of proximal contacts. Other factors, such as occlusion, vitality of adjacent teeth, implant location, patient age and splinting had a less obvious relation to PCL. The reported implications of PCL were food impaction and patient dissatisfaction. Bone loss, peri-implant inflammation, bleeding on probing and pocket depth had a less clear association with PCL.

Conclusions

PCL development between implant prostheses and natural teeth is frequent, inevitable and progressive. While the review identified several influencing factors and implications of PCL, future research is needed to outline the influence of prosthesis design on PCL and food impaction.

Clinical significance

Patients with implant prostheses should be informed about PCL likelihood and the risk of food impaction around implant prostheses. The proximal contact quality and its implications should be monitored during the review visits.

Older adults' facial characteristics compared to young adults' in correlation with edentulism: a cross sectional study

Background

Facial ageing is a result of superficial wrinkling combined with changes to the underlying soft tissues and skeleton. The influence of tooth loss, as a geriatric characteristic, on facial appearance is still poorly explained. The aim was to evaluate the facial characteristics of older adults, correlate these characteristics with the dentition and make comparisons with young adults using a non-invasive 3D methodology.

Methods

90 participants older than 65 years, classified into 3 subgroups (edentulous, partially edentulous, toothed) and 30 young adults were evaluated. Their faces were scanned with an optical Artec 3D-scanner. Cephalometric analyses were made using the RapidForm computer program. An independent t-test and ANOVA were used for the comparisons. Pairwise, post-hoc tests were applied with respect to the significant differences (P < 0.05).

Results

The faces of older adults are wider and longer because of the longer middle facial height. Older adults also have a longer upper lip, a larger nose, a smaller nasolabial angle (due to the nasal ptosis), narrower upper- and lower-lip vermilions and larger facial and lower-facial-height angles, resulting in a flat facial profile.

The facial changes due to ageing are the most pronounced in the edentulous. In comparison with the toothed, they have a smaller facial height due to the smaller lower facial height, larger nasolabial angle, smaller mouth width, shorter upper lip and narrower lip vermilions. Their profile is flatter and their lips are more retruded.

Conclusions

The proportions of the whole face are changed in older adults and they are the most expressed when this is combined with tooth loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03190-5.

Rejuvenation of the ageing face and the role of orthodontics: Guidelines for management

The article reviews the ageing changes of the midfacial and maxillary bones, the mandible, the overlaying soft tissues and the smile, and presents clinical guidelines aiming to rejuvenate older faces by means of orthodontic therapy. With regard to the ageing changes, the maxillary skeleton appears to rotate clockwise inferior to the orbit and becomes retrusive, and as a general pattern the midface contracts and deteriorates with age. Resorption below the mental foramen, reduction in alveolar height, loss of bone at the chin region, and relative increase in size and shape are signs of an aged mandible. Epidermal thinning and decrease in collagen in combination with the effect of gravity and various external factors contribute to the ageing of the skin. Atrophy of the superficial and deep fat, changes in ligamentous tissues and changes in muscle structure, position and tone, all contribute to the stigmata of the aged face. In the article, two late adulthood orthodontic cases are discussed as examples, and general guidelines for orthodontic management of the older face aiming at reversing the 'shrinkage' of the tissues by restoring the facial shape and tightening the soft tissue mask are described. The possible mechanisms explaining the changes observed on the faces of the clinical cases are also discussed. A properly planned and executed orthodontic intervention reversing changes from the inside-out before embarking on cosmetic surgery might have a synergistic effect multiplying the benefits for adult patients.

The Facial Aging Process From the "Inside Out"

The normal course of aging alters the harmonious, symmetrical, and balanced facial features found in youth, not only impacting physical attractiveness but also influencing self-esteem and causing miscommunication of affect based on facial miscues. With this evidence-based paper, the authors aim to provide a comprehensive overview of the latest research on the etiology and progression of facial aging by explaining the aging process from the “inside out,” that is, from the bony platform to the skin envelope. A general overview of the changes occurring within each of the main layers of the facial anatomy is presented, including facial skeleton remodeling, fat pad atrophy or repositioning, changes in muscle tone and thickness, and weakening and thinning of the skin. This is followed by an in-depth analysis of specific aging regions by facial thirds (upper, middle, and lower thirds). This review may help aesthetic physicians in the interpretation of the aging process and in prioritizing and rationalizing treatment decisions to establish harmonious facial balance in younger patients or to restore balance lost with age in older patients.

Geometric morphometric analysis of growth patterns among facial types

Introduction:

Extreme patterns of vertical facial divergence are of great importance to clinicians because of their association with dental malocclusion and functional problems of the orofacial complex. Understanding the growth patterns associated with vertical facial divergence is critical for clinicians to provide optimal treatment. This study evaluates and compares growth patterns from childhood to adulthood among 3 classifications of vertical facial divergence using longitudinal, lateral cephalograms from the Craniofacial Growth Consortium Study.

Methods:

Participants (183 females, 188 males) were classified into 1 of 3 facial types on the basis of their adult mandibular plane angle (MPA): hyperdivergent (MPA >39°; n = 40), normodivergent (28° ≤ MPA ≤ 39°; n = 216), and hypodivergent (MPA <28°; n = 115). Each individual had 5 cephalograms between ages 6 and 20 years. A set of 36 cephalometric landmarks were digitized on each cephalogram. Landmark configurations were superimposed to align 5 homologous landmarks of the anterior cranial base and scaled to unit centroid size. Growth trajectories were calculated using multivariate regression for each facial type and sex combination.

Results:

Divergent growth trajectories were identified among facial types, finding more similarities in normodivergent and hypodivergent growth patterns than either share with the hyperdivergent group. Through the use of geometric morphometric methods, new patterns of facial growth related to vertical facial divergence were identified. Hyperdivergent growth exhibits a downward rotation of the maxillomandibular complex relative to the anterior cranial base, in addition to the increased relative growth of the lower anterior face. Conversely, normodivergent and hypodivergent groups exhibit stable positioning of the maxilla relative to the anterior cranial base, with the forward rotation of the mandible. Furthermore, the hyperdivergent maxilla and mandible become relatively shorter and posteriorly positioned with age compared with the other groups.

Conclusions:

This study demonstrates how hyperdivergent growth, particularly restricted growth and positioning of the maxilla, results in a higher potential risk for Class II malocclusion. Future work will investigate growth patterns within each classification of facial divergence.

Estimating Craniofacial Growth Cessation: Comparison of Asymptote- and Rate-Based Methods

OBJECTIVE

To identify differences between asymptote- and rate-based methods for estimating age and size at growth cessation in linear craniofacial measurements.

DESIGN

This is a retrospective, longitudinal study. Five linear measurements were collected from lateral cephalograms as part of the Craniofacial Growth Consortium Study (CGCS). Four estimates of growth cessation, including 2 asymptote- (GC_asym, GC_err) and 2 rate-based (GC_abs, GC_10%) methods, from double logistic models of craniofacial growth were compared.

PARTICIPANTS

Cephalometric data from participants in 6 historic longitudinal growth studies were included in the CGCS. At least 1749 individuals (870 females, 879 males), unaffected by craniofacial anomalies, were included in all analyses. Individuals were represented by a median of 11 images between 2.5 and 31.3 years of age.

RESULTS

GC_asym consistently occurred before GC_err and GC_abs consistently occurred before GC_10% within the rate-based approaches. The ordering of the asymptote-based methods compared to the rate-based methods was not consistent across measurements or between males and females. Across the 5 measurements, age at growth cessation ranged from 13.56 (females, nasion-basion, GC_asym) to 24.39 (males, sella-gonion, GC_err).

CONCLUSIONS

Adolescent growth cessation is an important milestone for treatment planning. Based on our findings, we recommend careful consideration of specific definitions of growth cessation in both clinical and research settings since the most appropriate estimation method may differ according to patients' needs. The different methods presented here provide useful estimates of growth cessation that can be applied to raw data and to a variety of statistical models of craniofacial growth.

Vertical eruption of anterior maxillary teeth adjacent to single-implant-supported crowns: An assessment after a 3-year follow-up period

STATEMENT OF PROBLEM

Vertical eruption of teeth adjacent to an implant has been reported clinically and might affect the esthetic outcome over time. The prevalence of the problem is unclear.

PURPOSE

The purpose of this prospective clinical trial was to evaluate the vertical eruption of anterior maxillary teeth adjacent to single-implant crowns after a 3-year follow-up period.

MATERIAL AND METHODS

Thirty single dental implants were inserted in maxillary anterior sites including the first premolar. The mean age of the participants at implant-supported crown insertion was 48.4 years (range 23 to 79 years). Each implant was restored with a 1-piece screw-retained ceramic single crown. The vertical changes of 60 adjacent anterior maxillary teeth were evaluated from periapical radiographs and casts at baseline, 6, 12, and 36 months.

RESULTS

A global ANOVA test showed statistically significant differences for the outcomes of the distance-implant platform and cement-enamel junction (DPC) (P<.001), crown length distal (P=.021) and mesial (P=.035), implant crown length (P=.022), and incisal edge to edge (P<.001).

CONCLUSIONS

Continuous vertical tooth eruption next to a single dental implant was observed in adult participants.

Evaluation of the distance between the root apices of the upper first molars and the hard palate in an Eastern Mediterranean population: A retrospective study

OBJECTIVE

The aims of this retrospective study were, first to evaluate the distance between the root apices of the upper first molars and the palatal plane (PP), and second to determine the validity (accuracy) of the use of cephalometric radiographs or panoramic X-rays compared to cone beam computed tomography (CBCT) in determining this distance.

MATERIAL AND METHODS

The distance was calculated from the root apices of the first molars to PP, on the cephalometric radiographs of 204 subjects and then 57 measurements were compared to those obtained on panoramic X-rays and CBCT images, in order to find a statistically significant difference according to age, sex, side, vertical and sagittal skeletal patterns, and to determine if 2D radiographs are suitable for this task.

RESULTS

The distance increased significantly in subjects after 20 years of age and in hyperdivergent patients, but was not influenced by sex, side or anteroposterior position of the mandible. No statistical significance was found between the calculated measurements on cephalometric and CBCT radiographs, but both were different from those taken on panoramic X-rays.

CONCLUSIONS

Cephalometric radiographs are reliable in the assessment of the distance between the roots of the upper molars and the PP. In hyperdivergent and adult patients, posterior teeth have enough space between their roots and the upper limit of the hard palate to undergo intrusion mechanics using miniscrews, but care must be taken while planning and managing these movements in order to minimize the unwanted side effects.

Three-Dimensional Photogrammetric Study on Age-Related Facial Characteristics in Korean Females

Background

Understanding the age-related morphological changes of facial soft tissue is fundamental in achieving improved outcomes of rejuvenating procedures. Three-dimensional (3D) photogrammetry is a reliable and convenient anthropometric tool to assess facial soft tissue.

Objective

The aim of this study was to establish age-related facial soft tissue morphology in Korean adult females using non-invasive 3D photogrammetry.

Methods

One hundred and ninety-two female participants were divided into three groups based on age: the younger group (aged 20~39 years), middle group (40~59 years), and older group (60~79 years). Thirty-six landmarks were identified via 3D photogrammetric scanning (Morpheus 3D, Morpheus Co., Ltd., Seongnam, Korea). Forty-one facial dimensions were analyzed using the imaging software to find significance between the age groups.

Results

Smaller upper-facial volume (p=0.019) and shorter upper-facial height (p=0.034) were observed in the older group than in the younger group. In the mid-face, narrowed palpebral fissure (p<0.001) with elongated upper eyelid height (p<0.001) and widened nose (p<0.001) were observed in the older group compared with the younger group. Longer lower-facial height (p<0.001) with longer and wider philtrum (p<0.001, p=0.004, respectively), shorter lower vermilion height (p<0.001), wider mouth width (p<0.001), and smaller lower vermilion angle (p<0.001) were seen in the older group when compared with the younger group. Moreover, greater angles of nasofrontal, nasomental, and labiomental angle (p=0.015, p=0.015, p=0.080, respectively), and smaller nasofacial angle (p=0.034) were observed in the older group than in the younger group.

Conclusion

Our results provide clues of aging-related facial morphological characteristics in Korean female population.

Angular changes in implants placed in the anterior maxillae of adults: a cephalometric pilot study

OBJECTIVES

Completion of adolescent growth represents the earliest time point for implant placement, yet craniofacial growth persists into adulthood and may affect implant position. We aimed to assess whether implants placed in the anterior maxillae of adults show angular changes over time.

MATERIAL AND METHODS

We conducted a cephalometric pilot study in postpubertal patients with no growth disorders, skeletal malformations, or parafunctions. The patients received a single implant in the anterior maxilla and no orthodontic or orthognathic treatment afterwards. We measured angular changes of implants and central incisors on cephalograms taken immediately and after at least 5 years postoperatively with the Sella-Nasion line (SNL) and the nasal line (NL) as references. Changes in implant-SNL angles were the primary outcome.

RESULTS

In 21 patients (30.2 ± 11.5 years at surgery) after a mean follow-up of 8.6 ± 1.3 years, implant-SNL angles and implant-NL angles changed in 81% and 57% of implants, respectively. Implant-SNL changes ranged from 3° counterclockwise to 4° clockwise and were more prevalent in males (100% vs. 58%) and patients under 30 at surgery (85% vs. 63%); mean absolute differences were larger in males (1.8 ± 1.0° vs. 1.3 ± 1.4°) and patients under 30 at surgery (1.5 ± 1.4° vs. 1.1 ± 1.4°). Incisor-SNL angles and incisor-NL angles changed in 89% and 32% of incisors, respectively.

CONCLUSIONS

Implants placed in the anterior maxillae of adults show modest angular changes over time.

CLINICAL RELEVANCE

Changes in implant angles have potential functional and esthetic consequences.

Relationships between skeletal morphology and patterns of bilateral agenesis of third molars in Japanese orthodontic patients

The aim of this study was to reveal the correlations between bilateral agenesis of third molars (M3s) and skeletal morphology in Japanese male and female orthodontic patients. Sixty patients (30 males, 30 females), with bilateral agenesis of maxillary M3s and without agenesis of mandibular M3s (group U), and 60 patients (30 males, 30 females), with bilateral agenesis of mandibular M3s and without agenesis of maxillary M3s (group L), were selected as agenesis groups. Additionally, 60 patients (30 males, 30 females) with all four M3s were selected as the control group (group C). Patients in these three groups had no agenesis of teeth other than M3s. Lateral cephalograms of each patient were used to evaluate skeletal morphology of the maxilla and mandible. Two-way analysis of variance was used for statistical comparisons. Groups U and L had significantly smaller maxillary length and area than group C. Group U exhibited a significantly smaller lower facial height than group C. Males showed significantly larger maxillary length; total mandibular and mandibular body length; mandibular ramus height; SNB angle; maxillary area; and mandibular symphysis, corpus and ramus areas than females. Females had significantly larger lower facial height, gonial angle and ANB angle than males. Smaller maxillary length and area and lower facial height should be considered in planning orthodontic treatment for patients with bilateral agenesis of maxillary and mandibular M3s.

Timing of implant placement after traumatic dental injury

Dental implants are reliable to replace teeth lost because of traumatic dental injury. However, dental implants behave like ankylosed teeth and should not be placed in growing individuals because of the risk of infraposition. This risk may be reduced by ensuring arrested skeletal growth and ideal incisal support. The timing of implant placement may be immediate, early, conventional, or late and is determined by the extent of the trauma, remaining growth, and conditions of the hard and soft tissues. Timing should allow an observation period to properly evaluate the prognosis of concomitantly traumatized neighboring teeth. Orthodontic alignment is often necessary after traumatic dental injury in young individuals to provide symmetric dental conditions around the facial midline, to allow implant placement in the correct 3-dimensional position for the later prosthetic reconstruction, and to ensure sufficient mesiodistal space that leaves a minimum of 1.5 mm of healthy alveolar bone between the future implant and neighboring teeth. Space and stable occlusion should be maintained by bonded retainers and a splint used during the night. A partial prosthesis is usually recommended as a temporary replacement. If a fixed provisional prosthesis is required, it is crucial that it does not interfere with the remaining growth and incisal support and allows proper oral hygiene.

The treatment dilemma of missing maxillary lateral incisors-Part II: Implant restoration

OBJECTIVE

This second of a two-part series reviews the single dental implant as the most current treatment alternative for replacement of a missing or lost maxillary lateral incisor. Assessments of dental maturity for implant placement, implant space requirements, surgical and restorative influence on soft tissue profiles, and implant success are reviewed.

OVERVIEW

Recent data indicates that implant success rates are high, and esthetics and soft tissue profiles appear to be stable for maxillary lateral incisor implants. Implant placement should be assessed by dental maturity of the specific patient as opposed to chronological age, and implant spacing should be developed and assessed by all team members.

CONCLUSIONS

Implant replacement of a missing lateral incisor is a predictable treatment mode if implant placement is deferred until dental maturity and then accurately placed in a well-developed site. Treatment involves more complicated planning and execution from team members than other alternatives, but innovations in techniques and materials render it a favorable alternative for lateral incisor replacement.

CLINICAL SIGNIFICANCE

Implant restoration of a missing or lost maxillary lateral incisor is surgically and restoratively more complex than space closure or a resin-bonded fixed dental prosthesis but demonstrates high success rates and high esthetic potential when team members follow strict treatment protocols.

Interproximal Open Contacts Between Implant Restorations and Adjacent Teeth. Prevalence - Causes - Possible Solutions

PURPOSE

To present the prevalence and contributing factors of interproximal contact loss (ICL) between implant restorations and adjacent teeth, and to provide recommendations for possible prevention and treatment of this complication.

MATERIALS AND METHODS

The authors explored the dental literature on PubMed on ICL between implants and adjacent teeth, interproximal contacts, open contacts, teeth migration causes, facial bone formation, and facial bone changes.

RESULTS

ICL between fixed implant prostheses and adjacent teeth has been reported. A literature search revealed 7 studies showing a high prevalence of ICL between implant prostheses and adjacent teeth. The literature indicates that this ICL is greater in the mesial aspect in comparison with the distal. As identified by the literature review, ICL in the maxilla ranged between 18% and 66% versus 37% to 54% in the mandible. ICL might occur as early as 3 months after prosthetic treatment. The literature review documented possible tooth migration causes, crown-related causes, and bone formation/growth-related causes of ICL.

CONCLUSIONS

ICL is a common multifactorial implant complication. The clinical condition will dictate if the implant crown needs to be modified/replaced or the natural tooth needs to be restored to reestablish interproximal contact between an implant prosthesis and adjacent tooth. Periodic evaluations of interproximal contacts between implant restorations and the adjacent teeth and the use of screw-retained restorations due to ease of removal is recommended to diagnose and mitigate the problem. An orthodontic retainer or occlusal guard may help prevent ICL between the implant restoration and the adjacent tooth.

The rise and fall of the alveolar process: Dependency of teeth and metabolic aspects

The alveolar bone has a unique capacity to follow the teeth's movements. It is formed around erupting teeth and their periodontal ligaments: the more the teeth have erupted, the larger the alveolar process. Throughout life the teeth erupt and migrate in an occlusal and mesial direction to compensate for attrition, an evolutionary trait. After tooth extraction, the alveolar process is resorbed to varying degrees. The mandibular alveolar bone mirrors skeletal bone condition. Due to fast bone turnover (which is the fastest in the whole skeleton), low bone mass and increased fracture risk may first be seen here. If a periapical radiograph of the mandibular premolars shows a dense trabeculation with well-mineralized trabeculae and small intertrabecular spaces, it is a reliable sign of normal skeletal bone density (BMD) and low skeletal fracture risk, whereas a sparse trabecular pattern indicates osteopenia and high fracture risk. The bone turnover rate in the mandible is twice that of the maxilla, and may, hypothetically, play a role in the development of osteonecrosis of the jaw (ONJ), which has been found mainly in the mandibular alveolar process?

Continuous eruption of maxillary teeth and changes in clinical crown length: A 10-year longitudinal study in adult women

BACKGROUND

Continuous physiologic eruption of teeth may become a main aesthetic issue for implants inserted in the maxillary anterior region.

PURPOSE

To study maxillary tooth vertical changes during a 10 years period by 3-dimensional superimposition of digital dental casts.

MATERIAL AND METHODS

Alginate impressions were taken at both baseline and at the 10-year follow-up in a sample of 24 adult Swedish women (average age of 48 years at T0). The upper arch plaster casts were digitized with a 3-dimensional scanner and then superimposed on the palate and the palatal rugae. Occlusal and gingival anatomic structures were digitized for each upper tooth from first molar to first molar. The vertical changes of these structures gave an indication of tooth extrusion and apical or coronal displacement of the gingival margin.

RESULTS

A trend was found for eruption in the anterior region (+0.3 mm on average) while a slight extrusion if not any was found in the first molars and premolars area. Vertical displacement of the gingival margin showed also a positive trend from first molars to incisors. Negative average values, corresponding clinically to gingival recession, were found on first molars (-0.36 mm) and premolars (-0.15 mm), while no displacement was detected in the anteriors. Clinical crown lengths increased in all teeth and it is mainly due to gingival recession for first molars and premolars, while for the incisors the eruption is coupled to a slight equivalent gingival coronal migration.

CONCLUSIONS

During a 10-year period, continuous eruption takes place in female adult subjects, especially in the upper incisors area while gingival recession occurred in first molars and premolars area leading to crown length elongation. Implant placement in the anterior area of the maxilla may have an aesthetic impact even in mature adults due to the continuous eruption of the adjacent teeth.

Acid Erosion: An Increasingly Relevant Dental Problem. Risk Factors, Management and Restoration

A review of risk factors and management of acid erosion. Particular emphasis is placed on the use of direct composite as a reversible and relatively straightforward restorative option.

Estimating effects of craniofacial morphology on gingival recession and clinical attachment loss

OBJECTIVES

Evidence on possible associations between facial morphology, attachment loss and gingival recession is lacking. We analysed whether the facial type, which can be described by the ratio of facial width and length (facial index), is related to periodontal loss of attachment, hypothesizing that a broad face might be associated with less gingival recession (GR) and less clinical attachment loss (CAL) than a long face.

MATERIALS AND METHODS

Data from the 11-year follow-up of the population-based Study of Health in Pomerania were used. Periodontal loss of attachment was assessed by GR and CAL. Linear regression models, adjusted for age and gender, were used to assess associations between specific landmark based distances extracted from magnetic resonance imaging head scans and clinically assessed GR or CAL (N = 556).

RESULTS

Analysing all teeth, a higher maximum cranial width was associated with a lower mean GR (B = -0.016, 95% CI: -0.030; -0.003, p = 0.02) and a lower mean CAL (B = -0.023, 95% CI: -0.040; -0.005, p = 0.01). Moreover, a long narrow face was significantly associated with increased mean GR and CAL (facial index, P for trend = 0.02 and p = 0.01, respectively). Observed associations were more pronounced for incisors and canines than for premolars and molars.

CONCLUSION

This study revealed craniofacial morphology, specifically the cranial width and the facial index, as a putative risk factor for periodontal loss of attachment.

Three-dimensional analyses of aging-induced alterations in facial shape: a longitudinal study of 171 Japanese males

We sought to generate data to facilitate forensic facial comparisons. Specifically, we conducted a longitudinal study of alterations in face shape induced by aging. We obtained two three-dimensional facial shape measurements in 171 Japanese males at intervals of approximately 10 years. With this data, we created a homologous model consisting of 10,741 data points for each face based on 33 anatomical landmarks. We averaged the movements of corresponding data points between the two homologous models for each individual and used this data to predict up to 30 years of face aging in an average Japanese male. We clearly identified aging-induced shape changes, such as drooping and denting of the facial folds, drooping of the upper lip, and projection of the lower eyelid, in the virtually aged model. A quantitative comparison of aging-induced shape alterations among three age groups (individuals in their 20's, 30's, and 40-50's) showed that these alterations accelerated more quickly as age increased. Using our predictive model, we conducted a preliminary study focused on facial shape alterations induced by reductions in body weight. Our findings indicated that our proposed method would also be valid for this purpose.

Tooth wear and dentoalveolar remodeling are key factors of morphological variation in the Dmanisi mandibles

The Plio-Pleistocene hominin sample from Dmanisi (Georgia), dated to 1.77 million years ago, is unique in offering detailed insights into patterns of morphological variation within a paleodeme of early Homo. Cranial and dentoalveolar morphologies exhibit a high degree of diversity, but the causes of variation are still relatively unexplored. Here we show that wear-related dentoalveolar remodeling is one of the principal mechanisms causing mandibular shape variation in fossil Homo and in modern human hunter-gatherer populations. We identify a consistent pattern of mandibular morphological alteration, suggesting that dental wear and compensatory remodeling mechanisms remained fairly constant throughout the evolution of the genus Homo. With increasing occlusal and interproximal tooth wear, the teeth continue to erupt, the posterior dentition tends to drift in a mesial direction, and the front teeth become more upright. The resulting changes in dentognathic size and shape are substantial and need to be taken into account in comparative taxonomic analyses of isolated hominin mandibles. Our data further show that excessive tooth wear eventually leads to a breakdown of the normal remodeling mechanisms, resulting in dentognathic pathologies, tooth loss, and loss of masticatory function. Complete breakdown of dentognathic homeostasis, however, is unlikely to have limited the life span of early Homo because this effect was likely mediated by the preparation of soft foods.

Effect of age on single implant submersion rate in the central maxillary incisor region: a long-term retrospective study

BACKGROUND

It is contraindicated to place dental implants before growth and development are completed as they are at a risk of submersion due to growth arrest, creating a potential aesthetic problem.

PURPOSE

The present study evaluated the effect of age on mean submersion rate of single dental implant in the central maxillary incisor area as compared with the adjacent natural tooth in implants placed after growth has ceased.

MATERIALS AND METHODS

A retrospective study was conducted on 35 patients (mean age 29.3 ± 9.9 years, 21 females) who received a single dental implant replacing a missing maxillary central incisor from 1992 to 2008 with a follow-up of at least 3 years. Clinical photos from last follow-up were digitally analyzed to measure the vertical change between the incisal edge of the implant supported crown and the adjacent natural central incisor.

RESULTS

In the younger age group (≤30 years), the submersion rate was more than three times higher than in the older age group (>30 years), yielding submersion rates of 1.02 and 0.27% per year, respectively.

CONCLUSIONS

Whereas implant submersion continues throughout adult life, its rate varies with age. It is evident that this phenomenon is much more conspicuous during the second and third decades of life as compared with the fourth and fifth.

Postnatal changes in the growth dynamics of the human face revealed from bone modelling patterns

Human skull morphology results from complex processes that involve the coordinated growth and interaction of its skeletal components to keep a functional and structural balance. Previous histological works have studied the growth of different craniofacial regions and their relationship to functional spaces in humans up to 14 years old. Nevertheless, how the growth dynamics of the facial skeleton and the mandible are related and how this relationship changes through the late ontogeny remain poorly understood. To approach these two questions, we have compared the bone modelling activities of the craniofacial skeleton from a sample of subadult and adult humans. In this study, we have established for the first time the bone modelling pattern of the face and the mandible from adult humans. Our analyses reveal a patchy distribution of the bone modelling fields (overemphasized by the presence of surface islands with no histological information) reflecting the complex growth dynamics associated to the individual morphology. Subadult and adult specimens show important differences in the bone modelling patterns of the anterior region of the facial skeleton and the posterior region of the mandible. These differences indicate developmental changes in the growth directions of the whole craniofacial complex, from a predominantly downward growth in subadults that turns to a forward growth observed in the adult craniofacial skeleton. We hypothesize that these ontogenetic changes would respond to the physiological and physical requirements to enlarge the oral and nasal cavities once maturation of the brain and the closure of the cranial sutures have taken place during craniofacial development.

Long-term therapeutic efficacy of oral appliances in treatment of obstructive sleep apnea-hypopnea syndrome

Objective:

To investigate the long-term efficacy and safety of oral appliances (OAs) in treating obstructive sleep apnea-hypopnea syndrome (OSAHS) by length of treatment.

Materials and Methods:

This is a retrospective study to review the usage of OAs in Chinese OSAHS patients in recent decades. Ninety-four valid questionnaires were returned by 412 patients with OSAHS receiving OA treatment. Among the wearers, 22 agreed to follow-up polysomnography, and 25 agreed to follow-up cephalograms. Tolerance and side effects of OAs were assessed by a survey. Comparisons of efficacy were carried out between the initial and follow-up polysomnography measurements. Cephalometric analysis was used to investigate skeletal and occlusal changes to determine safety of the OAs.

Results:

The longest treatment extended to 147 months, with a median of 74 months (first and third quartiles, 30 and 99 months, respectively). Among the participants, 14.9% had been treated for more than 120 months. Side effects were temporary and relatively minimal and included tooth soreness (37.2%), dry mouth (33.0%), odd bite feeling (31.9%), and excess salivation (30.8%). Polysomnography proved that OAs remained effective for the treatment of OSAHS in the long term; initial Apnea-Hypopnea Index values were reduced from a median of 24.50 (quartiles, 14.65, 54.05) without the OA to 7.40 with the OA (2.12, 10.00), and follow-up median values were 25.55 without the OA (11.71, 43.65) and 4.25 with the OA (1.38, 7.70). Cephalometric analysis indicated mild and slow changes in the skeleton and occlusion after average treatment duration of 5 years.

Conclusion:

OAs provided effective and safe long-term therapy for patients with OSAHS. Follow-up supervision is recommended since long-term alterations take place, although these appear to be minimal.

Long-term function of single-implant restorations: a 17- to 19-year follow-up study on implant infraposition related to the shape of the face and patients' satisfaction

BACKGROUND

Various levels of infraposition of single-implant restorations have been observed in long-term follow-up studies, but little knowledge is available on the biological mechanism behind this pattern.

PURPOSE

The primary aim of this study is to report the frequency and severeness of implant infraposition in the anterior single-implant application after 17 to 19 years in function and, secondly, to try to relate these observations to anatomical appearance of the shape of the face of the patient.

MATERIALS AND METHODS

The present study comprised of 57 patients who were provided with 65 CeraOne™ single-tooth restorations (Nobel Biocare AB, Gothenburg, Sweden) between 1989 and 1991. Altogether 46 of these patients were treated with single implants in the anterior region. Besides clinical and radiographic data, clinical photographs, study casts, and patient's assessment of the long-term aesthetic result (visual analog scale) was collected at the termination of the present study. The degree of implant crown infraposition was related to assessed facial shape and to patient and clinical assessment of the aesthetic result by means of Pearson's correlation test. To increase the numbers of patients, another group of 25 patients presented in another similar study were pooled with the present material for prevalence calculations.

RESULTS

Altogether 47 patients showed up for the final examination after an average of 18 years (82%). Two implants failed (18 years cumulative survival rates [CSR]- 96.8%) and eight original single-crown restorations were replaced (CSR 83.8%). Three of the replaced crowns were replaced because of infraposition of the crowns. About 40% of the patients showed signs of infraposition, similar in younger and older age groups, but more frequently observed in female patients at termination of the study (p < 0.05). There was a weak trend indicating an association between "long-face" appearance and infraposition of the crown restoration (p > 0.05), and patients were more satisfied with the aesthetic clinical result than the participating clinicians (p < 0.05).

CONCLUSION

Single-implant restorations in the anterior upper jaw may present small degrees of infraposition in long-term perspectives. Female patients seem to be at a higher risk of infraposition (p < 0.05), but no clear relationship between age at implant placement or facial shape and degree of infraposition was possible to establish (p > 0.05). Patients were more satisfied with the aesthetic result, as compared with the clinicians (p < 0.05), and patients seemed to pay less attention to the degree of infraposition in their aesthetic assessments, as compared with most of the clinicians.

Gingival changes and secondary tooth eruption in adolescents and adults: a longitudinal retrospective study

INTRODUCTION

Our aim was to investigate 8 years of vertical changes of the gingival margin and tooth displacement of maxillary molars and incisors in adolescents and adults.

METHODS

Twenty-five adolescents and 10 adults were included in this study, with dental casts taken 2 and 10 years after orthodontic treatment. The gingival contour of the teeth was traced digitally using calibrated photographs of the 2 dental casts, and gingival changes were measured on crown superimposition. Eruption of the central incisors and first molar were measured on dental casts after scanning and superimposition on the palatal vault.

RESULTS

Adults and adolescents presented a mean molar eruption of 0.27 and 0.34 mm and a mean incisor eruption of 0.39 and 0.73 mm, respectively. Adults and adolescents presented a mean molar gingival displacement of respectively 0.34 and 0.77 mm, and the adolescents a mean incisor gingival displacement of 0.44 mm. Correlation between secondary tooth eruption and gingival displacement was obtained only for the incisors in the adolescent group.

CONCLUSIONS

Adolescents and adults presented apical displacement of the gingival contour of the maxillary first molars, as was the case for maxillary incisors in adolescents. Secondary eruption of maxillary first molars and central incisors continues in adolescents and adults.

Regional shape change in adult facial bone curvature with age

Life expectancies have increased dramatically over the last 100 years, affording greater opportunities to study the impact of age on adult craniofacial morphology. This article employs a novel application of established geometric morphometric methods to examine shape differences in adult regional facial bone curvature with age. Three-dimensional semilandmarks representing the curvature of the orbits, zygomatic arches, nasal aperture, and maxillary alveolar process were collected from a cross-sectional cranial sample of mixed sex and ancestry (male and female; African- and European-American), partitioned into three age groups (young adult = 18-39; middle-aged = 40-59 years; and elderly = 60+ years). Each facial region's semilandmarks were aligned into a common coordinate system via generalized Procrustes superimposition. Regional variation in shape was then explored via a battery of multivariate statistical techniques. Age-related shape differences were detected in the orbits, zygomatic arches, and maxillary alveolar process. Interactions between age, sex, and ancestry were also identified. Vector plots revealed patterns of superoinferior compression, lateral expansion, and posterior recession depending on the population/subpopulation, location, and age groups examined. These findings indicate that adult craniofacial curvature shape is not static throughout human life. Instead, age-related spatial modifications occur in various regions of the craniofacial skeleton. Moreover, these regional alterations vary not only through time, but across human populations and the sexes.

Soft tissue morphology of Jordanian adolescents

OBJECTIVE

To determine soft tissue cephalometric norms of a sample of Jordanian adolescents and to compare them with those of North Americans.

MATERIALS AND METHODS

Forty-one subjects aged 14 to 17 years were selected from a larger random and representative sample of 320 adolescents attending 12 schools in the capital of Jordan, Amman. Seven reference lines were identified and traced according to definitions by Holdaway and Ricketts, and 2 angular and 12 linear measurements were analyzed.

RESULTS

Significant differences were found between males and females in measurements of soft tissue facial angle, H angle, subnasale to H line, basic upper lip thickness, upper lip thickness and labrale inferius and superius to E line (P < .05). Males had a more prominent upper lip in relation to the overall soft tissue profile, while the lips of females were considerably more retrusive in relation to the nose and chin. Jordanian norms were similar to those of North Americans, with only two exceptions: the H angle and skeletal convexity which were 5.4 degrees and 3.2 mm greater in Jordanians, respectively.

CONCLUSIONS

Jordanian soft tissue norms were similar to American norms with the exception of the former having a more prominent upper lip position in relation to the overall soft tissue profile.