When managing patients with missing teeth in the esthetic zone, several critical factors influence treatment planning and modality selection, including growth status, nature of malocclusion, gingival display and architecture, chronological age, and adjacent teeth. Available treatment options include orthodontic space closure, resin-bonded bridges, autotransplantation, temporary miniscrew–retained pontics, and implant placement—some of which may be affected by continued dentoalveolar development. This article identifies patient growth as a special consideration, examines the key determinants guiding treatment selection, and presents evidence-based recommendations for management of missing anterior teeth, with a special emphasis on the anterior maxilla.
Highlights
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Edentulous spaces in the esthetic zone can be managed through various treatment modalities, each with inherent distinct risks and benefits.
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Appropriate patient selection and informed decision-making are essential for determining the optimal treatment approach.
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Implant-supported restorations are widely used for tooth replacement, though potential complications necessitate the consideration of alternative treatment.
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Continued craniofacial and dentoalveolar growth, regardless of chronological age, may result in hard and soft tissue complications with implants.
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Treatment recommendations are inherently multifactorial, integrating biological and patient-specific factors.
Successful management of missing anterior teeth requires careful patient selection and thorough patient education, integrating patient-specific variables (age, growth potential, hard- and soft-tissue characteristics, and gingival display) with extrinsic factors (finances, patient preferences, and practitioner expertise). Etiologies, such as congenital agenesis, unrestorable decay, periodontal loss, or trauma, are encountered across all ages, with esthetic and psychosocial impact being heightened with involvement of the anterior maxilla. As such, clinicians should strive to achieve the most optimal and lasting esthetic outcome. Canine substitution, or orthodontic space closure, is an evidence-based approach used to eliminate the need for prolonged treatment. However, Maryland bridges, autotransplantation, and implant-borne restorations are options that may also be considered. ,,, Although osseointegrated implants present a popular restorative option for replacing teeth without compromising the adjacent dentition, this fixture cannot fully replicate the biomechanical properties of a natural tooth; therefore, residual risks must be acknowledged.
Irrespective of the treatment selection, the decision made by the provider and patient must take into consideration the effects of a patient’s growth and development to ensure stable results.
This article identifies considerations for treatment selection, assesses potential complications, and provides evidence-based guidelines for the management of missing anterior teeth, with a special focus on the esthetic zone from an orthodontic perspective.
Determinants of Treatment selection
From the patient’s perspective, media exposure, finances, and personal preferences may guide their selection, with the clinician’s input further influencing their treatment decision. A perusal of publications suggests that, in most cases, laypeople preferred space closure over implants, and that surveyed dentists and orthodontists found outcomes from either implants or space closure equally pleasing. Robertsson and Mohlin reported that patients treated with space closure showed higher satisfaction than those treated with a fixed prosthetic bridge, but the single implant as a replacement option was not included in this study. Beyond this predilection, neither temporomandibular joint nor periodontal compromises were observed in the long term.
The clinician’s specialty is likely to strongly influence their treatment recommendation: restorative practitioners may favor prosthetics, including implantology, maxillofacial surgeons and periodontists may lean toward implant-based approaches, and orthodontists may prefer space closure depending on the presentation. Regardless of the discipline, the most favorable option is based on a multitude of factors, with a particular concern for growth status in the case of implant treatment. Key contributors include space considerations, status and morphology of neighboring teeth, nature of the malocclusion, tooth and soft tissue exposure in the smile, age, long-term stability and esthetics, and the architecture of the gingivae. ,
Craniofacial growth
Consideration of the patient’s growth potential and pattern is a required element in orthodontic treatment planning, and it should be incorporated into all deliberations on the treatment choice for missing teeth, given its effects on occlusion. A landmark publication outlining craniofacial growth was published by Björk in 1968, initiating a body of orthodontic literature that further expanded on the fundamentals of growth and maturation in relation to the dentition. , Essentially, the maxilla grows via posterosuperior remodeling accompanied by anteroinferior displacement, occurring simultaneously with the eruption of the dentition. The vertical dimension of occlusion is determined by the balance of the vertical growth of the middle cranial fossa and the mandibular rami, with an equivalent vertical development of the nasomaxillary complex and dentoalveolar components of the jaws. In the transverse dimension, the maxilla develops anteriorly and even more greatly posteriorly. The enlargement of the maxilla and mandible is complemented by the vertical and horizontal drift of the dentition, which may have a substantial effect on the occlusion. Most of this phenomenon occurs before skeletal maturity, but it does not stop in adulthood; instead, it continues at a slower rate, as research disproves the common misconception that growth ceases entirely. ,,,,,,,,,,,,,,
In adolescents with missing maxillary incisors, treatment should account for their remaining skeletal and craniofacial growth. In fact, adults should be evaluated similarly, as alveolar bone adaptation may compromise the results of their treatment. If an implant-supported restoration is to replace a missing anterior tooth, analogously to an ankylosed tooth, its lack of a periodontal ligament will prevent the implant from erupting and moving like the adjacent natural teeth. The vertical and horizontal drift of the adjacent teeth and alveolus, compared with the ankylosed implant, results in the risk of submersion of the implant position in the maxilla, referred to as implant infraposition (IIP) ( Fig 1 ). The submerged position of the implant may disrupt occlusal relationships and cause extrusion of the opposing dentition, tipping of adjacent teeth, loss of proximal contacts, and gingival discrepancies between the implant and the adjacent teeth. Furthermore, these effects may cascade into periodontal and restorative complications.
A, The implant crown is restored to match the occlusion of the adjacent dentition ( line a ); B, After dentoalveolar or craniofacial changes, the implant remains at the original occlusion ( line a), demonstrating IIP, leading to gingival margin disharmony and occlusal discrepancy ( line b ).
Determining growth potential
Traditionally, hand-wrist radiographs, serial cephalometric radiographs, and cervical vertebral maturation have been used to assess growth potential. Although these methods tend to show a final stage of development, they fail to indicate the completion of dentoalveolar development. A study by Pancherz et al found large amounts of sagittal and vertical skeletofacial growth in patients beyond 20 years of age, long after radial epiphyseal closure, corroborating its ineffectiveness as an indicator for completed growth. It is challenging not only to determine growth potential, but also to identify predisposing predictors or risk factors for infraposition ( Table I ). ,,,,,,,,,,,,,, No definitive criteria or diagnostic methods currently exist to identify the completion of such dentoalveolar changes, which may impact the determination of the ideal time for a patient’s implant placement.
Table I
Etiologic factors associated with IIP ,,
| Etiologic factors | |
|---|---|
| Localized | Malocclusion |
| Implant placement, design, and location | |
| Hard and soft tissue characteristics | |
| Iatrogenic factors | |
| Idiopathic factors | |
| Systemic | Periodontal disease |
| Osteoporosis | |
| Genetic | Gender |
| Facial type | |
| Craniofacial and dentoalveolar growth and development |
Implant infraposition
Beyond the esthetic discrepancies, open proximal contacts and missing interproximal papillae are also among the possible consequences of IIP ( Table II ). A systematic review and meta-analysis revealed that approximately half the patients with implants exhibited infraposition, as well as 46.3% of implants demonstrated proximal contact loss. Cocchetto et al conducted a follow-up of 76 implants after an average of 10.7 years and found that 73.3% of patients displayed IIP. Despite studies analyzing the occurrence of IIP and gender, long and/or short facial types, implant location, or other hypothesized factors, there appears to be no reliable consensus to predict future infraposition. ,,,,,,,,,,,,,,
Table II
Patient and implant findings related to IIP
| Study | Participants | Age, y (mean ± SD) | Follow-up, y (mean ± SD) | Implant site | Findings |
|---|---|---|---|---|---|
| Bernard et al |
YA: 14 (5 M and 9 F)
MA: 14 (5 M and 9 F) Total: 28 (10 M and 18 F) |
YA: 15.5-21.0 (18.4)
MA: 40.0-55.0 (43.6) Total: 15.5-50.0 (NR) |
1.8-9.1 (4.2) | Single maxillary anterior | IIP occurrence and extent in mature adults were similar to young adults, despite differences in growth potential |
| Vilhjálmsson et al | Total: 26 (15 M and 11 F) | Total: 20.0-56.0 (34.8) | 3.0 | Single maxillary anterior | IIP occurrence was observed in all adult patients because of continued growth and marginal bone changes |
| Schwartz-Arad and Bichacho |
YA: 22 (7 M and 15 F)
MA: 13 (6 M and 7 F) Total: 35 (21 M and 15 F) |
YA: NR-29.0 (22.7 ± 4.3)
MA: 30.0-NR (40.4 ± 5.6) Total: NR (29.2 ± 10.9) |
(7.5 ± 4.5) | Single maxillary central incisor | IIP occurrence was observed throughout adult life, with a mean submersion rate higher in in second and third decades than in the fourth and fifth decades |
| Cocchetto et al |
YA: 26 (12 M and 14 F)
MA: 34 (14 M and 20 F) Total: 60 (26 M and 34 F) |
YA: 20.0-29.0 (NR)
MA: 29.0-65.0 (NR) Total: 20.0-65.0 (34.8 ± 10.1) |
5.0-20.0 (10.7 ± 4.0) | Maxillary anterior | IIP occurrence was observed in 73.3% of adult patients, with 61.4% of patients being aware of IIP |
| Andersson et al | Total: 34 (20 M and 14 F) | Total: 18.0-56.0 (31.4 ± 10.8) | 17.0-19.0 (18.5 ± 0.9) | Maxillary anterior |
IIP occurrence was observed in patients with single-implant restorations in the anterior maxilla after 15-20 y of follow-up
A higher risk of greater IIP was observed in females |
| Jemt et al | Total: 25 (18 M and 7 F) | Total: NR (26.9 ± 11.1) | 15.0-17.0 (15.9 ± 0.7) | Maxillary anterior | A higher risk of IIP was observed in females, possibly because of increased anterior facial height (N-Gn) and posterior rotation of the mandible |
| Brahem et al | Total: 57 (20 M and 37 F) | Total: 18.0-61.0 (29.7 ± 10.0) | ≥5 (7.0 ± 1.0) | Maxillary anterior | Most patients showed a natural tooth displacement in both vertical and horizontal planes after a minimum 5-y period |
| Bergenblock et al | Total: 57 (32 M and 25 F) | Total: 15.0-57.0 (31.9 ± 10.7) | 17.0-19.0 (18.4 ± 0.9) | Maxilla and mandible | IIP was the most common indication for crown replacement for patients studied |
| Gjelvold et al | Total: 87 (36 M and 51 F) | Total: 17.0-68.0 (NR) | 3.6-11.1 (7.5 ± 1.6) | Maxilla and mandible | A higher risk of IIP was observed in females, >1 mm |
| Thilander et al | Total: 10 (NR) | Total: 14.0-19.0 (15.4) | 0.0-8.0 | Maxillary anterior | Neither chronological age nor dental stage should guide implant placement because of the continuous eruption of teeth postadolescence |
SD, standard deviation; YA , young adults; MA , mature adults; M , males; F , females; NR , not reported.
This concern encompasses all ages, despite the assumption that adults meet the criteria for implant restorations because they have completed growth. IIP has been reported in both adolescent and adult patients across several studies, ,,, eliminating age as a requisite for implants ( Fig 2 ). Bernard et al observed infraposition in a sample of patients aged 40-55 years at the time of implant placement, when growth was thought to be complete. These findings in patients past chronological and skeletal maturation prompt the question of how to determine an appropriate time for implant placement. ,,,,,,,,,,,,,,
A, Intraoral view of IIP in a 65-year-old man at 20 years postplacement. Presenting IIP is likely because of multifactorial causes, as the implant was placed in his late 40s with no significant periodontal history. The soft tissue margin of the implant crown ( a ) is 2 mm apical to the soft tissue margin of the natural incisor ( b ); B, Panoramic radiograph of a 65-year-old man at the initial visit to evaluate the compromised esthetics of the infraoccluded restoration. Courtesy of Professor Jae-Seung Chang, Department of Prosthodontics, Gangnam Severance Dental Hospital, Yonsei University College of Dentistry, Seoul, South Korea .
Periodontal complications
Correction of IIP is often complex, requiring advanced surgical procedures that may not always guarantee a favorable outcome ( Table III ). ,,,,,, Clinical follow-up of implant-supported restorations has documented gingival inflammation, implant visibility through the mucosa, gingival recession, compromised interproximal papillae, and soft tissue discoloration, in addition to the submerged implant ( Fig 3 ). ,, Remedies may be surgical or orthodontic. A study found orthodontic tooth extrusion to effectively regenerate the proximal bone and papilla adjacent to a single maxillary implant in a less invasive manner than surgery. The heightened risk of peri-implantitis and inflammation is attributable to an increased transmucosal depth of the implant-abutment interface, which diminishes accessibility for plaque control and promotes a shift in the microbial flora. This dysbiosis exacerbates bone resorption, augments the likelihood of peri-implantitis, and could jeopardize implant survival.
Table III
Solutions for soft and hard tissue findings in IIP ,,,,,,,,
| Findings | Solutions |
|---|---|
| Occlusal discrepancy between the implant and the natural adjacent teeth | Evaluate status of the implant and consider orthodontic treatment if necessary. |
| Remove the implant and replace the edentulous area with a fixed prosthesis | |
| OBS to reposition the implant | |
| Segmental osteotomy to reposition the implant | |
| Remove and replace with a new implant | |
| Labial plate resorption | Preventive bone graft to fill the space between the implant and the labial plate |
| Soft tissue (interdental papillae, free gingival margin, and attached gingiva) alteration | OBS to modify the gingival alignment |
| Orthodontic tooth movement | |
| Preventive placement of connective tissue graft | |
| Proper patient selection based on the gingival phenotype | |
| Marginal bone loss around adjacent teeth | Careful evaluation of the periodontium and implant |
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