| Abstract|| |
Spacing in dentition negatively interferes with harmony of the smile. A lot of literature has been devoted to prosthetic closure of such space(s) in the dentition; however, the only option for maintaining space(s) in tooth-supported fixed dental prosthesis (FDP) is with the aid of loop connectors. Eleven patients (seven males and four females) with mean age of 45.18 years (range 22-70 years), previously treated with porcelain fused to metal full coverage restorations joined with loop connectors, were evaluated clinically to assess the clinical status and longevity of treatment provided. All the patients were asked to fill a simple close-ended questionnaire to provide their perspective on the limitations and outcome of the treatment and rate their satisfaction level on the scale of 1-10. The cumulative survival of the FDPs with the aid of loop connectors was 90.9%. There was no reported esthetic failure and, at the time of responding to the questionnaire, none of the patients had active complaint with respect to the prosthesis and all but one of the patients were satisfied with the treatment provided. Clinical survivability and the patient feedback suggests that customized designing of loop connectors for each patient is an excellent treatment modality to successfully maintain excessive (single/generalized) spacing between teeth and effectively splint pathologically migrated and mobile teeth. The reported problems with this treatment option are all transient in nature.
Keywords: Diastema, fixed dental prosthesis, loop connectors, splinting
|How to cite this article:|
Bhandari S, Bakshi S. Survival and complications of unconventional fixed dental prosthesis for maintaining diastema and splint pathologically migrated teeth: A case series up to 8 years follow-up. Indian J Dent Res 2013;24:375-80
Spacing between teeth or diastema is a common esthetic problem and it negatively interferes with harmony of the smile. It is frequent to encounter a clinical situation with excessive pontic space or presence of localized/generalized spacing between the teeth in need of prosthetic restorations. When pre-prosthetic orthodontic space correction (closure/reduction) is ruled out, then depending upon the span of spacing and patient wishes, diastema can be maintained or closed in the restoration. However, the final esthetic outcome and effect on the attachment apparatus should be considered before it is decided to close the diastema with the prosthesis.
|How to cite this URL:|
Bhandari S, Bakshi S. Survival and complications of unconventional fixed dental prosthesis for maintaining diastema and splint pathologically migrated teeth: A case series up to 8 years follow-up. Indian J Dent Res [serial online] 2013 [cited 2020 Feb 26];24:375-80. Available from: http://www.ijdr.in/text.asp?2013/24/3/375/118018
Etiology of diastema varies from a normal finding in children to pathological conditions like supernumerary teeth, mesiodens, cysts, fibromas, and pathological migration due to periodontal disease. Adult tooth size discrepancies (dentoalveolar discrepancy) and excessive vertical overlap of incisor are the most common factors in midline diastema.  Diastema greater than 2 mm and diastema in patients with generalized spacing are at risk of not closing with normal development. 
Bolton analysis and cast discrepancy analysis can be utilized to determine quantitative space discrepancies and can accurately convey the feasibility of space closure with prosthetic restorations.  Closing diastema with conventional fixed dental prosthesis (FDP) without considering golden proportion would fail to create an esthetically pleasing appearance and has detrimental effects on the periodontium. , In such cases, it is prudent to maintain the space(s) in the prosthesis. The only treatment option available for maintaining the space(s) in an FDP is with the aid of loop connectors.
- Patient wishes to maintain the diastema.
- Presence of excessive pontic space.
- Multiple, joined prosthetic restorations in clinical situations with presence of localized or generalized spacing between abutments.
- Prosthetic restorations for pathologically migrated and periodontally weak teeth (Grade I and II).
- Clinical situation requiring "jumping off" the immediate adjacent abutment. This may be done when the prognosis of primary abutment in uncertain and patient desires to retain it.
- Food lodgment and hygiene maintenance below the loop connectors, especially in patients with limited manual dexterity.
- Interference in tongue movements and speech.
- Relative flexibility as compared to conventional connectors.
After teeth preparation, an area is marked (with the indelible pencil) on the slope of the palate where the maximum curve of the loop will be placed. The mark is placed with clinical judgment to be as close as possible to the tooth and least visible. An irreversible hydrocolloid impression is made to transfer the mark on the cast, which is then related to the master cast. Sprue wax (Wax wires, Bego, Bremen, Germany) is used to create loop(s) and is attached at the cervical margin of the wax pattern. Conventional casting and ceramic layering procedures are followed to complete the prosthesis.
Designing of loop connectors
The ideal requirement is to have an inconspicious connector with maximum rigidity. Length of edentulous span, location in the mouth, esthetics, opposing occlusion, and gender of the patient dictate alteration in length, circumferential form, and diameter of the loop to meet the demands for each patient. Clinical situations with multiple missing teeth, pathologically migrated and mobile teeth, and teeth in the posterior quadrant of male patients require loops with maximum rigidity [Figure 1]. In such cases, combination of decreased length, round/half round form of cross section, and increased diameter can be used to increase the rigidity of the connector. Flexible connectors are not desired; however, smaller length, round form, with smaller diameter loops can be utilized in patients with hypersensitive palate.
|Figure 1: Loops designed for maximum rigidity: Decreased length, increased diameter, and round form of cross section|
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Distribution of space amongst the individual units of fixed partial denture was done on the cast, keeping esthetics and occlusion into consideration. Diagnostic wax up was shown to all the patients to help them in making the decision. To further educate the indecisive patients, a set of temporaries with closed spaces and subsequently another set of temporaries with maintained spaces were shown.
The longest case is followed up for a period of 8 years and recent patient for 2 years. Cases were grouped according to the usage of loop connectors.
Group 1: Loop connectors for maintaining diastema in clinical situations with excessive space between the abutments.
Group 2: Loop connectors for splinting pathologically migrated teeth.
Group 3: A case of its use when bypassing (jumping off) the primary abutment was necessary in planning for FDP.
A 26-year-old male patient in good general health reported with missing maxillary incisors, lost due to trauma 8 months previously. He desired to have FDP as his marriage was nearing. Intraoral examination and diagnostic cast evaluation revealed the presence of excessive pontic space and it was not possible to compensate for the excessive space in the prosthesis. Patient was educated about the maintenance of diastema with loop connectors between each unit of the prosthesis. He reported of having diastema in natural teeth, therefore he did not have any objection in maintaining them also. In this particular patient, loop connectors were designed for maximum rigidity [Figure 2]. Usage of Superfloss (Oral B, London, UK) was demonstrated as the oral hygiene aid, in addition to routine oral hygiene measures. Oral hygiene measures were reinforced and evaluated at subsequent follow-ups. He has been without any complaints for 8 years now and gave the feedback on mail and telephone.
|Figure 2: Metal framework with loop connectors designed for maximum rigidity|
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Rehabilitation for five more patients was completed following the same guidelines, and they are regularly followed up and are without any complaints.
Such patients have periodontally weak and migrated abutments. Prosthetic restoration with conventional FDP becomes very difficult to plan because of misaligned abutments and excessive space formation between them. Loop connectors in such cases are designed for maximum rigidity to maintain spaces between the teeth and splint them together. Four such cases were completed and are regularly followed up.
Patient 1: A 60-year-old male presented with the chief complaint of an unesthetic and functionally deficient FDP done 6 years back [Figure 3]. He was very comfortable with the generalized spacing in the teeth and desired for spacing between individual prosthetic units. The abutments were periodontally compromised with loss of supporting bone, therefore it was decided to use loop connectors to maintain space and splint the individual units together. Four-unit porcelain fused to metal prosthesis on the left side and three-unit porcelain fused to metal FDP on the right side were cemented in place, maintaining spaces between individual abutments and midline diastema. Patient regularly comes for dental check up and 4 years follow-up revealed no discomfort at all in function and oral hygiene maintenance [Figure 4].
|Figure 3: Functionally deficient prosthesis with generalized spacing in maxillary dentition|
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|Figure 4: Palatal view showing the well-maintained and healthy gingival tissue at 4 years follow-up|
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Patient 2: A 42-year-old male patient was treated for unusually long and unaesthetic, grade 2 mobile left maxillary central incisor [Figure 5]. Single full coverage prosthetic restoration for this tooth was not conducive for a long-term good prognosis and it was not possible to close the diastema between the central incisors. After its required periodontal and endodontic treatment, it was decided to splint left maxillary central incisor with right maxillary central incisor with the aid of loop connector. Since the right maxillary central incisor was periodontally stable, round form of sprue wax with greater gauge was used to provide rigidity in the connector. Three years follow-up showed healthy and stable attachment apparatus [Figure 6].
|Figure 5: Preoperative view with a long unesthetic and pathologically migrated left central incisor|
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Group 3: Bypassing or "jumping off" the primary abutment
A 68-year-old male reported for the restoration of missing right mandibular incisors. Intraoral clinical and radiographic examination showed periodontally stable right canine, left lateral incisor, and left canine. The left mandibular central incisor showed loss of alveolar bone till the apical third on the mesial side, but the tooth was clinically firm [Figure 7]. Patient was given the option of extracting left mandibular central incisor and implant-supported prosthesis in the edentulous region, which he refused. He was not willing for the extraction even after explaining the uncertain prognosis of using the left central incisor as a prospective abutment. In such a scenario, he was then given the option of "jumping" this weak tooth using a loop connector, to which he readily agreed. A five-unit FDP was cemented with right canine, left lateral incisor, and left canine as abutments. Loop connector was used to connect right central incisor pontic with left lateral incisor.
|Figure 7: Intraoral periapical view showing extent of alveolar bone loss in left mandibular primary abutment|
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At 1 year and 6 months post cementation, prosthesis was stable; however, calculus deposit was noted along the loop near the pontic, as the patient reportedly stopped using any form of cleansing aid [Figure 8]. Oral prophylaxis was done, and use of Superfloss and following routine oral hygiene instructions were reinforced [Figure 9]. At 3 years follow-up, the gingival health around the loop was stable.
|Figure 9: Usage of superfloss for effective removal of plaque around and below the loop connector|
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| Materials and Methods|| |
Eleven patients (seven males and four females) with a mean age of 45.18 years (age range of 22-70 years), who received tooth-supported fixed partial dentures with the aid of loop connectors in last 8 years, were clinically evaluated. In addition, they were asked to fill a simple close-ended questionnaire (appended below) to identify the difficulties they experienced and their present perspective on the functional and esthetic outcome of the treatment provided. Same format was given to all the patients of each group. One patient from Group 1 gave feedback through mail and was considered functioning well with the prosthesis. The level of satisfaction was rated on a scale of 1-10.
Longevity was assessed based on the clinical examination of the prosthesis, response of the tissues around the loop connectors, and clinical mobility of the abutments.  Superfloss was passed below the loops to evaluate any perceptible discomfort and/or bleeding. Rehabilitation was considered a failure if any complication reported by the patient and/or found during clinical evaluation led to a new prosthesis fabrication. However, the treatment was considered a success if the reported and/or observed complication could be treated in the mouth.
| Results|| |
In one patient, the FDP was remade due to the fracture of the loop connector. None of the patients (all three groups included) had any active complaint with the prosthesis [Table 1]. Nine patients (five in Group 1 and four in Group 2) presented with pre-existing diastema/generalized spacing and were receptive to the maintenance of spaces in the FPD.
|Table 1: Data based on the filled questionnaire forms by patients of all three groups (yes is given score 1, no is given score 0)|
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| Discussion|| |
The only viable option available to maintain spaces in FPDs is with the aid of loop connectors, which is both esthetically and mechanically challenging. Earlier, the use of loop connectors was limited to maintain diastema between central incisors and for replacing a single pontic only.  This case series aptly depicts the multiple utilities of loop connectors in not only managing excessive (single/multiple) pontic space(s), but also to splint pathologically migrated teeth effectively. Individually designed connectors by varying the circumferential form, diameter, and length of the loops provide variability to the treatment plan to meet the requirements of each clinical situation.
Clinically, only one FDP was categorized as failure due to the fracture of loop connector. New prosthesis was made after increasing the diameter of the loop while keeping the length and circumferential form the same. Two female patients who had experienced multiple problems after prosthesis delivery desired to have a new prosthesis with closed spaces. Both did not cite any specific reason for their desire; therefore, new prosthesis was not made for them.
These connectors are reportedly over contoured, and are therefore difficult to clean off the plaque.  There was no evidence of food accumulation or gingival inflammation around the loop connectors and no discomfort was reported at the time of clinical evaluation. Only one patient (Group 3) showed calculus deposit along the loop at 1½ years follow-up and he admitted to have not used any kind of oral hygiene measures below the loop connector after 1 year of prosthesis delivery. Due emphasis has to be given to the oral hygiene maintenance around the loops by proper usage of Superfloss in plaque removal below the loop connectors. Good manual dexterity and motivation, however, are the limiting factors.
Interference in tongue movements and discomfort in speech has been a minor problem and was cited longest for one patient who adapted to it over a period of 3 weeks. This problem was anticipated in this patient as she was hypersensitive to all the prosthetic procedures.
Conventional FDP connectors are understandably more rigid as compared to loop connectors. This flexibility of loop connectors can relatively be overcome by using shorter lengths and increasing the diameter of the loop, and if possible, still keeping their form as round as possible.  None of the patients perceived mobility during function and no objective mobility of significance was observed in the FDP units. Mobility of pathologically migrated abutments decreased from Grade II to Grade I.
| Conclusion|| |
Despite the less number of patients, the clinical survivability and data seem to suggest that individually designed loop connectors meet all the requisite parameters of space maintenance, esthetics, function, and splinting pathologically migrated and mobile teeth successfully in FDP. The reported difficulties are transient in nature and can be effectively taken care of by patient education, reinforcing hygiene instructions, and regular follow-up.
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Unit of Prosthodontics, Oral Health Sciences Centre, PGIMER, Chandigarh
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]